RU2637446C2 - Methods for processing titanium alloys - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: method for grinding a billet grain size containing titanium alloy includes beta annealing of the billet, cooling to a temperature below the beta transition temperature of the titanium alloy, and comprehensive forging of the billet. Comprehensive forging involves forging on the press in the direction of the first orthogonal axis of the billet at a deformation rate sufficient for adiabatical heating of the billet inner area, forging the billet on the press in the direction of the second orthogonal axis of the billet with a deformation rate sufficient for adiabatical heating of the billet inner area, forging the billey on the press in the direction of the third orthogonal axis of the billet with a deformation rate sufficient for adiabatic heating of the billet inner area, and repeating at least one forging on the press to achieve total true deformation of at least 1.0. The temperature for forging the billet is in the temperature range from 100°F (55.6°C) below titanium alloy beta transition temperature to a temperature of 700°F (388.9°C) below titanium alloy beta transition temperature, and the deformation rate used during forging on the press is in the range of 0.2^s-1up to 0.8^s-1.

EFFECT: produce fine-grained alloy structure at higher deformation rates.

40 cl, 16 dwg, 1 tbl, 6 ex

Description

STATEMENT OF GOVERNMENT-SPONSORED RESEARCH OR DEVELOPMENT

[0001] The present invention was carried out with the support of the United States Government under contract NIST No. 70NANB7H7038, concluded with the National Institute of Standards and Technology (NIST) of the United States Department of Commerce. The US government may have certain rights in the present invention.

FIELD OF TECHNOLOGY

[0002] The present invention relates to methods for processing titanium alloys.

BACKGROUND

[0003] Methods of manufacturing titanium and its alloys having coarse-grained (CG), fine-grained (FG), very fine-grained (VFG) or ultrafine-grained (UFG) microstructure encompass the use of multiple reheating and forging steps. The forging steps may include one or more sludge forging steps in addition to hood forging on an open die press.

[0004] The following terms are used in relation to the microstructure of titanium alloys in the present application: the term "coarse grain", referring to alpha grain sizes in the range from 400 microns and less to more than about 14 microns; the term "fine grain", referring to the size of alpha grains in the range from 14 microns and less to more than 10 microns; the term "very fine grain", referring to alpha grain sizes in the range from 10 μm and less to more than 4.0 μm; and the term “ultrafine grain”, referring to alpha grain sizes of 4.0 μm or less.

[0005] In known commercial processes for forging titanium and titanium alloys, deformation rates of 0.03 s ^-1 to 0.10 s ^-1 using multiple reheating and forging steps are used to form coarse or fine grain microstructures.

[0006] In the known methods for the manufacture of fine-grained, very fine-grained or ultrafine-grained microstructures, a comprehensive forging (MAF) process is used with an ultra-slow deformation rate of 0.001 s ^-1 or slower (as described, for example, in the Materials Science Forum ("Forum of Scientific Materials ") (Salischev G. et al.), Edition 584-586, pp. 783-788 (2008)). A comprehensive comprehensive forging process is described, for example, in C. Desrayaud, et al., Journal of Materials Processing Technology, 172, pp. 152-156 (2006).

[0007] The key to grain grinding during comprehensive forging with an ultra-slow strain rate is the ability to operate continuously in dynamic recrystallization mode, which is the result of the ultra-slow used strain rates, i.e. 0.001 s ^-1 or slower. During dynamic recrystallization, the simultaneous formation of a kernel of grains occurs, their growth and the accumulation of dislocations. The generation of dislocations in freshly formed grain continuously reduces the driving force for grain growth, and the nucleation of grain is energetically favorable. In the forging process with ultra slow deformation rate, dynamic recrystallization is used to continuously recrystallize grains during forging.

[0008] Relatively uniform cubes of the Ti-6-4 ultrafine alloy (UNS R56400) can be made using the all-round forging method with ultra-slow deformation rate, but the total time taken to complete the all-round forging steps may be too long for commercial applications. In addition, the characteristics of the known large-sized commercially available open-die forging and pressing equipment may not provide the ability to use the ultra-slow deformation rates required in such embodiments, and thus, it may be necessary to comprehensively forge commercial batches of products using an ultra-slow deformation rate specialized forging equipment.

[0009] Thus, an object of the present invention preferably is to provide a method for manufacturing titanium alloys having a coarse-grained, fine-grained, very fine-grained or ultrafine-grained microstructure that does not require multiple reheating and which allows the use of increased strain rates, reduces the time required for processing , and / or eliminates the need for specialized forging equipment.

SUMMARY OF THE INVENTION

[0010] According to a non-limiting aspect of the present invention (disclosure), a method for grinding grain size of a preform containing a titanium alloy comprises beta annealing the preform. After beta annealing, the preform is cooled to a temperature below the beta transition temperature of the titanium alloy. Then the workpiece is subjected to comprehensive forging. Comprehensive forging includes the steps according to which: forging a workpiece on a press at a forging temperature of a workpiece located in the temperature range of the forging of the workpiece in the direction of the first orthogonal axis of the workpiece with a deformation rate sufficient to adiabatically heat the inner region of the workpiece, forging the workpiece on the press at a temperature forging a workpiece in the temperature range of forging a workpiece in the direction of the second orthogonal axis of the workpiece with a strain rate sufficient for batch heating the inner region of the preform, and forging the preform on the press at a temperature of the forging preform, which is in the temperature range of the forging preform, in the direction of the third orthogonal axis of the preform with a strain rate sufficient to adiabatically heat the inner region of the preform. Optionally, between successive forging steps on a press, it is possible to cool the adiabatically heated inner region of the workpiece to a workpiece forging temperature or close to it in the workpiece forging temperature range and heat the workpiece outer surface to a workpiece forging or close to it in the workpiece forging temperature range. At least one of the forging steps on the press is repeated until a total deformation of at least 1.0 is achieved in the workpiece. According to another non-limiting embodiment, at least one of the forging steps on the press is repeated until a total deformation in the range of at least 1.0 to less than 3.5 is achieved in at least one area of the workpiece. According to one non-limiting embodiment, the strain rate used during forging on the press is in the range of 0.2 s ⁻¹ to 0.8 s ⁻¹ .

[0011] According to another non-limiting aspect of the present invention, a non-limiting embodiment of a method for grinding grain size of a preform containing a titanium alloy includes a beta annealing step of the preform. After beta annealing, the preform is cooled to a temperature below the beta transition temperature of the titanium alloy. Then the workpiece is subjected to comprehensive forging using a sequence that includes the following forging steps.

[0012] The workpiece is forged on the press at a workpiece forging temperature in the range of workpiece forging temperatures, in the direction of the first orthogonal axis A of the workpiece for blocked upsetting to the main upset height with a strain rate sufficient to adiabatically heat the inner region of the workpiece. Used in this application, the main deposited height after upsetting is the distance equal to the desired final size after forging, for each orthogonal axis of the workpiece.

[0013] The workpiece is forged on a press at a workpiece forging temperature in the range of workpiece forging temperatures in the direction of the second orthogonal axis B of the workpiece for blocked upsetting to the first deposited height. The first blocked sludge is used to return the preform substantially to the preform forging before forging. Although the strain rate at the first blocked sludge may be sufficient for adiabatic heating of the inner region of the workpiece, according to one non-limiting embodiment, adiabatic heating during the first blocked sludge may not be observed, since the total deformation created during the first blocked sludge may be insufficient for significant adiabatic heating of the workpiece. The first upsetting height of the blocked upsetting is greater than the main upsetting height of the upsetting.

[0014] The workpiece is forged on the press at a workpiece forging temperature in the range of workpiece forging temperatures in the direction of the third orthogonal axis C of the workpiece for blocked upsetting to a second upset height. A second blocked draft is used to return the preform substantially to the preform forging before forging. Although the strain rate during the second blocked draft can be sufficient for adiabatic heating of the inner region of the workpiece, according to one non-limiting embodiment, adiabatic heating during the second blocked draft can not be observed, since the total strain created by the second blocked draft can be insufficient for significant adiabatic heating of the workpiece. The second deposited height of the blocked draft is greater than the main deposited height of the draft.

[0015] The workpiece is forged on the press at a workpiece forging temperature in the range of workpiece forging temperatures, in the direction of the second orthogonal axis B of the workpiece for blocked upsetting to the main upset height with a strain rate sufficient to adiabatically heat the inner region of the workpiece.

[0016] The workpiece is forged on the press at a workpiece forging temperature in the workpiece forging temperature range in the direction of the third orthogonal axis C of the workpiece for blocked upsetting to the first upset height. The first blocked sludge is used to return the preform substantially to the preform forging before forging. Although the strain rate at the first blocked sludge may be sufficient for adiabatic heating of the inner region of the workpiece, according to one non-limiting embodiment, adiabatic heating during the first blocked sludge may not be observed, since the total deformation created during the first blocked sludge may be insufficient for significant adiabatic heating of the workpiece. The first upsetting height of the blocked upsetting is greater than the main upsetting height of the upsetting.

[0017] The workpiece is forged on a press at a workpiece forging temperature in the workpiece forging temperature range in the direction of the first orthogonal axis A of the workpiece for the second blocked draft to the second upset height. A second blocked draft is used to return the preform substantially to the preform forging before forging. Although the strain rate during the second blocked draft can be sufficient for adiabatic heating of the inner region of the workpiece, according to one non-limiting embodiment, adiabatic heating during the second blocked draft can not be observed, since the total strain created by the second blocked draft can be insufficient for significant adiabatic heating of the workpiece. The second deposited height of the blocked draft is greater than the main deposited height of the draft.

[0018] The workpiece is forged on a press at a workpiece forging temperature in the range of workpiece forging temperatures, in the direction of the third orthogonal axis C of the workpiece for blocked upsetting to the main upset height with a strain rate sufficient to adiabatically heat the inner region of the workpiece.

[0019] The workpiece is forged on a press at a workpiece forging temperature in the workpiece forging temperature range in the direction of the first orthogonal axis A of the workpiece for the first blocked draft to the first upset height. The first blocked sludge is used to return the preform substantially to the preform forging before forging. Although the strain rate at the first blocked sludge may be sufficient for adiabatic heating of the inner region of the workpiece, according to one non-limiting embodiment, adiabatic heating during the first blocked sludge may not be observed, since the total deformation created during the first blocked sludge may be insufficient for significant adiabatic heating of the workpiece. The first upsetting height of the blocked upsetting is greater than the main upsetting height of the upsetting.

[0020] The workpiece is forged on a press at a workpiece forging temperature in the range of workpiece forging temperatures in the direction of the second orthogonal axis B of the workpiece for the second blocked draft to the second upset height. A second blocked draft is used to return the preform substantially to the preform forging before forging. Although the strain rate during the second blocked draft can be sufficient for adiabatic heating of the inner region of the workpiece, according to one non-limiting embodiment, adiabatic heating during the second blocked draft can not be observed, since the total strain created by the second blocked draft can be insufficient for significant adiabatic heating of the workpiece. The second deposited height of the blocked draft is greater than the main deposited height of the draft.

[0021] Optionally, between successive steps of forging on a press according to the preceding embodiment of the method, the adiabatically heated inner region of the preform is cooled to approximately the temperature of the forging of the preform in the temperature range of the forging of the preform, and the outer surface of the preform is heated to approximately the temperature of the forging of the preform in the range of forging of the preform. At least one of the forging steps on the press is repeated according to one embodiment until a total deformation of at least 1.0 is achieved in at least one area of the workpiece. According to one non-limiting embodiment, at least one of the forging steps on the press is repeated until a total deformation in the range of at least 1.0 to less than 3.5 is achieved in at least one area of the workpiece. According to one non-limiting embodiment, the strain rate used during forging on the press is in the range of 0.2 s ⁻¹ to 0.8 s ⁻¹ .

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Features and advantages of the device and methods described in this application can be better understood with reference to the accompanying drawings, in which:

[0023] FIG. 1 shows a graph of the theoretical calculation of the volume fractional concentration of the equilibrium alpha phase present in the alloys Ti-6-4, Ti-6-2-4-6 and Ti-6-2-4-2, depending on the temperature;

[0024] FIG. 2 is a flowchart listing the steps of one non-limiting embodiment of a method for processing titanium alloys according to the present invention;

[0025] FIG. 3 schematically illustrates aspects of a non-limiting embodiment of a comprehensive forging process with a high deformation rate using temperature control to process titanium alloys to grind grain sizes, and in FIG. 2 (a), 2 (c) and 2 (e) show non-limiting embodiments of the forging steps in the press, and in FIG. 2 (b), 2 (d) and 2 (f) illustrate optional non-limiting cooling and heating steps according to non-limiting aspects of the present invention;

[0026] FIG. 4 schematically illustrates aspects of a known all-round forging method with a slow deformation rate used to grind grain size in small-scale samples;

[0027] FIG. 5 is a flowchart listing the steps of a method according to one non-limiting embodiment of the processing of titanium alloys according to the present invention, comprising upsetting to a major upset height along orthogonal axes to achieve the final desired workpiece size, and first and second blocked precipitations;

[0028] In FIG. 6 shows a temperature-time graph of thermomechanical processing for a non-limiting embodiment of the high-deformation all-round forging method according to the present invention;

[0029] FIG. 7 shows a temperature-time graph of thermomechanical processing for a non-limiting embodiment of a multi-temperature method of comprehensive forging with a high deformation rate according to the present invention;

[0030] FIG. 8 shows a temperature-time graph of thermomechanical processing for a non-limiting embodiment of the all-round forging method with a high deformation rate with a beta transition crossing according to the present invention;

[0031] FIG. 9 schematically illustrates aspects of a non-limiting embodiment of a multiple precipitation and drawing method for grinding grain size according to the present invention;

[0032] FIG. 10 is a flowchart listing steps of a non-limiting embodiment of a method of processing by repeatedly precipitating and drawing titanium alloys to grind grain size according to the present invention;

[0033] FIG. 11 (a) shows a micrograph of a microstructure of a Ti-6-2-4-2 alloy forged and processed in a known manner;

[0034] FIG. 11 (b) shows a micrograph of a microstructure of a Ti-6-2-4-2 alloy treated by a thermally controlled all-round forging with a high deformation rate according to the embodiment described in Example 1 of the present invention;

[0035] FIG. 12 (a) shows a micrograph of a microstructure of a Ti-6-2-4-6 alloy forged and processed in a known manner;

[0036] FIG. 12 (b) shows a micrograph of a microstructure of a Ti-6-2-4-6-6 alloy treated with a thermally controlled all-round forging with a high deformation rate according to the embodiment described in Example 2 of the present invention;

[0037] FIG. 13 is a micrograph of a microstructure of a Ti-6-2-4-6 alloy treated by thermally controlled all-round forging with a high deformation rate according to the embodiment described in Example 3 of the present invention;

[0038] FIG. 14 is a micrograph of a microstructure of a Ti-6-2-4-2 alloy treated by a thermally controlled all-round forging with a high deformation rate according to the embodiment described in Example 4 of the present invention, as a result of which the same deformation is applied along each axis;

[0039] FIG. 15 is a micrograph of a microstructure of a Ti-6-2-4-2 alloy processed by a thermally controlled all-round forging with a high deformation rate according to the embodiment described in Example 5 of the present invention, according to which, to minimize buckling of the preform that occurs after each main precipitation, blocked sediment;

[0040] FIG. 16 (a) is a micrograph of a microstructure of a central region of a Ti-6-2-4-2 alloy treated by a thermally controlled all-round forging with a high deformation rate according to one embodiment using the beta transition intersection described in Example 6 of the present invention; and

[0041] FIG. 16 (b) shows a micrograph of the microstructure of the surface region of a Ti-6-2-4-2 alloy treated by a thermally controlled all-round forging with a high deformation rate according to one embodiment using the beta junction, which is described in Example 6 of the present invention.

[0042] The above, as well as other details, will become clearer after reading the following detailed description of some non-limiting embodiments of the present invention.

DETAILED DESCRIPTION OF SOME UNLIMITED IMPLEMENTATION OPTIONS

[0043] In the present description of non-limiting embodiments, in contrast to working examples or situations in which it is indicated otherwise, all numbers expressing quantities or characteristics should be understood to be altered in all cases by the term “about”. Accordingly, unless otherwise indicated, any numerical parameters formulated in the following description are approximations that can be changed depending on the desired properties that must be obtained using the methods of the present invention. At least, but not as an attempt to limit the application of the doctrine of equivalents to the scope of protection defined in the paragraphs of the attached formula, each numerical parameter should be considered at least in light of the number of significant digits given and using conventional rounding methods.

[0044] In addition, any numerical range given in this application is intended to contain all sub-ranges assigned to its category. For example, the range "1-10" is intended to contain all subranges between (and including) the specified minimum value of 1 and the specified maximum value of 10, i.e. having a minimum value that is equal to or greater than 1 and a maximum value that is equal to or less than 10. Any maximum numerical limitation indicated in this application contains all lower numerical limitations included in its category and any minimum numerical limitation the restriction indicated in this application contains ever higher numerical limitations included in its category. Accordingly, Applicants reserve the right to amend the present invention, including the paragraphs of the attached claims, to explicitly indicate any subband included in the category of ranges explicitly indicated in this application. All such ranges are intended to be inherently disclosed in this application in such a way that the correction to explicitly designate any such sub-ranges meets the requirements of Law 35 of the United States Code, § 112, Section One, and Law 35 of the United States Code, § 132 (a).

[0045] The grammatical terms "one" and "some", if used in the present description, are intended to be construed in an inclusive sense: "at least one" or "one or more", unless otherwise indicated. Thus, these terms are used in this specification to mean at least one, not only one (ie, “at least one”) of the grammatical objects of the term. For example, the term “component” refers to one or more elements, and thus more than one element, can be considered and can be used or implemented in the implementation of the described implementation options.

[0046] The present invention provides descriptions of various embodiments. It should be understood that all of the embodiments described herein are illustrative and non-limiting. Thus, the invention is not limited to the description of various illustrative and non-limiting examples and embodiments. Rather, the invention is defined solely by the points of the attached claims, which can be corrected to clarify any features explicitly or immanently described or otherwise explicitly or immanently presented in the present invention.

[0047] Any patent, publication, or other published material identified in this application is hereby incorporated by reference in its entirety, unless otherwise indicated, but only to the extent that said included material does not contradict existing definitions, statements or other disclosure materials expressly stated in this application. Also, to the extent necessary, the positive disclosure formulated in this application replaces any conflicting material incorporated by reference into this application. Any material or part thereof that is listed as being incorporated by reference in this application, but which is in conflict with existing definitions, statements or other disclosure materials formulated in this application, is included in this application to the extent that there is no conflict between this material included and existing disclosure material.

[0048] One aspect of the present invention is directed to non-limiting embodiments of a comprehensive forging of titanium alloys, which involves the use of high strain rates during forging steps to reduce grain size. These embodiments of the method are generally indicated in the present invention as "comprehensive forging with a high deformation rate" or "MAF with a high deformation rate." Used in this application, the terms "draft" and "impact", interchangeably refer to the individual stage of forging on the press, in which the workpiece is forged between the surfaces of the stamp. Used in this application, the phrase "deposited height" refers to the size or thickness of the workpiece, measured along one orthogonal axis after precipitation along this axis. For example, after upsetting by forging on the press along a specific axis to a deposited height of 4.0 inches (101.6 mm), the thickness of the workpiece after forging on the press, measured along this axis, is approximately 4.0 inches (101.6 mm ) The concept and use of upsetting heights are known to those skilled in the art of forging in the press and will not be discussed in detail in this application.

[0049] It has been determined above that for the preparation of ultra fine grain workpieces from alloys such as Ti-6Al-4V alloy (ASTM Grade 5; UNS R56400), which may also be referred to as "Ti-6-4" alloy comprehensive forging with a high deformation rate, at which the workpiece is forged at least up to a total deformation of 3.5, should be used. This process is described in US Patent Application No. 12 / 882,538, filed September 15, 2010, under the name "Technological Schemes for Titanium and Titanium Alloys" (hereinafter "Application '538"), which is hereby incorporated by reference in its entirety. Achieving a deformation of at least 3.5 may require a significant processing time and is associated with increased complexity, which increases the cost of production and increases the likelihood of unforeseen problems. The present invention provides a comprehensive forging process with a high deformation rate, which can provide ultra fine grain structures using a total deformation in the range of at least 1.0 to less than 3.5.

[0050] The methods of the present invention include the use of comprehensive forging and its modifications, such as the multiple precipitation and drawing process (MUD) described in the '538 Application, to titanium alloys exhibiting slower efficient alpha phase evolution and growth kinetics than the alloy Ti-6-4. In particular, the alloy Ti-6Al-2Sn-4Zr-2Mo-0.08Si (UNS R54620), which may also be referred to as the alloy "Ti-6-2-4-4", has a slower effective alpha kinetics than Ti-6-4 alloy, as a result of the presence of additional element-stopping grain elements (stopping dislocation migration at the grain boundaries of elements), such as Si. In addition, the alloy Ti-6Al-2Sn-4Zr-6Mo (UNS R56260), which can also be referred to as the alloy "Ti-6-2-4-4", has a slower effective alpha kinetics than the alloy T-6 -4, resulting in increased beta-stabilizing content. It is believed that with respect to the alloy components, the indicated growth and release of the alpha phase are a function of the diffusion rate of the alloy component in the titanium-based alloy. Molybdenum is known to have one of the slowest diffusion rates of all titanium alloys. In addition, beta stabilizers, such as molybdenum, reduce the temperature (T _β ) of the beta transition of the alloy, and lowering the temperature T _β generally leads to a decrease in the diffusion of atoms in the alloy at the processing temperature of this alloy. The result of the relatively slow effective alpha release and growth kinetics for Ti-6-2-4-2 and Ti-6-2-4-6 alloys is that beta heat treatment is used before comprehensive forging according to embodiments of the present of the invention, leads to the formation of a small and stable size of alpha packets in comparison with the effect of such treatment of the alloy Ti-6-4. In addition, after beta-heat treatment and cooling, Ti-6-2-4-2 and Ti-6-2-4-6 alloys have a fine-grained beta structure, which limits the kinetics of alpha grain growth.

[0051] The effective alpha growth kinetics can be estimated by identifying the most slowly diffusing particles at a temperature immediately below the beta transition. This approach is theoretically justified and experimentally verified in the literature (see Semyatin et al., Studies in Metallurgy and Materials A: Metallurgy and Materials , 38 (4), 2007, pp. 910-921). For titanium and its alloys, data on the diffusion ability of all potential alloy components are not always available; However, literature reviews, such as in the "Titan" (second edition, 2007) (Lutjering and Williams), generally agree with the following concerning the classification of some of the common components of the alloy:

D _Mo <D _Nb <D _Al ~ D _V ~ D _Sn ~ D _Zr ~ D _Hf <D _Cr ~ D _Ni ~ D _Cr ~ D _Co ~ D _Mn ~ D _Fe .

[0052] Thus, alloys, such as Ti-6-2-4-6 alloy and Ti-6-2-4-2 alloy, which contain molybdenum, show the desired slow alpha kinetics necessary to achieve ultrafine grain microstructures at relatively low deformation than for Ti-6-4 alloy, in which aluminum diffusion controls kinetics. Based on the relations of the groups of the periodic table, it can also be reasonably argued that tantalum and tungsten belong to the group of slow diffusants.

[0053] In addition to incorporating slowly diffusing elements to reduce the effective kinetics of the alpha phase, decreasing the beta transition temperature in alloys controlled by aluminum diffusion produces the same effect. Lowering the beta transition temperature to 100 ° C reduces the diffusion ability of aluminum in the beta phase by approximately an order of magnitude at the beta transition temperature. Alpha kinetics in alloys such as ATI 425 ^® alloy (Ti-4Al-2,5V; UNS 54250) and Ti-6-6-2 alloy (Ti-6Al-6V-2SN; UNS 56620) are obviously controlled by diffusion aluminum; however, the lower beta transition temperatures of these alloys relative to the Ti-6Al-4V alloy also lead to the desired delayed effective alpha kinetics. The Ti-6Al-7Nb alloy (UNS R56700), typically a biomedical version of the Ti-6Al-4V alloy, can also exhibit delayed effective alpha kinetics due to its niobium content.

[0054] It was initially expected that alpha-beta alloys, with the exception of Ti-6-4 alloy, could be processed under conditions similar to those described in the '538 application at temperatures that would result in similar volumetric fractional concentrations of the alpha phase. For example, according to preliminary estimates made using the PANDAT program, which is an affordable computing tool commercially available from Computherm, LLC, Madison, Wisconsin, USA, it was predicted that Ti-6-4 alloy at a temperature of 1500 ° F (815.6 ° C) should have approximately the same volume fraction of the alpha phase as Ti-6-2-4-2 at 1600 ° F (871.1 ° C) or Ti-6 -2-4-6 at a temperature of 1200 ° F (648.9 ° C), as shown in FIG. 1. However, the Ti-6-2-4-2 and Ti-6-2-4-6 alloys crack during processing in the manner in which the Ti-6-4 alloy in the '538 Application was processed using the temperature for which formation was predicted similar volume fractional concentration of the alpha phase. Successful processing of Ti-6-2-4-2 and Ti-6-2-4-6 alloys requires much higher temperatures, providing reduced equilibrium volume fractions of the alpha phase and / or significantly reduced strain in one pass.

[0055] Each of the changes in the comprehensive forging process with a high deformation rate, including temperature or alpha / beta forging temperatures, deformation rate, impact deformation, pause time between impacts, the number and duration of reheatings and intermediate heat treatments can affect the resulting microstructure, as well as the presence and degree of cracking. Initially, lower total strains were undertaken to block cracking without the hope of achieving ultra-fine granular structures. However, after research, samples processed using reduced total deformations showed a clear prospect of creating ultrafine granular structures. This result was completely unexpected.

[0056] According to some non-limiting embodiments of the present invention, a method for producing ultra-small grain size comprises the steps of: 1) selecting a titanium alloy containing effective alpha-phase growth kinetics that is slower than that of Ti-6-4, 2) beta annealing the titanium alloy to create a stable small alpha packet, and 3) perform comprehensive forging with a high deformation rate (or a similar derivative process, such as the multiple precipitation and drawing process (MUD) described in Application '53 8) for a total strain of at least 1.0, or according to another embodiment for a total strain of at least 1.0 to less than 3.5. The term "small", used in this application to describe grain and packet size, refers to the smallest grain and packet size that can be achieved and which, according to non-limiting embodiments, is on the order of 1 μm. The word "stable" is used in this application to mean that the comprehensive forging steps do not significantly enlarge the size of the alpha grain and do not increase the size of the alpha grain by more than about 100%.

[0057] FIG. Figures 2 and 3 show a flow diagram and a schematic representation of aspects of a non-limiting embodiment of a method (16) using the comprehensive forging with high strain rate (MAF) according to the present invention to reduce grain size in titanium alloys. Before the comprehensive forging step (26), beta-annealing step (18) and a step (20) of cooling the titanium alloy billet 24 are performed. Air cooling can be used with small workpiece sizes, such as, for example, cubic workpieces with a 4-inch (101.6 mm) rib; however, water or liquid cooling may also be used. Faster cooling rates result in a thinner package and reduced alpha grain sizes. Beta annealing (18) includes the steps according to which the preform 24 is heated to a temperature that is higher than the beta transition temperature of the titanium alloy in the preform 24, and this temperature is maintained for some time sufficient to form the entire beta phase in the preform 24. Beta annealing (18) is a process known to one skilled in the art, and thus will not be described in detail in this application. According to one non-limiting embodiment, the beta annealing may include the steps of heating the preform 24 to a beta annealing temperature that is about 50 ° F (27.8 ° C) higher than the beta transition temperature for the titanium alloy, and holding the preform 24 at this temperature for about 1 hour.

[0058] After the beta annealing step (18), the preform 24 in step (20) is cooled to a temperature below the beta transition temperature for the titanium alloy in the preform 24. According to one non-limiting embodiment of the present invention, the preform is cooled to ambient temperature. As used herein, the term "ambient temperature" refers to ambient temperature. For example, according to a non-limiting commercial manufacturing method, the term "ambient temperature" refers to the temperature of the production environment. According to one non-limiting embodiment, cooling (20) may include a hardening step. Quenching involves the steps of immersing the preform 24 in water, oil, or another suitable liquid, and is a process known to one skilled in the art of metallurgy. According to other non-limiting embodiments, in particular for workpieces having a small size, cooling (20) may include air cooling. Any method of cooling a titanium alloy billet 24 that is currently known to the person skilled in the art or which will be known subsequently falls within the protection scope of the present invention. In addition, according to some non-limiting embodiments, cooling (20) includes the step of cooling directly to the forging temperature of the workpiece, which is in the temperature range suitable for forging the workpiece, for subsequent comprehensive forging with a high deformation rate.

[0059] After cooling (20), the workpiece in step (26) is subjected to comprehensive forging with a high deformation rate. Those skilled in the art will appreciate that all-round forging ("MAF"), which may also be referred to as "A-B-C" forging, is a form of severe plastic deformation. Comprehensive forging with a high deformation rate in step (26) according to one non-limiting embodiment of the present invention includes the steps of heating (in step 22, in FIG. 2) a workpiece 24 containing a titanium alloy to a workpiece forging temperature in the workpiece forging temperature range which is within the alpha + beta phase region of the titanium alloy, after which, in step (26), comprehensive forging is performed using a high deformation rate. Obviously, according to one embodiment, in which the cooling step (20) includes cooling to a temperature in the forging temperature range of the workpiece, the heating step (22) is not necessary.

[0060] A high deformation rate is used for all-round forging to adiabatically heat the inner region of the workpiece. However, according to non-limiting embodiments of the present invention, at least in the last ABC forging cycle with a high deformation rate per cycle, the temperature of the inner region of the titanium alloy preform 24 should not exceed the temperature (T _β ) of the beta transition of the titanium alloy in the preform. Thus, according to such non-limiting embodiments, the forging temperature of the workpiece, at least for the final forging cycle ABC or at least for the last impact of the all-round forging cycle with a high deformation rate, should be selected so that during all-round forging with a high deformation rate the area of the workpiece was not equal to or did not exceed the beta transition temperature of the alloy. For example, according to one non-limiting embodiment of the present invention, the temperature of the inner region of the preform does not exceed a temperature that is 20 ° F (11.1 ° C) lower than the beta transition temperature of the alloy, i.e. the temperature T _β is equal to 20 ° F (11.1 ° C) during at least the final ABC impact cycle with a high deformation rate during the comprehensive forging process or during at least the last forging press stroke in which the total deformation is at least in the area of the workpiece is at least 1.0 or is in the range from at least 1.0 to less than 3.5.

[0061] In a non-limiting embodiment of the comprehensive forging with a high deformation rate according to the present invention, the temperature of the workpiece forging includes a temperature that is within the temperature range of the workpiece forging. In a non-limiting embodiment, the workpiece forging temperature range is from 100 ° F (55.6 ° C) below the temperature (T _β ) of the beta transition of the titanium alloy of the workpiece to 700 ° F (388.9 ° C) below the beta transition temperature titanium alloy. According to another non-limiting embodiment, the workpiece forging temperature range is from 300 ° F (166.7 ° C) below the beta transition temperature of the titanium alloy to 625 ° F (347 ° C) below the beta transition temperature of the titanium alloy. According to one non-limiting embodiment, the lower limit of the forging temperature range of the workpiece is the temperature in the two-phase region, and damage, such as, for example, cracking and crumbling on the surface of the workpiece during forging impact, does not occur.

[0062] According to one non-limiting embodiment, shown in FIG. 2 applied to a Ti-6-2-4-2 alloy that has a beta transition temperature (T _β ) of about 1820 ° F (996 ° C), the workpiece forging temperature range may be from 1120 ° F (604.4 ° C) up to 1720 ° F (937.8 ° C) or according to another embodiment, from 1195 ° F (646.1 ° C) to 1520 ° F (826.7 ° C). According to one non-limiting embodiment shown in FIG. 2, applied to a Ti-6-2-4-6 alloy that has a beta transition temperature (T _β ) of about 1720 ° F (940 ° C), the workpiece forging temperature range may be from 1020 ° F (548.9 ° C) up to 1620 ° F (882.2 ° C) or according to another embodiment, from 1095 ° F (590.6 ° C) to 1420 ° F (771.1 ° C). According to yet another non-limiting embodiment shown in FIG. 2 applied to ATI 425 ^® alloy (UNS R54250), which can also be referred to as Ti-4Al-2.5V alloy and which has a beta transition temperature (T _β ) of about 1780 ° F (971.1 ° C ), the forging temperature range of the workpiece can be from 1080 ° F (582.2 ° C) to 1680 ° F (915.6 ° C) or, according to another embodiment, from 1155 ° F (623.9 ° C) to 1480 ° F (804.4 ° C). According to yet another non-limiting embodiment, as applied to that shown in FIG. 2 of an embodiment of the present invention to a Ti-6Al-6V-2Sn alloy (UNS 56620), which may also be referred to as a “Ti-6-6-2" alloy and which has a beta transition temperature (T _β ) of about 1735 ° F ( 946.1 ° C), the forging temperature range of the workpiece can be from 1035 ° F (527.2 ° C) to 1635 ° F (890.6 ° C) or, according to another embodiment, from 1115 ° F (601.7 ° C ) to 1435 ° F (779.4 ° C). The present invention encompasses the use of comprehensive forging with high strain rate and its derivatives, such as the MUD method described in the '538 Application, to titanium alloys that are characterized by slow effective alpha release and growth kinetics, in contrast to Ti-6-4 alloy.

[0063] As shown in FIG. 2 and 3, when the titanium alloy preform 24 is heated to the forging temperature, the preform 24 is subjected to comprehensive forging with a high deformation rate in step (26). According to one non-limiting embodiment of the present invention, comprehensive forging (26) includes the steps of forging (in step 28, as shown in FIG. 3 (a)) the workpiece 24 on the press at the forging temperature in the direction (A) of the first orthogonal axis 30 the workpiece using a strain rate that is sufficient for adiabatic heating of the workpiece or at least adiabatic heating of the inner region of the workpiece and plastic deformation of the workpiece 24.

[0064] High deformation rates and high plunger speeds are used to adiabatically heat the inner region of the workpiece according to non-limiting embodiments of the comprehensive forging with a high deformation rate according to the present invention. According to one non-limiting embodiment of the present invention, the term “high strain rate” refers to a strain rate in the range of from about 0.2 s ⁻¹ to about 0.8 s ⁻¹ . According to another non-limiting embodiment of the present invention, the term "high strain rate" refers to a strain rate in the range of from about 0.2 s ^-1 to about 0.4 s ^-1 .

[0065] In a non-limiting embodiment of the present invention, using the high strain rate as described above, the inner region of the titanium alloy preform can be adiabatically heated to a temperature of about 200 ° F (111.1 ° C) above the forging temperature of the preform. According to another non-limiting embodiment, during forging on a press, the inner region is adiabatically heated to a temperature in the range of about 100 ° F (55.6 ° C) to about 300 ° F (166.7 ° C) above the forging temperature of the workpiece. According to yet another non-limiting embodiment, during forging on a press, the inner region is adiabatically heated to a temperature in the range of about 150 ° F (83.3 ° C) to about 250 ° F (138.9 ° C) above the forging temperature of the workpiece . As indicated above, according to non-limiting embodiments, no part of the preform should be heated above the beta transition temperature of the titanium alloy during the last impact cycle during comprehensive forging of A-B-C with a high deformation rate or during the last impact along the orthogonal axis.

[0066] According to one non-limiting embodiment, during forging on the press in step (28), the workpiece 24 is plastically deformed to precipitate in height or another size, which is in the range from 20% to 50%, i.e. the specified size is reduced by a percentage within the specified range. According to another non-limiting embodiment, during forging on a press in step (28), the workpiece 24 is plastically deformed to precipitate in height or another size in the range from 30% to 40%.

[0067] FIG. 4 schematically illustrates a known all-round forging process with an ultra-slow deformation rate (0.001 s ^-1 or less). In general, the aspect of comprehensive forging is that after each three-way (i.e., “three-hit”) cycle, by means of a forging device (which can be, for example, an open die forging press), the workpiece acquires the shape and size that it had immediately before the first hit of this cycle of three hits. For example, after the first forging hit on a cube-shaped workpiece with a 5 inch (127 mm) rib in the direction of the “a” axis, a 90 ° turn and a second strike in the direction of the “b” orthogonal axis, followed by a 90 ° turn and the forging third impact in the direction of the orthogonal axis "c", the specified workpiece will return to its original cube shape with an edge of approximately 5 inches (127 mm). In other words, despite the fact that a three-stroke cycle deforms the cube in three stages along the three orthogonal axes of the cube, as a result of rearrangement of the specified workpiece between the individual strokes and the choice of draft during each stroke, the total result of the three forging deformations is to return the specified cube to approximately its original shape and size.

[0068] According to another non-limiting embodiment of the present invention, the first press forging step (28) shown in FIG. 2 (a), also referred to in this application as a “first hit”, may include forging a workpiece in a press with a downwardly directed strike on the top to upset the workpiece to a predetermined upset height, while the workpiece is at a temperature in the forging temperature range. As used herein, the term “deposited height” refers to the size of a workpiece after completing a particular upsetting step during forging on a press. For example, to achieve a deposited height of 5 inches (127 mm), the workpiece is forged to a size of about 5 inches (127 mm). In a specific non-limiting embodiment of the method according to the present invention, the upset height is, for example, 5 inches (127 mm). According to another non-limiting embodiment, the upset height is 3.25 inches (82.55 mm). Other upsetting heights, such as, for example, less than 5 inches (127 mm), about 4 inches (101.6 mm), about 3 inches (76.2 mm), more than 5 inches (127 mm), or from 5 inches (127 mm) to 30 inches (762 mm) fall within the scope of protection of the embodiments described herein, but should not be construed as limiting the scope of protection of the present invention. The precipitated heights are limited only by the characteristics of the forging machine and, optionally, as will be seen from the present application, by the characteristics of the thermal management system according to non-limiting embodiments of the present invention, intended to maintain the workpiece at the forging temperature. Precipitated heights less than 3 inches (76.2 mm) also fall within the scope of protection of the embodiments described herein, and such relatively small precipitated heights are limited only by the required characteristics of the finished product. The use of deposited heights of about 30 inches (762 mm), for example, in the methods of the present invention makes it possible to produce billet blanks (for example, with a side 30 inches (762 mm)) in the form of a cube of titanium alloy having a fine grain size, very small size grain or extra fine grain size. Known alloys in cubic form are used as blanks forged by disks, rings and body parts, for example, for aircraft turbines or land turbines.

[0069] The predetermined upsetting heights to be used in various non-limiting embodiments of the methods of the present invention can be determined by one skilled in the art without undue experimentation when considering the present invention. Specified precipitated heights can be determined by a specialist without undue experimentation. Specified precipitated heights depend on the susceptibility of a given alloy to cracking during forging. For alloys that have a higher susceptibility to cracking, increased upsetting heights are required, i.e. reduced impact deformation to prevent cracking. When choosing a precipitated height, the adiabatic heating threshold should also be considered, since at least in the last shock cycle the temperature of the workpiece should not exceed the temperature (T _β ) of the beta transition of the alloy. In addition, when selecting the upsetting height, the limiting characteristics of the forging press must also be taken into account. For example, during the pressing of a cubic blank with a 4 inch (101.6 mm) rib, its cross-sectional area increases during the pressing step. The total load required to deform the workpiece with the required strain rate also increases. The indicated total load cannot exceed the characteristics of the forging press. In addition, when choosing the precipitated heights, the geometry of the workpiece must be taken into account. Increased deformations can lead to bulging of the workpiece. Too much sediment can cause a significant flattening of the workpiece so that the next forging strike in the direction of the other orthogonal axis can cause the workpiece to bend.

[0070] According to some non-limiting embodiments, the upset heights used at each impact along the orthogonal axis are equivalent. In some other non-limiting embodiments, the upset heights used at each impact along the orthogonal axes are not equivalent. Non-limiting embodiments of comprehensive forging with a high deformation rate using nonequivalent upsetting heights for each orthogonal axis are described below.

[0071] After step (28), the forging of the workpiece 24 on the press in the direction of the first orthogonal axis 30, i.e. in the direction A shown in FIG. 2 (a) according to one non-limiting embodiment, the method according to the present invention optionally further includes a step (step 32), wherein the adiabatically heated inner region (not shown) of the preform is cooled to a temperature that is equal to the forging temperature or close to the forging temperature in the range forging temperatures of the workpiece, as shown in FIG. 3 (b). According to various non-limiting embodiments, the cooling times of the inner region or the “waiting times” can be in the range of, for example, from 5 seconds to 120 seconds, from 10 seconds to 60 seconds, or from 5 seconds to 5 minutes. In various non-limiting embodiments, the term “adiabatically heated inner region” of a preform used in this application refers to a region extending outward from the center of the preform and having a volume of at least about 50% or at least about 60%, or at least at least about 70%, or at least about 80% of the volume of the preform. It is obvious for a specialist that the time required to cool the inner region of the preform to a temperature equal to or close to the forging temperature of the preform will depend on the size, shape and composition of the preform 24, as well as on the atmospheric conditions surrounding the preform 24.

[0072] During the cooling period of the inner region, an aspect of the heating control system 33 according to some non-limiting embodiments described herein does not necessarily include heating (at 34) the outer surface region 36 of the workpiece 24 to or near the forging temperature. Thus, the temperature of the workpiece 24 is in homogeneous or close to homogeneous and essentially isothermal conditions at a forging temperature or close to it temperature before each impact in the process of comprehensive forging with a high deformation rate. The specified optional heating (at step 34) of the outer surface region 36 of the workpiece 24 after each impact along the axis A, after each impact along the axis B and / or after each impact along the axis C is considered to be within the protection scope of the present invention. According to various non-limiting embodiments the outer surface of the preform is optionally heated (in step 34) after each cycle of ABC impacts. According to other non-limiting embodiments, the outer surface region is optionally heated after any impact or shock cycle, while the overall temperature of the workpiece during the forging process is maintained within the temperature range of the forging of the workpiece. The time periods during which the workpiece must be heated to maintain the temperature of the workpiece 24 in uniform or close to homogeneous and essentially isothermal conditions at a temperature equal to the temperature of the workpiece forging or close to it, before each impact during comprehensive forging with a high deformation rate can depend on the size of the workpiece and can be determined by a specialist without undue experimentation. According to various non-limiting embodiments of the present invention, the term “outer surface region” of a preform used in this application refers to a region extending inward from the outer surface of the preform and having a volume of at least about 50% or at least about 60%, or at least about 70%, or at least about 80% of the workpiece. It is believed that at any time between ...

[0073] According to non-limiting embodiments, heating (at 34) of the outer surface region 36 of the workpiece 24 can be accomplished using one or more surface-heating mechanisms 38 of the heating control system 33. As possible examples of surface heating before the forging steps on the press, the entire preform can be placed in a furnace or otherwise heated to a temperature in the range of forging temperatures.

[0074] According to some non-limiting embodiments, as an optional feature, between each of the forging strokes A, B, C, a heating control system 33 is used to heat the outer surface region 36 of the workpiece and allow the adiabatically heated inner region to cool during the cooling time of the inner region to return the temperature of the workpiece to a substantially uniform temperature, which is equal to or close to the selected forging temperature of the workpiece. According to some other non-limiting embodiments of the present invention, as an optional feature, between each of the forging strokes A, B and C, a heating control system 33 is used to heat the outer surface region 36 of the workpiece and allow the adiabatically heated inner region to cool during the cooling time of the inner region so that the temperature of the workpiece returns to a substantially uniform temperature that is within the forging temperature range s preparations. Non-limiting embodiments of the method according to the present invention, which used: (1) a heating control system 33 to heat the outer surface region of the workpiece to a temperature within the forging temperature range, and (2) the period during which the adiabatically heated inner region is cooled to temperatures within the temperature range of the forging of the workpiece can be referred to in this application as "thermally controlled all-round forging with a high deformation rate." The surface heating mechanisms 38 include, but are not limited to: flame heaters configured to heat with a flame; induction heaters configured to induction heat; and radiant heaters, adapted to heat radiation from the outer surface of the preform 24. Other mechanisms and methods for heating the outer surface region of the preform will be apparent to those skilled in the art after considering the present invention, and all such mechanisms and methods should be deemed to fall within the protection scope of the present invention. A non-limiting embodiment of a heating mechanism 38 for heating an outer surface area may include a chamber furnace (not shown). The chamber furnace may be configured to use various heating mechanisms to heat the outer surface region of the workpiece using one or more of the flame heating mechanisms, radiant heating mechanisms, induction heating mechanisms, and any other suitable heating mechanism currently known to those skilled in the art or which will become known afterwards.

[0075] According to another non-limiting embodiment, the outer surface region 36 of the workpiece 24 is optionally heated (at step 34) and maintained at a temperature equal to or close to the temperature of the workpiece forging, which is within the temperature range of the workpiece forging, using one or more heaters 40 molds of the heating control system 33. Mold heaters 40 can be used to maintain the temperature of the dies 42 or surfaces 44 of the forging dies on the press equal to or close to the forging temperature, which is within the range of forging temperature of the workpiece. According to one non-limiting embodiment, the dies 42 in the heating control system are heated to a temperature within the range from the forging temperature of the preform to a temperature 100 ° F (55.6 ° C) below the temperature of the forging preform. Mold heaters 40 may heat the dies 42 or the surface of the forging dies 44 on the press using any suitable heating mechanism that is currently known to those skilled in the art or that will be known subsequently, including but not limited to flame heating mechanisms, radiant heating mechanisms, contact heating mechanisms, and / or induction heating mechanisms. According to one non-limiting embodiment, the mold heater 40 may be a component of a chamber furnace (not shown). Although the heating control system 33 is shown in place and used during the cooling steps (32), (52), (60) in the comprehensive forging process (26) shown in FIG. 2 (b), 2 (d) and 2 (f), it should be understood that the heating control system 33 may or may not be present during the forging steps (28), (46), (56) shown in FIG. 2 (a), 2 (c) and 2 (e).

[0076] As shown in FIG. 3 (c), an aspect of a non-limiting embodiment of the all-round forging method (26) according to the present invention comprises forging (at 46) the billet 24 on a press at a billet forging temperature in the billet forging temperature range in the direction (B) of the second orthogonal axis 48 the workpiece 24 using a strain rate sufficient to adiabatically heat the workpiece 24 or at least the inner region of the workpiece 24 and plastic deform the workpiece 24. According to one non-limiting embodiment y implement during forging press on (at step 46), the workpiece 24 is deformed to plastic deformation in the range from 20% to 50% of the precipitation height or other dimension. According to another non-limiting embodiment, during forging on a press (at step 46), the workpiece 24 is plastically deformed for plastic deformation in the range from 30% to 40% of the precipitate in height or another size. According to one non-limiting embodiment, the workpiece 24 may be forged on the press (at step 46) in the direction of the second orthogonal axis 48 to the same upset height used in the first step (28) of the forged press. According to another non-limiting embodiment, the workpiece 24 may be forged on the press in the direction of the second orthogonal axis 48 to the upset height, which differs from that used in the first step (28) of the forging on the press. According to another non-limiting embodiment, the inner region (not shown) of the workpiece 24 is adiabatically heated during the forging in the press to the same temperature as in the first forging step (28) of the press. According to other non-limiting embodiments, the high strain rates used for forging on the press (at step 46) are in the same ranges of strain rates that are described for the first step (28) forging on the press.

[0077] According to one non-limiting embodiment, shown in FIG. 2 (b) and 2 (d), the workpiece 24 can rotate (arrow 50) between subsequent forging steps on the press (for example, steps (28), (46), (56)) to represent various orthogonal axes on the forging surface. Such a rotation may be referred to as an “A-B-C" rotation. It is understood that when using various configurations of the forging machine, it is possible to rotate the press plunger on the forging machine instead of rotating the workpiece 24, or the forging machine can be equipped with multi-axis plungers so that rotation of the workpiece or forging machine is not required. Obviously, an important aspect is the relative change in position of the workpiece and the plunger used, and thus rotation (along arrow 50) of the workpiece 24 may be unnecessary or optional. However, in installations of modern industrial equipment, rotation (along arrow 50) of the workpiece for its orientation with respect to different orthogonal axes between the forging stages on the press is required to complete the comprehensive forging process (26).

[0078] According to non-limiting embodiments that require A-B-C rotation (arrow 50), the workpiece 24 can be manually rotated by the forging machine operator or an automatic rotation system (not shown) that provides A-B-C rotation (arrow 50). The A-B-C automatic rotation system may include, but is not limited to, a self-balancing manipulation tool kit with clamps or the like, to provide a non-limiting thermally-controlled embodiment of the all-round high-speed forging described in this application.

[0079] After forging (at step 46), the workpiece 24 on the press in the direction of the second orthogonal axis 48, i.e. in the direction B, as shown in FIG. 3 (d), method (20) optionally includes steps whereby (at step 52), the adiabatically heated inner region (not shown) of the preform is cooled to a temperature equal to or close to the forging temperature of the preform, as shown in FIG. 3 (d). According to some non-limiting embodiments, the cooling times of the inner region or the waiting times can be in the range of, for example, from 5 seconds to 120 seconds or from 10 seconds to 60 seconds, or from 5 seconds to 5 minutes. For specialists it is obvious that the minimum cooling time depends on the size, shape and composition of the workpiece 24, as well as on the characteristics of the environment surrounding the workpiece.

[0080] During the time period for optional cooling of the inner region, an optional aspect of the heating control system 33 according to some non-limiting embodiments described herein includes the steps of heating (at step 54) the outer surface region 36 of the workpiece 24 to a temperature located in the temperature range of the forging of the workpiece, equal to the temperature of the forging of the workpiece or close to it. Thus, the temperature of the workpiece 24 is maintained under uniform or close to homogeneous and essentially isothermal conditions at a temperature of the workpiece forging or close to it before each impact in the process of comprehensive forging with a high deformation rate. According to various non-limiting embodiments, using a heating control system 33 to heat the outer surface region 36, while allowing the adiabatically heated inner region to cool for a predetermined cooling time of the inner region, the workpiece temperature is returned to a substantially uniform temperature equal to or close to the forging temperature of the workpiece between each forging hit by ABC. According to another non-limiting embodiment of the present invention, by using a heating control system 33 to heat the outer surface region 36, while allowing the adiabatically heated inner region to cool for a predetermined cooling period of the inner region, the workpiece temperature is returned to a substantially uniform temperature within the temperature range forging a workpiece, before each impact, comprehensive forging with a high deformation rate.

[0081] According to one non-limiting embodiment, heating (in step 54) of the outer surface region 36 of the workpiece 24 can be carried out using one or more external surface-heating mechanisms 38 of the heating control system 33. Examples of possible heating mechanisms 38 may include, but are not limited to: flame heaters configured to heat with a flame; induction heaters configured to induction heat; and radiant heaters, configured to heat radiation from the workpiece 24. A non-limiting embodiment of the surface-heating mechanism 38 may include a chamber furnace (not shown). Other mechanisms and methods for heating the outer surface region of the preform will be apparent to those skilled in the art after consideration of the present invention, and all such mechanisms and methods should be deemed to fall within the protection scope of the present invention. A chamber furnace may be configured to use various heating mechanisms to heat the outer surface of the workpiece, and such heating mechanisms may include one or more of flame heating mechanisms, radiant heating mechanisms, induction heating mechanisms, and any other suitable heating mechanism known to those skilled in the art. time or which will become known afterwards.

[0082] According to another non-limiting embodiment, the outer surface region 36 of the workpiece 24 is further heated (at step 54) and maintained at a temperature equal to or close to the temperature of the workpiece forging, which is within the temperature range of the workpiece forging, using one or more heaters 40 molds of the heating control system 33. Mold heaters 40 can be used to maintain the temperature of the dies 42 or surfaces 44 of the forging dies on the press equal to or close to the forging temperature, which is within the range of forging temperature of the workpiece. Mold heaters 40 may heat the dies 42 or the surface of the forging dies 44 on the press using any suitable heating mechanism that is currently known to those skilled in the art or that will be known subsequently, including but not limited to flame heating mechanisms, radiant heating mechanisms, contact heating mechanisms, and / or induction heating mechanisms. According to one non-limiting embodiment, the mold heater 40 may be a component of a chamber furnace (not shown). Although the heating control system 33 is shown in place and used during the balancing and cooling steps (32), (52), (60) during the forging process (26) shown in FIG. 2 (b), 2 (d) and 2 (f), it should be understood that the heating control system 33 may or may not be present during the forging steps (28), (46), (56) shown in FIG. 2 (a), 2 (c) and 2 (e).

[0083] As shown in FIG. 3 (e), an aspect of an embodiment of comprehensive forging (26) according to the present invention includes a step (step 56), according to which the forging of the workpiece 24 is performed on the press at a forging temperature in the temperature range of the forging of the workpiece in the direction (C) of the third orthogonal axis 58 of the workpiece 24 using a plunger speed and a strain rate that are sufficient to adiabatically heat the workpiece 24 or at least adiabatically heat the inner region of the workpiece and plastic deform the workpiece 24. C publicly one non-limiting embodiment, the workpiece 24 is deformed during forging press on (at step 56) for the plastic deformation in the range from 20% to 50% of the precipitation height or other dimension. According to another non-limiting embodiment, during forging on a press (at step 56), the workpiece is plastically deformed for plastic deformation in the range from 30% to 40% of the precipitate in height or another size. According to one non-limiting embodiment, the workpiece 24 can be machined by forging on a press (at step 56) in the direction of the third orthogonal axis 58 to the same deposited height used in the first step (28) of forging on the press and / or second step (46) forging on the press. According to another non-limiting embodiment, the workpiece 24 can be machined by forging on a press in the direction of the third orthogonal axis 58 to a different upset height, different from the height used in the first step (28) of forging on the press. According to another non-limiting embodiment of the present invention, the inner region (not shown) of the workpiece 24 is adiabatically heated during the forging step on the press to the same temperature as that on the first forging step (28) on the press. According to other non-limiting embodiments, the high deformation rates used for forging on the press (at step 56) are in the same ranges of deformation rates that are described for the first stage (28) of forging on the press.

[0084] According to one non-limiting embodiment, as shown by arrow 50 in FIG. 3 (b), 3 (d) and 3 (e), the workpiece 24 can rotate (arrow 50) to the desired orientation of the different orthogonal axis between subsequent forging steps on the press (for example, at steps 46, 56). As described above, such a rotation may be referred to as rotation A-B-C. It is understood that when using various designs of the forging machine, the plunger can be rotated on the forging machine instead of rotating the workpiece 24, or the forging machine can be equipped with multi-axis plungers so that rotation of the workpiece and the forging machine is not required. Thus, rotation in the direction of arrow 50 of the workpiece 24 may be an unnecessary or optional step. However, in installations of modern industrial equipment, rotation (along arrow 50) of the workpiece for its orientation with respect to different orthogonal axes between the forging stages on the press is required to complete the comprehensive forging process (26).

[0085] After forging on the press in step 56 of the workpiece 24 in the direction of the third orthogonal axis 58, i.e. in the direction C, as shown in FIG. 3 (e), method 20 optionally includes steps whereby the adiabatically heated inner region (not shown) of the preform is cooled to a temperature equal to or close to the forging temperature of the preform, as shown in FIG. 3 (f). The cooling times of the inner region can be in the range, for example, from 5 seconds to 120 seconds, from 10 seconds to 60 seconds, or from 5 seconds to 5 minutes, and the specialist understands that the cooling times depend on the size, shape and composition of the workpiece 24, and also on the characteristics of the environment surrounding the workpiece.

[0086] During the optional cooling time period, an optional aspect of the heating control system 33 according to the non-limiting embodiments described herein includes the step of heating (at 62) the outer surface region 36 of the workpiece 24 to a temperature equal to the forging temperature of the workpiece or close to her. Thus, the workpiece 24 is maintained under uniform or close to uniform and essentially isothermal temperature conditions at a temperature equal to or close to the temperature of the workpiece forging before each impact of the comprehensive forging process with a high deformation rate. According to non-limiting embodiments, by using a heating control system 33 to heat the outer surface region 36, while allowing the adiabatically heated inner region to cool for a predetermined cooling time of the inner region, the workpiece temperature is returned to a substantially uniform temperature equal to or close to the forging temperature of the workpiece, between every forging hit ABC. According to another non-limiting embodiment of the present invention, by using a heating control system 33 to heat the outer surface region 36 while allowing the adiabatically heated inner region to cool for a predetermined cooling period of the inner region, the workpiece temperature is returned to substantially isothermal conditions within the workpiece forging temperature range between subsequent forging strokes ABC.

[0087] According to one non-limiting embodiment, heating (in step 62) of the outer surface region 36 of the workpiece 24 can be carried out using one or more external surface-heating mechanisms 38 of the heating control system 33. Examples of possible heating mechanisms 38 may include, but are not limited to: flame heaters configured to heat with a flame; induction heaters configured to induction heat; and / or radiant heaters, adapted to heat radiation from the workpiece 24. Other mechanisms and methods for heating the outer surface region of the workpiece will be apparent to those skilled in the art after consideration of the present invention, and all such mechanisms and methods should be considered to fall within the protection scope of the present invention. One non-limiting embodiment of a surface-heating mechanism 38 may include a chamber furnace (not shown). A chamber furnace may be configured to use various heating mechanisms to heat the outer surface of the workpiece, and such heating mechanisms may include one or more of flame heating mechanisms, radiant heating mechanisms, induction heating mechanisms, and any other suitable heating mechanism known to those skilled in the art. time or which will become known afterwards.

[0088] According to another non-limiting embodiment, the outer surface region 36 of the preform 24 is further heated (at 62) and maintained at a temperature equal to or close to the temperature of the forging preform, which is within the temperature range of the forging of the preform, using one or more heaters 40 molds of the heating control system 33. Mold heaters 40 can be used to maintain the temperature of the dies 42 or surfaces 44 of the forging dies on the press equal to or close to the forging temperature, which is within the range of forging temperature of the workpiece. According to one non-limiting embodiment, the dies 42 in the heating control system are heated to a temperature within the range from the forging temperature of the preform to a temperature 100 ° F (55.6 ° C) below the temperature of the forging preform. Mold heaters 40 may heat the dies 42 or the surface of the forging dies 44 on the press using any suitable heating mechanism that is currently known to those skilled in the art or that will be known subsequently, including but not limited to flame heating mechanisms, radiant heating mechanisms, contact heating mechanisms, and / or induction heating mechanisms. According to one non-limiting embodiment, the mold heater 40 may be a component of a chamber furnace (not shown). Although the heating control system 33 is shown in place and used during the balancing steps (32), (52), (60) in the all-round forging method (26) shown in FIG. 2 (b), 2 (d) and 2 (f), it should be understood that the heating control system 33 may or may not be present during the forging steps 28, 46, 56 of the press shown in FIG. 2 (a), 2 (c) and 2 (e).

[0089] An aspect of the present invention includes a non-limiting embodiment, wherein one or more forging steps on a press along three orthogonal axes of the workpiece is repeated until a total deformation of at least 1.0 is achieved in the workpiece. Total strain is the total true strain. The term “true strain” is also known to those skilled in the art as “logarithmic strain” or “effective strain”. As shown in FIG. 2, in step (g) (step 64), one or more forging steps (28), (46), (56) are repeated forging on the press until a total deformation of at least 1.0 or in the range of at least 1.0 to less than 3.5. In addition, it is believed that after achieving the required deformation at any of the forging steps (28), (46) or (56), additional forging on the press is unnecessary, and the optional balancing steps (i.e., steps (32), ( 52) or (60), on which it is possible to cool the inner region of the preform to a temperature equal to the forging temperature of the preform or a temperature close to it, and steps (34), (54) or (62), on which the outer surface of the preform is heated to a temperature equal to the forging temperature of the workpiece or a temperature close to it) n e are necessary, and the preform can simply be cooled to ambient temperature, or according to one non-limiting embodiment, quenched in liquid, or according to another non-limiting embodiment, cooled by air or by any rapid cooling method.

[0090] It should be understood that, according to one non-limiting embodiment, the total strain is the total strain in the entire workpiece after comprehensive forging, as described in this application. According to non-limiting embodiments of the present invention, the total strain may include equal strains along each orthogonal axis, or the total strain may include various strains on one or more orthogonal axes.

[0091] According to one non-limiting embodiment, after beta annealing, the preform may be subjected to comprehensive forging at two different temperatures in the alpha beta phase region. For example, as shown in FIG. 3, repeating step (64) shown in FIG. 2 may include repeating one or more of steps (a) - (optional b), (c) - (optional d) and (e) - (optional f) at a first temperature in the alpha-beta phase until it is reached some deformation, followed by the repetition of one or more stages (a) - (optional b), (c) - (optional d) and (e) - (optional f) at a second temperature in the alpha-beta phase until until after completion of the final stage (a), (b) or (c) forging in the press (i.e., stage (28), (46), (56)) in the workpiece, a total deformation of at least e 1.0 or deformation in the range of from at least 1.0 to less than 3.5. According to one non-limiting embodiment, the second temperature in the alpha-beta region is lower than the first temperature in the alpha-beta region. The method according to which one or more steps (a) - (optional b), (c) - (optional d) and (e) - (optional f) are repeated at more than two comprehensive forging temperatures on the press should be considered as falling into the scope of protection of the present invention, while temperatures are within the temperature range of the forging. It should also be considered that according to one non-limiting embodiment, the second temperature in the alpha-beta phase region is higher than the first temperature in the alpha-beta phase region.

[0092] According to another non-limiting embodiment of the present invention, various precipitations are used to provide uniform deformation in all directions when pressing along axis A, pressing along axis B, and pressing along axis C. The use of comprehensive forging with a high strain rate to introduce uniform deformation in all directions leads to a reduction in cracking and a more equiaxed structure of the alpha grain in the workpiece. For example, inhomogeneous deformation can be introduced into a cubic billet by forging a cube with an edge of 4 inches (101.6 mm) with a high deformation rate, first along axis A, to a height of 3.0 inches (76.2 mm). This draft along axis A causes the preform to bulge along axis B and axis C. If the second draft in the direction of axis B reduces the size along axis B to 3.0 inches (76.2 mm), a more significant deformation is introduced along the axis B than deformation introduced along axis A. Similarly, a subsequent impact in the direction of axis C to reduce the size of the workpiece along axis C to 3.0 inches (76.2 mm) introduces a more significant deformation along axis C into the workpiece than deformation introduced along axis A or axis B. As another example, for introducing uniform deformation In all orthogonal directions, a 4-inch (101.6 mm) cubic billet is forged (“pressed”) along axis A to a height of 3.0 inches (76.2 mm), rotated 90 ° and pressed along axis B to a height of 3 , 5 inches (88.9 mm), then rotated 90 ° and pressed along the C axis to a height of 4.0 inches (101.6 mm). This last sequence results in a cube having approximately 4 inch ribs and containing uniform deformation in each orthogonal direction. The general equation for calculating the settlement along each orthogonal axis of a cubic billet during comprehensive forging with a high strain rate is presented below as Equation 1.

Equation 1: Deformation = -ln (upset height / reference height).

The general equation for calculating the total strain is presented below as Equation 2.

-ln(осаженная высота/исходная высота).Equation 2: Total strain =

-ln (upset height / reference height).

Different precipitation can be achieved by using backing rings in the forging device that provide different upsetting heights, or in any other way known to the skilled person.

[0093] According to one non-limiting embodiment of the present invention, as shown in FIG. 5 and taking into account FIG. 3, the method (70) for manufacturing an ultrafine titanium alloy includes the steps according to which: beta annealing (at step 71) of the titanium alloy preforms is performed, (after step 72), the preform 24 is cooled to a temperature lower than the temperature of the beta transition of the titanium alloy in the workpiece, heat (at step 73) the workpiece 24 to the forging temperature of the workpiece, which is within the temperature range of the forging of the workpiece, which is within the temperature range of the alpha + beta phase of the titanium alloy of the workpiece, and perform comprehensive forging with a high deformation rate (at step 74) of the workpiece, said comprehensive forging with a high deformation rate (at step 74) includes a sub-step according to which forging is carried out along the orthogonal axes of the workpiece to various upset heights. In one non-limiting embodiment of comprehensive forging (at step 74) according to the present invention, the workpiece 24 is pressed by forging (at step 75) along the first orthogonal axis (axis A) to the main upset height. The phrase "pressed by forging ... to the main upsetting height" used in this application refers to forging a workpiece in a press along an orthogonal axis to the desired final size of the workpiece along a specified orthogonal axis. Thus, the term "major deposited height" refers to the deposited height used to achieve the final workpiece size along each orthogonal axis. All stages of forging on the press to the main precipitated heights must be performed using a strain rate sufficient to adiabatically heat the inner region of the workpiece.

[0094] After forging (at step 75) the workpiece 24 on the press in the direction of the first orthogonal axis A to the main upsetting height, as shown in FIG. 3 (a), method (70) optionally further includes a step according to which the adiabatically heated inner region (not shown) of the preform is allowed to cool (at step 76 shown in FIG. 3 (b)) to a temperature equal to or close to the forging temperature of the preform To her. The cooling times of the inner region can be, for example, in the range from 5 seconds to 120 seconds, from 10 seconds to 60 seconds, or from 5 seconds to 5 minutes, and one skilled in the art will appreciate that the required cooling times depend on the size, shape and composition of the workpiece, and also on the characteristics of the environment surrounding the workpiece.

[0095] During the time period for optional cooling of the inner region, an aspect of the heating control system 33 according to the non-limiting embodiments described herein may include the step of heating (in step 77) the outer surface region 36 of the workpiece 24 to a temperature equal to the forging temperature blanks or close to it. Thus, the billet 24 is supported under uniform or close to uniform temperature and essentially isothermal conditions at a forging temperature of the billet or a temperature close to it before each impact of comprehensive forging with a high deformation rate. According to some non-limiting embodiments, by using the heating control system 33 to heat the outer surface region 36, while allowing the adiabatically heated inner region to cool for a predetermined cooling time of the inner region, the workpiece temperature returns to a substantially uniform temperature equal to or close to forging temperature temperature, between each of the forging strokes A, B and C. According to other non-limiting options, real According to the present invention, as a result of using the heating control system 33 to heat the outer surface region 36 while allowing the adiabatically heated inner region to cool during the indicated cooling time of the inner region, the workpiece temperature returns to a substantially uniform temperature within the workpiece forging temperature range between each from forging strokes A, B and C.

[0096] According to one non-limiting embodiment, heating (at step 77) of the outer surface region 36 of the workpiece 24 can be carried out using one or more external surface-heating mechanisms 38 of the heating control system 33. Examples of possible mechanisms 38 heating the outer surface include, but are not limited to: flame heaters configured to heat with a flame; induction heaters configured to induction heat; and radiant heaters, configured to heat radiation from the workpiece 24. Other mechanisms and methods for heating the outer surface region of the workpiece will be apparent to those skilled in the art after consideration of the present invention, and all such mechanisms and methods should be considered to be within the protection scope of the present invention. One non-limiting embodiment of a surface-heating mechanism 38 may include a chamber furnace (not shown). A chamber furnace may be configured to use various heating mechanisms to heat the outer surface of the workpiece, and such heating mechanisms may include one or more of flame heating mechanisms, radiant heating mechanisms, induction heating mechanisms, and any other suitable heating mechanism known to those skilled in the art. time or which will become known afterwards.

[0097] According to another non-limiting embodiment, the outer surface region 36 of the workpiece 24 can be heated (at step 34) and maintained at a temperature equal to or close to the temperature of the workpiece forging, using one or more heaters 40 of the mold of the heating control system 33. Mold heaters 40 can be used to maintain the temperature of the dies 42 or surfaces 44 of the forging dies on the press equal to or close to the forging temperature, which is within the range of forging temperature of the workpiece. According to one non-limiting embodiment, the dies 42 in the heating control system are heated to a temperature within the range from the forging temperature of the preform to a temperature 100 ° F (55.6 ° C) below the temperature of the forging preform. Mold heaters 40 may heat the dies 42 or the surface of the forging dies 44 on the press using any suitable heating mechanism that is currently known to those skilled in the art or that will be known subsequently, including but not limited to flame heating mechanisms, radiant heating mechanisms, contact heating mechanisms, and / or induction heating mechanisms. According to one non-limiting embodiment, the mold heater 40 may be a component of a chamber furnace (not shown). Although the heating control system 33 is shown in place and used during the cooling steps in a comprehensive forging process, it should be understood that the heating control system 33 may or may not be present in place during the forging steps on the press.

[0098] According to one non-limiting embodiment, after forging on the press to the main upsetting height (in step 75) along axis A (as shown in FIG. 3), which is also referred to in this application as “draft A”, and after optional clearance steps cooling (at step 76) and heating (at step 77), if these steps are applied, the subsequent forging steps on the press to block the deposited heights, which may contain optional heating and cooling steps, are applied along the B and C axes to "round off" the workpiece ( return st We blank square form). The phrase “forging on the press to block the deposited height” in this application means forging on the press to the first upset blocked by a washer ring (in steps (78), (87), (96)) and forging on the press to be blocked by the deposited height using a washer ring heights (at steps (81), (90), (99)), which are defined as the forging stage on the press, used to reduce or "round off" the bulging that occurs in the central region of any surface after forging on the press to the main upset height. The buckling in the center or near the center of any surface leads to a volumetric stress state created in the surfaces, which can lead to cracking of the workpiece. The steps of forging on the press to the first upsetting height and forging on the press to the second upsetting, also referred to in this application as the first blocked sludge, second blocked sludge, or simply as blocked sludge, are used to deform the protruding surfaces so that the workpiece surfaces are flat or essentially flat before the next forging on the press to the main upsetting height along the orthogonal axis. The stages of blocked upsetting include forging on the press to the upset height, which is greater than the upset height used at each stage of forging on the press to the main upset height. Although the strain rate for all of the first and second blocked sediments described in this application may be sufficient for adiabatic heating of the inner region of the workpiece, according to one non-limiting embodiment, adiabatic heating during the first and second blocked sediments may not be observed, since the total deformation created in the first and second blocked sediments is probably insufficient for a noticeable adiabatic heating of the workpiece. Since blocked precipitation is performed up to precipitated heights that are greater than those used in forging on a press to the main precipitated height, the deformation introduced into the workpiece at the stage of blocked precipitation may not be sufficient for adiabatic heating of the inner region of the workpiece. As will be seen later, the combination of the first and second blocked precipitates during comprehensive forging with a high deformation rate according to one non-limiting embodiment leads to a forging sequence in at least one forging cycle consisting of forging operations: A -BC- B -CA- C , moreover, forging operations A , B and C include forging on the press to the main upsetting height, and forging operations B, C, C and A include forging on the press for upsetting to the first or second blocked deposited heights; or according to another non-limiting embodiment, at least one cycle consists of forging operations: A -BC- B -CA- C -AB, and forging operations A , B and C include forging on the press to the main upsetting height, and forging operations B, C, C, A, A and B include forging on the press to the first or second blocked upsetting height.

[0099] As shown in FIG. 3 and 5, according to one non-limiting embodiment, after the forging step on the press to the main upset height (at step 75) along the first orthogonal axis (draft A ) and, if applied, after optional steps of allowing to cool (at step 76) and heat (at step 77), as described above, the workpiece is pressed by forging (at step 78) along axis B to the first blocked deposited height. Although the strain rate of the first blocked upset may be sufficient to adiabatically heat the inner region of the workpiece, according to one non-limiting embodiment, adiabatic heating during the first blocked upset may not be observed, since the deformation introduced during the first blocked upset may not be sufficient for noticeable adiabatic heating of the workpiece. Optionally, it is possible to cool (at step 79) the adiabatically heated inner region of the preform to a temperature equal to or close to the forging temperature of the preform, while the outer surface region of the preform is heated (at 80) to a temperature equal to or close to the forging temperature of the preform To her. All cooling times and heating methods for precipitation A (at step 75) described above and in other embodiments of the present invention are suitable for steps (79) and (80) and to all optional subsequent steps in which it is possible to cool the inner region of the workpiece and heating the outer surface region of the preform.

[0100] Then, the workpiece is subjected to the next forging in the press (at step 81) along axis C for blocked upsetting to a second deposited height that is greater than the main deposited height. The first and second blocked precipitation is used to return the preform substantially to its shape before forging. Although the strain rate of the second blocked upset may be sufficient to adiabatically heat the inner region of the workpiece, according to one non-limiting embodiment, adiabatic heating during the second blocked upset may not be observed, since the deformation introduced during the second blocked upset may be insufficient for noticeable adiabatic heating of the workpiece. Optionally, they provide (at 82) the ability to cool the adiabatically heated inner region of the preform to a temperature equal to or close to the forging temperature of the preform, while the outer surface region of the preform is heated (at 83) to a temperature equal to or close to the forging temperature of the preform To her.

[0101] Then, the workpiece is subjected to the next forging on the press (at step 84) in the direction of the second orthogonal axis, or axis B, for upsetting to the main upsetting height. Press forging for upsetting to the main upsetting height along axis B (at step 84) is referred to herein as draft B. After precipitation B (at step 84), it is not necessarily possible (at step 85) to cool the adiabatically heated inner region of the preform to a temperature equal to or close to the forging temperature of the preform, while the outer surface region of the preform is heated (at step 86) to a temperature equal to the forging temperature of the workpiece or close to it.

[0102] Then, the workpiece is subjected to the next forging on the press (at step 87) along the C axis for blocked upsetting to the first deposited height, which is greater than the main deposited height. Although the strain rate of the first blocked upset may be sufficient to adiabatically heat the inner region of the workpiece, according to one non-limiting embodiment, adiabatic heating during the first blocked upset may not be observed, since the deformation introduced during the first blocked upset may not be sufficient for noticeable adiabatic heating of the workpiece. Optionally, provide (at 88) the ability to cool the adiabatically heated inner region of the preform to a temperature equal to or close to the forging temperature of the preform, while the outer surface region of the preform is heated (at 89) to a temperature equal to or near the forging temperature of the preform To her.

[0103] Then, the workpiece is subjected to the next forging on the press (at step 90) along axis A for blocked upsetting to a second deposited height that is greater than the main deposited height. The first and second blocked precipitation is used to return the preform substantially to its shape before forging. Although the strain rate of the second blocked upset may be sufficient to adiabatically heat the inner region of the workpiece, according to one non-limiting embodiment, adiabatic heating during the second blocked upset may not be observed, since the deformation introduced during the second blocked upset may be insufficient for noticeable adiabatic heating of the workpiece. Optionally, it is possible (at step 91) to cool the adiabatically heated inner region of the preform to a temperature equal to or close to the forging temperature of the preform, while the outer surface region of the preform is heated (at 92) to a temperature equal to or close to the forging temperature of the preform To her.

[0104] Then, the workpiece is subjected to the next forging on the press (at step 93) in the direction of the third orthogonal axis, or axis C, for upsetting to the main upsetting height. Forging press for upsetting to main osazhennoy height along the axis C (in step 93) is designated herein as a precipitate C. After precipitation C (at step 93), it is not necessarily possible (at step 94) to cool the adiabatically heated inner region of the preform to a temperature equal to or close to the forging temperature of the preform, while the outer surface region of the preform is heated (at 95) to a temperature equal to the forging temperature of the workpiece or close to it.

[0105] Then, the workpiece is subjected to the next forging on the press (at step 96) along axis A for blocked upsetting to the first deposited height, which is greater than the main deposited height. Although the strain rate of the first blocked upset may be sufficient to adiabatically heat the inner region of the workpiece, according to one non-limiting embodiment, adiabatic heating during the first blocked upset may not be observed, since the deformation introduced during the first blocked upset may not be sufficient for noticeable adiabatic heating of the workpiece. Optionally, provide (at step 97) the ability to cool the adiabatically heated inner region of the preform to a temperature equal to or close to the forging temperature of the preform, while the outer surface region of the preform is heated (at step 98) to a temperature equal to the forging temperature of the preform or close To her.

[0106] Then, the workpiece is subjected to the next forging on the press (at step 99) along axis B for blocked upsetting to a second deposited height that is greater than the main deposited height. The first and second blocked precipitation is used to return the preform substantially to its shape before forging. Although the strain rate of the second blocked upset may be sufficient to adiabatically heat the inner region of the workpiece, according to one non-limiting embodiment, adiabatic heating during the second blocked upset may not be observed, since the deformation introduced during the second blocked upset may be insufficient for noticeable adiabatic heating of the workpiece. Optionally, they provide (at 100) the ability to cool the adiabatically heated inner region of the preform to a temperature equal to or close to the forging temperature of the preform, while the outer surface region of the preform is heated (at 101) to a temperature equal to or near the forging temperature of the preform To her.

[0107] As shown in FIG. 5, according to non-limiting embodiments, one or more of the steps (75), (78), (81), (84), (87), (90), (93), (96) and (99) forging on the press is repeated (at step 102) until a degree of total deformation of the titanium alloy in said preform is achieved of at least 1.0. According to another non-limiting embodiment, one or more of the steps (75), (78), (81), (84), (87), (90), (93), (96) and (99) forging on the press is repeated ( at step 102) until the total strain in the range of at least 1.0 to less than 3.5 is reached in the titanium alloy preform. It should be understood that after achieving the required deformation of at least 1.0, or according to another embodiment of the desired deformation in the range from at least 1.0 to less than 3.5 at any of the steps (75), (78), ( 81), (84), (87), (90), (93), (96) and (99) forging on the press are optional intermediate stages of balancing (i.e., steps (76), (79), (82) , (85), (88), (91), (94), (97) or (100), according to which it is possible to cool the inner region of the workpiece, and steps (77), (80), (83), (86 ), (89), (92), (95), (98) or (101), on which the outer surface of the workpiece is heated) are not necessary, and the workpiece can be cooled to ambient temperature. In one non-limiting embodiment, cooling includes quenching in a liquid, such as, for example, quenching in water. According to another non-limiting embodiment, cooling includes cooling at a cooling rate of air flow or faster cooling.

[0108] The process described above involves re-forging the press for upsetting to the main upsetting height, followed by forging in the press for locked upsetting to the first and second upset heights. The forging sequence, which is one complete comprehensive forging cycle described above in the non-limiting embodiment, can be represented as forging operations A -BC- B -CA- C -AB, with operations (strokes) that are indicated in bold and underlined, designed for precipitation to the main precipitated height, and operations that are not indicated in bold and not underlined are the first or second blocked precipitation. It should be understood that all forging upsetting on the press, including forging operations on the press for upsetting to the main upsetting heights, as well as the first and second blocked precipitations of the comprehensive forging process according to the present invention are performed with a high deformation rate sufficient to adiabatically heat the inner region of the workpiece, and for example, and without limitation, the strain rate is in the range from 0.2 s ^-1 to 0.8 s ^-1 or in the range from 0.2 s ^-1 to 0.4 s ^-1 . It should also be understood that adiabatic heating may not essentially occur during the first and second blocked sediments due to the reduced degree of deformation during these precipitation compared to the main precipitation. It should also be understood that between successive forging deposits, as optional, there are stages in which the adiabatically heated inner region of the workpiece is cooled to a temperature equal to or close to the forging temperature of the workpiece, and on which the outer surface of the workpiece is heated to a temperature equal to the forging temperature of the workpiece or close to it, using the heating control system described in this application. It is believed that these optional steps may be more preferable when using the method according to the present invention for processing workpieces having large dimensions. Additionally, it is understood that the forging sequence A -BC- B -CA- C -AB according to the embodiment described herein can be repeated in whole or in part until the degree of total deformation in the workpiece is at least 1.0 or in the range of at least least 1.0 to less than 3.5.

[0109] Bulging in a preform is the result of a combination of a blocking by the die surface and the presence of hotter material in the center of the preform. With increasing buckling, the center of each surface is exposed to increasing volumetric loads, which can initiate cracking. In the sequence A -BC- B -CA- C -AB, the use of blocked deposits between each forging operation in the press to settle to the main upsetting height reduces the tendency to crack formation in the workpiece. According to one non-limiting embodiment, if the preform is in the form of a cube, the first blocked draft to the first deposited height can be made up to the deposited height, which is 40-60% more than the main deposited height. According to one non-limiting embodiment, if the preform is in the form of a cube, a second blocked draft to the second deposited height can be made up to the deposited height, which is 15-30% more than the main deposited height. According to another non-limiting embodiment, the first deposited height with a blocked draft can be substantially equivalent to the second deposited height with a blocked draft.

[0110] In non-limiting embodiments of thermally controlled all-round forging with a high deformation rate according to the present invention, after total deformation to a degree of at least 1.0, or in the range of at least 1.0 to less than 3.5, the average alpha grain size particles in the preform is 4 μm or less, which is believed to be ultrafine grain size (UFG). According to one non-limiting embodiment of the present invention, applying a total strain of at least 1.0, or in the range of at least 1.0 to less than 3.5, allows the formation of grains that are equiaxed.

[0111] According to one non-limiting embodiment of the method according to the present invention, including comprehensive forging and the use of an optional heating control system, the working surface of the stamping blank of the press is lubricated with known lubricants, such as, but not limited to, graphite, glass grease, and / or other known greases.

[0112] According to some non-limiting embodiments of the methods of the present invention, the preform comprises a titanium alloy selected from biphasic alpha-beta titanium alloys and metastable beta titanium alloys. According to another non-limiting embodiment, the preform comprises a two-phase titanium alloy with an alpha beta structure. According to yet another non-limiting embodiment, the preform comprises a metastable beta-titanium alloy. According to one non-limiting embodiment, the titanium alloy processed by the method of the present invention has an effective alpha phase separation and growth kinetics that are slower than the kinetics of the Ti-6-4 alloy (UNS R56400), and such kinetics may be designated in this application as "slower alpha kinetics." According to one non-limiting embodiment, slower alpha kinetics can be achieved if the diffusion ability of the most slowly diffusing constituent particles in a titanium alloy is slower than the diffusion ability of aluminum in a Ti-6-4 alloy at a beta transition temperature (T _β ). For example, Ti-6-2-4-2 alloy has slower alpha kinetics than Ti-6-4 alloy, due to the presence of additional grain-retaining elements, such as silicon, in Ti-6-2-4-4 alloy . In addition, the Ti-6-2-4-6 alloy has a slower alpha kinetics than the Ti-6-4 alloy, as a result of the presence of additional beta-stabilizing additives in the alloy, such as molybdenum, the content of which in this alloy is higher than in alloy T-6-4. The result of slower alpha kinetics in these alloys is that beta annealing of Ti-6-2-4-6 and Ti-6-2-4-2 alloys before comprehensive forging with a high deformation rate makes it possible to achieve a relatively small and stable the size of the alpha packet and the fine structure of the beta phase compared with the Ti-6-4 alloy and some other titanium alloys having faster alpha phase separation and growth kinetics than Ti-6-2-4-6 and Ti alloys -6-2-4-2. The expression "slower alpha kinetics" is described in detail above in this application. Examples of titanium alloys that can be processed using embodiments of the methods of the present invention include, but are not limited to, Ti-6-2-4-2 alloy, Ti-6-2-4-6 alloy, ATI 425 ^® alloy (Ti alloy 4Al-2.5V), Ti-6-6-2 alloy and Ti-6Al-7Nb alloy.

[0113] A non-limiting embodiment of the method according to the present invention includes beta annealing steps, according to which: the preform is heated to beta annealing temperature, the preform is kept at beta annealing temperature for a period of time sufficient to form a microstructure with 100% beta phase of titanium in the workpiece, and cool the workpiece directly to a temperature equal to or close to the forging temperature of the workpiece. In some non-limiting embodiments, the beta annealing temperature is in the temperature range from the beta transition temperature of the titanium alloy to a temperature that is 300 ° F (111 ° C) higher than the beta transition temperature of the titanium alloy. According to non-limiting embodiments, the beta annealing time is from 5 minutes to 24 hours. After reading the present description it will be clear to a person skilled in the art that other beta annealing temperatures and beta annealing times also fall within the protection scope of the embodiments of the present invention, and, for example, relatively large preforms may require relatively higher beta annealing temperatures and / or longer beta annealing times for the formation of a 100% titanium beta phase microstructure.

[0114] According to some non-limiting embodiments, in which the preform is supported at a beta annealing temperature to form a microstructure with a 100% beta phase, the preform can also be plastically deformed at a plastic deformation temperature in the beta phase region of the titanium alloy before cooling the preform to a temperature equal to the forging temperature of the workpiece or close to it, or to ambient temperature. Plastic deformation of the workpiece may contain at least one of hoods, forging by upset and all-round forging with a high speed of deformation of the workpiece. According to one non-limiting embodiment, the plastic deformation in the beta phase region includes forging of the preform by upsetting until the degree of deformation as a result of precipitation in the beta phase region is achieved in the range from 0.1 to 0.5. According to some non-limiting embodiments, the temperature of plastic deformation is in the temperature range of plastic deformation from the temperature of the beta transition of the titanium alloy to a temperature 300 ° F (111 ° C) above the beta transition temperature of the titanium alloy, inclusive.

[0115] In FIG. 6 shows the temperature-time graph of thermomechanical processing in a non-limiting way of plastic deformation of the workpiece above the beta transition temperature and direct cooling to the forging temperature of the workpiece. As shown in FIG. 6, the non-limiting method 200 includes a step 202 in which a preform of a titanium alloy having alpha release and growth kinetics that are slower than that of a Ti-6-4 alloy is heated, for example, to a temperature of 204 beta annealing, which is higher than temperature 206 the transition of the titanium alloy, and step 208, at which the workpiece is held or "languished" at a temperature of 204 beta-annealing to form the microstructure completely with the beta phase of titanium in the workpiece. According to one non-limiting embodiment of the present invention, after languishing in step 208, the preform may be plastically deformed in step 210. According to one non-limiting embodiment, the plastic deformation step 210 includes forging by sludge. According to one non-limiting embodiment, the plastic deformation step 210 includes forging by upset to a true deformation of 0.3. According to one non-limiting embodiment, the plastic deformation step 210 includes thermally controlled all-round forging with a high deformation rate (not shown in FIG. 6) at beta annealing temperature.

[0116] As shown in FIG. 6, after plastic deformation 210 in the beta phase region according to one non-limiting embodiment, the preform is cooled in step 212 to a forging temperature 214 of the preform in the alpha + beta phase region of the titanium alloy. According to one non-limiting embodiment, the cooling in step 212 comprises cooling with a cooling rate of air flow or faster cooling. According to another non-limiting embodiment, cooling includes quenching in a liquid, such as, for example, quenching in water. After cooling, in step 212, the workpiece is subjected to comprehensive forging at a high strain rate temperature 214 according to some non-limiting embodiments of the present invention. According to one non-limiting embodiment, as shown in FIG. 6, the workpiece is hit or forged on the press 12 times, i.e. along the three orthogonal axes, the workpieces are inconsistently forged on the press a total of 4 times along each axis. In other words, as shown in FIG. 2 and 6, a cycle including steps (a) - (optional b), (c) - (optional d) and (e) - (optional f) is performed 4 times. According to one non-limiting embodiment, as shown in FIG. 6, after a comprehensive forging sequence of 12 strokes, the total deformation may be equal to, for example, at least 1.0, or may range from at least 1.0 to less than 3.5. After comprehensive forging in step 214, the workpiece is cooled in step 216 to ambient temperature. According to one non-limiting embodiment, cooling in step 216 includes cooling with an airflow cooling rate or faster cooling, but other forms of cooling, such as, but not limited to, quenching in a fluid or liquid, also fall within the protection scope of the embodiments of the present invention described herein application.

[0117] A non-limiting aspect of the present invention includes comprehensive forging with a high deformation rate at two temperatures in the alpha + beta phase region. In FIG. 7 shows a temperature-time graph of thermomechanical processing in a non-limiting manner according to the present invention, comprising the steps of performing comprehensive forging of a titanium alloy preform at the first forging temperature of the preform, optionally using the non-limiting embodiment of the thermal control means described above, cooling to a second preform forging temperature in the field of alpha + beta phases, comprehensive forging of the titanium alloy billet is performed at the second forging temperature agotovki and optionally use a non-limiting embodiment of means for teprmoupravleniya described herein.

[0118] As shown in FIG. 7, the non-limiting method 230 according to the present invention includes the steps of heating the preform in step 232 to a beta annealing temperature 234 that is higher than the alloy beta transition temperature 236 and holding or tearing the preform in step 238 at a beta annealing temperature 234 to form a titanium alloy preform of a microstructure entirely consisting of a beta phase. After languishing at step 238, the preform may be plastically deformed at step 240. According to one non-limiting embodiment, plastic deformation at step 240 includes forging by upset. According to another non-limiting embodiment, plastic deformation in step 240 includes forging by upset to a strain of 0.3. According to another non-limiting embodiment, the plastic deformation of the preform at step 240 includes comprehensive forging with a high deformation rate (not shown in FIG. 7) at beta annealing temperature.

[0119] As shown in FIG. 7, after plastic deformation in step 240 in the beta phase region, the workpiece is cooled in step 242 to a first workpiece forging temperature 244 in the alpha + beta phase of the titanium alloy. In non-limiting embodiments, cooling in step 242 includes one of air cooling and quenching in a liquid. After cooling, in step 242, the preform is subjected to comprehensive forging in step 246 with a high deformation rate at the first forging temperature of the preform, and the heating control system according to the non-limiting embodiments described herein is optionally used. According to one non-limiting embodiment shown in FIG. 7, the workpiece is hit or forged in the press at the first forging temperature of the workpiece 12 times with a 90 ° rotation between strokes, i.e. along three orthogonal axes, the workpiece is forged on the press 4 times along each axis. In other words, as shown in FIG. 2, a cycle including steps (a) - (optional b), (c) - (optional d) and (e) - (optional f) is performed 4 times. According to one non-limiting embodiment, as shown in FIG. 7, after comprehensively forging the preform with a high deformation rate in step 246 at the first forging temperature, the titanium alloy preform is cooled in step 248 to a second forging temperature of the preform in step 250 in the alpha + beta phase region. After cooling, in step 248, the preform is subjected to comprehensive forging 250 with a high deformation rate at a second forging temperature of the preform, and the heating control system is optionally used according to the non-limiting embodiments described herein. According to one non-limiting embodiment, as shown in FIG. 7, the workpiece is hit or forged on the press at a second forging temperature of the workpiece for a total of 12 times. It should be understood that the number of strokes on a titanium alloy preform at the first and second forging temperatures of the preform can be changed depending on the required true deformation and the desired final grain size, and the number of strokes, which is suitable, can be determined without undue experimentation after considering the present inventions. After comprehensive forging in step 250, at a second forging temperature, the workpiece is cooled in step 252 to ambient temperature. In non-limiting embodiments, cooling in step 252 includes one of air cooling and quenching in a liquid to ambient temperature.

[0120] According to one non-limiting embodiment, the first forging temperature of the preform is in the first forging temperature range from a temperature that is more than 100 ° F (55.6 ° C) lower than the beta transition temperature of the titanium alloy to a temperature that is 500 ° F (277.8 ° C) below the beta transition temperature of the titanium alloy, i.e. first temperature T_one forging workpiece is in the range: T_β-100 ° F> T_one≥T_β-500 ° F. In one non-limiting embodiment, the second forging temperature of the preform is in the second forging temperature range from a temperature that is more than 200 ° F (277.8 ° C) lower than the beta transition temperature of the titanium alloy to a temperature that is 700 ° F (388 , 9 ° C) below the beta transition temperature, i.e. second temperature T₂ forging blanks is in the range: T_β-200 ° F> T₂≥T_β-700 ° F. According to one non-limiting embodiment, the titanium alloy preform comprises an alloy Ti-6-2-4-4; the first workpiece temperature is 1650 ° F (898.9 ° C); and a second workpiece forging temperature is 1500 ° F (815.6 ° C).

[0121] In FIG. 8 shows a temperature-time graph of thermomechanical processing in a non-limiting manner according to the present invention for plastic deformation of a workpiece, including heating a titanium alloy to a temperature higher than the beta transition temperature and cooling the workpiece to a forging temperature while using thermally controlled all-round forging of a workpiece with a high deformation rate according to non-limiting implementation options described in this application. As shown in FIG. 8, a non-limiting method 260 of using thermally controlled all-round forging with a high deformation rate for grinding grain of a titanium alloy includes the steps of heating the preform in step 262 to a beta annealing temperature 264, which is higher than the beta transition temperature 266 of the titanium alloy, and holding it or simmering step 268 the preform at a temperature of 264 beta annealing to form in the preform a microstructure entirely consisting of a beta phase. After languishing at 268 at a beta annealing temperature, the workpiece is plastically deformed at 270. According to one non-limiting embodiment, plastic deformation at 270 may include thermally controlled all-round forging with a high deformation rate. According to one non-limiting embodiment, the preform is subjected to repeated comprehensive forging in step 272 with a high deformation rate using the optional heating control system described above in this application to cool the preform below the beta transition temperature. In FIG. 8 shows three intermediate stages of comprehensive forging with a high deformation rate 272, but it should be understood that, if necessary, more or fewer intermediate stages of comprehensive forging with a high deformation rate can be used. The intermediate stages of comprehensive forging with a high deformation rate 272 are located between the initial stage 270 of comprehensive forging with a high rate of deformation at a temperature of heat and the final stage 274 of comprehensive forging with a high rate of deformation in the alpha + beta phase of the titanium alloy. Despite the fact that in FIG. Figure 8 shows one final stage of comprehensive forging with a high deformation rate, at which the temperature of the workpiece remains completely in the alpha + beta phase, after reading the present description it will be clear that for additional processing of grain in the alpha + beta phase, two and more stages of comprehensive forging. According to non-limiting embodiments of the present invention, at least one final stage of comprehensive forging with a high deformation rate is carried out completely at temperatures in the alpha + beta phase region of the titanium alloy preform.

[0122] Since comprehensive forging steps 270, 272, 274 are performed while the workpiece is cooled to temperatures below the beta transition temperature of the titanium alloy, the method according to one embodiment shown in FIG. 8, is referred to in this application as "comprehensive forging with a high strain rate at the intersection of the beta transition." According to one non-limiting embodiment, a heating control system 33 (as shown in FIG. 3) is used for all-round forging with a beta transition intersection to maintain the workpiece at a uniform or substantially uniform temperature before each impact at each forging temperature with a beta intersection and, optionally to slow down the cooling rate. After the final comprehensive forging step 274, which is performed at the forging temperature of the preform in the alpha + beta phase region, the preform is cooled in step 276 to ambient temperature. According to one non-limiting embodiment, the cooling in step 276 includes air cooling.

[0123] Non-limiting embodiments of comprehensive forging using the heating control system described above can be used to process titanium alloy preforms having cross sections greater than 4 square meters. inches (25.8 cm ² ), using known forging equipment, and the size of the blanks having a cubic shape can be scaled to match the characteristics of a particular press. It has been determined that alpha-lamellae or packets of a β-annealed structure easily crumble to a fine, uniform alpha grain at the forging temperatures of the preform according to the non-limiting embodiments described herein. It was also determined that lowering the forging temperature of the preform leads to a decrease in alpha particle size (grain size).

[0124] Without going deeper into specific theories, it is contemplated that grain processing, which takes place in non-limiting embodiments of thermally controlled all-round forging with a high deformation rate according to the present invention, occurs through metadynamic recrystallization. In the well-known all-round forging process with a low deformation rate, dynamic recrystallization occurs instantly during deformation of the material. It is contemplated that in comprehensive forging with a high deformation rate according to the present invention, metadynamic recrystallization occurs at the end of each deformation or each forging impact, despite the fact that at least the inner region of the workpiece is hot as a result of adiabatic heating. Residual adiabatic heat, cooling times of the inner region and heating of the outer surface region affect the degree of grain processing in non-limiting embodiments of thermally controlled all-round forging with a high deformation rate according to the present invention.

[0125] Alternative methods have been further developed according to the present invention, providing several advantages over the method described above, including comprehensive forging using a heating control system and a cube-shaped workpiece containing a titanium alloy. It is assumed that at least one of (1) the cubic geometry of the workpiece used in some embodiments of the thermally controlled all-round forging described in this application is (2) cooling the die (i.e., allowing the die temperature to be significantly lower than the forging temperature of the workpiece) and (3) the use of high strain rates can lead to an undesirable concentration of strain in the central region of the workpiece.

[0126] Alternative methods according to the present invention can contribute to the achievement of a generally uniform fine grain, very fine grain or ultra-fine grain size over the entire volume of the titanium alloy long-sized billet. In other words, the workpiece processed by such alternative methods may have the required grain size, such as ultrafine grain, over the entire volume of the workpiece, and not just in its central region. Non-limiting embodiments of such alternative methods include the steps of "multiple upsetting and drawing" applied to workpieces having cross sections greater than 4 square meters. inches (25.8 cm ² ). The multiple steps of precipitation and drawing are designed to create a microstructure with a uniform fine grain, very fine grain or ultrafine grain throughout the workpiece while preserving essentially the original dimensions of the workpiece. Since such alternative methods include multiple steps of settling and drawing, they are indicated in this application as embodiments of the method of multiple settling and drawing (MUD). The method of multiple precipitation and drawing (MUD) involves intensive plastic deformation and allows the formation of uniform ultrafine grains in billets of long size (for example, 30 inches (76.2 cm) long) from a titanium alloy. According to non-limiting embodiments of the multiple draft and draw (MUD) method according to the present invention, the indicated strain rates used in the forging by draft and drawing forging are in the range from 0.001 s ^-1 to 0.02 s ^-1 . In contrast, the strain rates commonly used in the known open die forging and draft forging steps are in the range of 0.03 s ⁻¹ to 0.1 s ⁻¹ . The strain rate during repeated upsetting and drawing is slow enough to prevent adiabatic heating of the workpiece while maintaining the forging temperature under control, but the specified strain rate is acceptable for commercial applications.

[0127] A schematic representation of non-limiting embodiments of the multiple draft and draw (MUD) method is shown in FIG. 9, and a flow chart of some embodiments of the multiple draft and draw (MUD) method is shown in FIG. 10. As shown in FIG. 9 and 10, a non-limiting method 300 for grinding grains in a preform containing a titanium alloy using forging steps with multiple upsetting and drawing, includes the step of heating an elongated preform 302 of titanium alloy forging in the alpha + beta phase of the titanium alloy . According to one non-limiting embodiment, the elongated preform has a cylinder shape or a shape similar to that of a cylinder. According to another non-limiting embodiment, the preform is in the form of an octahedron or regular octagon.

[0128] The elongated preform has an initial cross section. For example, according to one non-limiting embodiment, the multiple draft and draw method according to the present invention, in which the initial preform is a cylinder, the initial cross-sectional size is the diameter of the cylinder. According to one non-limiting embodiment, the multiple upsetting and drawing (MUD) method according to the present invention, in which the initial preform is an octahedron, the initial transverse dimension is the diameter of a circle describing an octagonal cross section, i.e. the diameter of a circle that passes through all the vertices of an octagonal cross section.

[0129] When the elongated preform is at a forging temperature of the preform, the preform is forged by draft at step 304. After forging by draft at step 304 according to one non-limiting embodiment, the preform is rotated 90 ° to reach orientation 306 and then subjected to multi-pass forging by hood at step 312. Actual rotation of the workpiece is optional, and the task of this step is to position the workpiece in the correct orientation (as shown in Fig. 9) relative to the forging device, followed by multi-pass to a hood in step 312.

[0130] Multipass hood forging includes incremental rotation (shown by arrow 310) of the workpiece in the direction of rotation (indicated by arrow 310), followed by forging in step 312 of the workpiece after each increment of rotation. In non-limiting embodiments, incremental rotation in step 310 and forging by hood in step 312 are repeated until the workpiece returns to its original transverse dimension. According to one non-limiting embodiment, the steps of forging by draft and multi-pass forging by hood are repeated until a total deformation of at least 1.0 is achieved in the workpiece. Another non-limiting embodiment includes repeating the steps of heating, draft forging, and multi-pass forging by hood, until the total deformation in the range of at least 1.0 to less than 3.5 is achieved in the workpiece. According to yet another non-limiting embodiment, the steps of heating, draft forging, and multi-pass forging by hood are repeated until a total deformation of at least 10 is achieved in the workpiece. It is expected that as a result of forging by multiple draft and drawing in the workpiece, a total deformation of 10 is achieved in the workpiece an ultrafine-grained alpha microstructure is formed, and an increase in the total strain introduced into the preform results in a decrease in the average grain size.

[0131] According to one aspect of the present invention, a deformation rate that is sufficient to cause severe plastic deformation of the titanium alloy preform should be used during the upsetting and multi-pass drawing steps, which according to non-limiting embodiments further leads to the formation of ultrafine grains. According to one non-limiting embodiment, the strain rate used in the forging by sludge is in the range from 0.001 s ^-1 to 0.003 s ^-1 . According to another non-limiting embodiment, the strain rate used in the multi-pass hood forging steps is in the range of 0.01 s ^-1 to 0.02 s ^-1 . The '538 Application describes that deformation rates in these ranges do not lead to adiabatic heating of the workpiece, which makes it possible to control the temperature of the workpiece and is a sufficient basis for economically acceptable commercial practice.

[0132] According to one non-limiting embodiment, upon completion of the multiple settlement and drawing (MUD) method, the preform has substantially the initial dimensions of the original elongated product, such as, for example, cylinder 314 or octahedron 316. According to another non-limiting embodiment, after completion of the multiple settlement method and hoods (MUD) the preform has substantially the same cross section as the original preform. According to one non-limiting embodiment, a single draft requires that multiple blow strokes and intermediate rotations return the workpiece to a shape having an original cross-section of the workpiece.

[0133] According to one non-limiting embodiment, a multiple upsetting and drawing (MUD) method, in which the workpiece, for example, has the shape of a cylinder, incremental rotation and exhaust forging further include the multiple steps of rotating the cylindrical workpiece in increments of 15 ° followed by forging an exhaust, until the cylindrical workpiece rotates 360 ° with a forged hood at each increment. According to one non-limiting embodiment, the multiple draft and draw (MUD) method, in which the workpiece is in the form of a cylinder, after each forging by the draft, to bring the workpiece substantially to its original transverse size, twenty-four stages of forging by hood are used with an intermediate rotation in increments between successive stages of forging extractor hood. According to another non-limiting embodiment, in which the workpiece is in the form of an octagonal cylinder, incremental rotation and hood forging further include the multiple steps of rotating the cylindrical workpiece in 45 ° increments and forging the hood, until the cylindrical workpiece rotates 360 ° with the forging hood at each increment. According to one non-limiting embodiment, the multi-upsetting and drawing (MUD) method, in which the preform is in the form of an octahedron, after each forging by the draft to bring the preform substantially to its initial transverse size, eight forging steps are used, separated by rotation in incremental steps. In non-limiting embodiments of the multiple draft and draw (MUD) method, it was noted that manipulating an octahedron with handling equipment was more accurate than manipulating a cylinder with handling equipment. It was also noted that the handling of the octahed by loading and unloading equipment according to one non-limiting embodiment of the multiple draft and draw (MUD) method turned out to be more accurate than the manipulation of a cube-shaped workpiece using hand-held tongs according to the non-limiting options for implementing the thermally-controlled all-round forging method with high strain rate described in this application. It should be understood when considering the present description that other hood forging sequences, each of which may contain many stages of hood forging and intermediate rotations in increments of a specific number of degrees, can be used for workpieces having other cross-sectional shapes, so that the final shape preforms after forging by hood are essentially the same as the original form of the preform forging by draft. These other possible sequences can be determined by a person skilled in the art without undue experimentation and should be construed as falling within the protection scope of the present invention.

[0134] According to one non-limiting embodiment of the multiple settling and drawing (MUD) method of the present invention, the workpiece forging temperature includes a temperature within the workpiece forging temperature range. According to one non-limiting embodiment, the workpiece forging temperature is in the temperature range from a temperature 100 ° F (55.6 ° C) lower than the temperature (T _β ) of the beta transition of the titanium alloy to a temperature 700 ° F (388.9 ° C) lower beta transition temperature of titanium alloy. According to another non-limiting embodiment, the workpiece forging temperature is in the temperature range from 300 ° F (166.7 ° C) below the titanium alloy beta transition temperature to 625 ° F (347 ° C) below the beta transition temperature of titanium alloy . According to one non-limiting embodiment, the lower end of the workpiece forging temperature range is a temperature in the alpha + beta phase region at which substantially no damage to the workpiece surface occurs during forging impact, as can be determined without undue experimentation by a person skilled in the art.

[0135] According to one non-limiting embodiment of the multiple precipitation and drawing (MUD) method according to the present invention, the temperature range of forging a preform for a Ti-6-2-4-2 alloy that has a beta transition temperature (T _β ) of about 1820 ° F ( 993.3 ° C), can be, for example, from 1120 ° F (604.4C) to 1720 ° F (937.8 ° C), or according to another non-limiting embodiment, from 1195 ° F (646.1 ° C) to 1520 ° F (826.7 ° C).

[0136] Non-limiting embodiments of the multiple settling and drawing (MUD) method include multiple reheating steps. According to one non-limiting embodiment, the titanium alloy preform is heated to the forging temperature of the preform after forging by pre-forging the titanium alloy preform. According to another non-limiting embodiment, the titanium alloy preform is heated to the forging temperature of the preform before the forging step of a multi-pass forging by hood. According to another non-limiting embodiment, the preform is heated if necessary to return the actual temperature of the preform to a temperature close to the temperature of forging the preform after the step of forging by draft or forging by hood.

[0137] it Was determined that the implementation of the method of multiple precipitation and drawing (MUD) lead to the performance of excessive work or the creation of excessive deformation, which can also be called intense plastic deformation, which is aimed at creating ultrafine grains in the workpiece containing a titanium alloy. Without delving into a specific theory of operation, it is assumed that the circular or octagonal cross-sectional shape of cylindrical and octagonal cylindrical blanks, respectively, contributes to a more uniform strain distribution than the strain distribution in blanks having a square or rectangular cross-sectional shape over the entire cross-sectional area of the workpiece during multiple precipitation and drawing (MUD) treatments. The undesirable effect of friction between the workpiece and the forging die is also reduced by reducing the contact area of the workpiece when interacting with the die.

[0138] It was further further determined that a decrease in temperature during processing by multiple precipitation and drawing (MUD) methods reduces the final grain size to a size that is characteristic of a given temperature used. As shown in FIG. 10, according to one non-limiting embodiment of a method 400 for grinding grain size of a workpiece after processing said workpiece by multiple precipitation and drawing (MUD) at a forging temperature, said workpiece can be cooled in step 416 to a second forging temperature of the workpiece. According to one non-limiting embodiment, after cooling the workpiece to a second forging temperature, the specified workpiece is forged by upsetting at step 418 at a second workpiece forging temperature. At step 420, the workpiece is rotated or otherwise oriented relative to the forging press to perform the subsequent stages of forging by hood. At 422, multiple stretching forging steps are applied to the workpiece at a second forging temperature of the workpiece. The multi-stage hood forging at the second forging temperature of the workpiece in step 422 includes incremental rotation in step 424 of the workpiece in the direction of rotation (as shown in FIG. 9) and hood forging at the second forging temperature in step 426 after each rotation increment. According to one non-limiting embodiment, the steps of upsetting, incremental rotation in step 424, and hood forging in step 426 are repeated until the workpiece returns to its original transverse dimension. According to another non-limiting embodiment, the steps of forging with draft at the second temperature of the workpiece at step 418, rotation at step 420, and multiple forging by hood at step 422 are repeated until the total strain in the workpiece is at least 1.0 or a strain in the range from 1.0 to less than 3.5, or up to 10 or more. It is believed that the multiple precipitation and drawing method (MUD) can be continued until any necessary total deformation is imparted to the titanium alloy preform.

[0139] According to one non-limiting embodiment, comprising an embodiment of a multi-temperature multiple draft and draw (MUD) method, the workpiece forging temperature, or the first workpiece forging temperature, is about 1600 ° F (871.1 ° C), and the second workpiece forging temperature is approximately 1,500 ° F (815.6 ° C). Subsequent billet forging temperatures that are lower than the first and second billet forging temperatures, such as a third billet forging temperature, a fourth billet forging temperature, and the like, fall within the protection scope of non-limiting embodiments of the present invention.

[0140] As forging is performed, grain refinement reduces the stress of plastic flow at a fixed temperature. It was determined that a decrease in the forging temperature for successive stages of precipitation and drawing maintains the plastic flow stress constant and increases the rate of microstructural grinding. It is expected that according to non-limiting embodiments of multiple draft and draw (MUD) according to the present invention, the total deformation to a degree of at least 1.0, in the range from at least 1.0 to less than 3.5, or to a degree of 10 results to a uniform equiaxed ultrafine-grained alpha microstructure in titanium alloy preforms, and the lower temperature in the multiple precipitation and drawing (MUD) method with two temperatures (or multiple temperatures) can be determined from the final grain size after attaching the blanks A total strain to a degree of 10 during forging by multiple draft and draw (MUD).

[0141] An aspect of the present invention includes the ability to perform subsequent deformation steps after processing a workpiece by multiple precipitation and drawing (MUD) without enlarging the crushed grain size, until the workpiece temperature is heated above the beta transition temperature of the titanium alloy after processing. For example, according to one non-limiting embodiment, the deformation steps subsequent to the multiple settlement and drawing (MUD) process may include forging by hood, multiple forging by hood, forging by draft, or any combination of two or more of these forging methods at temperatures in the alpha + beta region phases of titanium alloy. According to one non-limiting embodiment, the subsequent deformation or forging steps include a combination of multi-pass forging, draft forging and draft forging to reduce the initial transverse dimension similar to a cylinder or having a different elongated workpiece to a fraction of the transverse dimension, such as, for example, but not limited to half transverse size, one quarter of transverse size, etc., while maintaining a homogeneous structure of fine grain, very fine grain or ultrafine th grain in a titanium alloy billet.

[0142] According to one non-limiting embodiment of the multiple precipitation and drawing (MUD) method, the preform comprises a titanium alloy selected from the group consisting of alpha + beta titanium alloy and metastable beta titanium alloy. According to another non-limiting embodiment of the multiple precipitation and drawing method (MUD), the preform comprises an alpha + beta titanium alloy. According to yet another non-limiting embodiment of the multiple precipitation and drawing method described herein, the preform comprises a metastable beta titanium alloy. According to one non-limiting embodiment of the multiple precipitation and drawing method (MUD), the preform comprises a titanium alloy selected from a Ti-6-2-4-4 alloy, a Ti-6-2-4-6 alloy, an ATI 425 ^® alloy (Ti-4Al -2.5V) and Ti-6-6-2 alloy.

[0143] Before heating the preform to the forging temperature of the preform in the alpha + beta phase according to embodiments of the multiple precipitation and drawing (MUD) method according to the present invention, in a non-limiting embodiment, the preform can be heated to beta annealing temperature, kept at beta annealing for a period of beta annealing sufficient to form a microstructure with a 100% beta phase of titanium in the preform and cooled to ambient temperature. In one non-limiting embodiment, the beta annealing temperature is in the range of beta annealing temperatures from the beta transition temperature of the titanium alloy to a temperature that is 300 ° F (111 ° C) higher than the beta transition temperature of the titanium alloy. According to one non-limiting embodiment, the beta annealing time is from 5 minutes to 24 hours.

[0144] According to one non-limiting embodiment, the preform is an ingot, all or some of whose surfaces are coated with a lubricating coating that reduces friction between the preform and the forging dies. According to one non-limiting embodiment, the lubricating coating is a grease, including but not limited to one of graphite and glass lubricant. Other lubricating coatings currently known or which will be known subsequently fall within the protection scope of the present invention. In addition, according to one non-limiting embodiment of the multiple draft and draw (MUD) method, which uses cylinder-like or other elongated preforms, the contact area between the preform and the forging dies is small compared to the contact area for all-round forging of the preform having the form Cuba. For example, in the case of a cube with a 4-inch (101.6 mm) rib, two of all 4x4-inch (101.6 x 101.6 mm) cube surfaces are in contact with the die. In the case of an ingot 5 feet (1520 mm) long, the ingot is longer than the length of a typical 14 inch (350 mm) die, and a decrease in contact area leads to a reduction in the friction of the die and a more uniform microstructure and macrostructure of the titanium alloy billet.

[0145] Before heating a preform containing a titanium alloy to the forging temperature of the preform in the alpha + beta phase according to embodiments of the multiple precipitation and drawing (MUD) method according to the present invention, according to one non-limiting embodiment, the preform is plastically deformed at a plastic deformation temperature in the region of the beta phase of the titanium alloy while maintaining for a time of beta annealing sufficient to form a 100% beta phase in the titanium alloy, and before cooling Ava to ambient temperature. According to one non-limiting embodiment, the temperature of plastic deformation is equal to the temperature of beta annealing. According to another non-limiting embodiment, the temperature of plastic deformation is in the temperature range of plastic deformation from the beta transition temperature of the titanium alloy to a temperature that is 300 ° F (111 ° C) higher than the beta transition temperature of the titanium alloy.

[0146] According to one non-limiting embodiment of the multiple precipitation and drawing (MUD) method, plastic deformation of a workpiece at temperatures in the beta phase region of a titanium alloy includes at least one of drawing, draft forging and all-round forging with a high deformation rate of a titanium alloy workpiece. According to another non-limiting embodiment, plastic deformation of the preform at temperatures in the beta phase region of the titanium alloy involves repeated forging by draft and drawing according to non-limiting embodiments of the present invention, and cooling the preform to a temperature equal to or close to the forging of the preform includes air cooling. According to yet another non-limiting embodiment, plastic deformation of the preform at temperatures in the beta phase region of the titanium alloy involves forging the preform up to a draft of 30-35% of height or another size, such as length.

[0147] Another aspect of the multiple draft and draw (MUD) method of the present invention may include heating the forging dies during forging. A non-limiting embodiment includes heating the dies of the forging machine used for forging the workpiece to a temperature in the temperature range from the temperature of the forging of the workpiece to a temperature that is 100 ° F (55.6 ° C) lower than the temperature of the forging of the workpiece.

[0148] According to non-limiting embodiments of the multiple precipitation and drawing (MUD) method according to the present invention, the method for manufacturing ultrafine titanium alloys includes the steps of: selecting a titanium alloy having slower alpha release and growth kinetics than Ti-6 alloy -4, perform beta-annealing of the alloy to provide a fine-grained and stable structure of the alpha package and perform comprehensive forging of the alloy with a high deformation rate according to the present invention to total strain ii at least 1.0, or to a degree ranging from at least 1.0 to less than 3.5. The titanium alloy can be selected from alpha + beta-titanium alloys and metastable beta-titanium alloys, which provide a fine-grained and stable structure of the alpha package after beta annealing.

[0149] It is contemplated that some of the methods described herein can also be applied to metals and metal alloys in addition to titanium alloys to reduce grain size in preforms of these alloys. Another aspect of the present invention comprises non-limiting embodiments of a multi-stage forging process with a high deformation rate of metals and metal alloys. A non-limiting embodiment of this method includes heating a preform containing a metal or metal alloy to a forging temperature of the preform. After heating, the preform is forged at the forging temperature of the preform with a strain rate sufficient to adiabatically heat the inner region of the preform. After forging, a waiting period is used before the next forging step. During the specified waiting period, it is possible to cool the adiabatically heated inner region of the metal alloy preform to the forging temperature of the preform by heating at least one surface region of the preform to the temperature of the preform forging. The steps of forging a workpiece and subsequently making it possible to balance the adiabatically heated inner region of the workpiece to a temperature of forging a workpiece by heating at least one surface region of a workpiece of metal alloy to a temperature of forging a workpiece is repeated until the desired characteristics are obtained. According to one non-limiting embodiment, the forging comprises at least one of forging on a press, forging by upset, forging by hood and forging by rolling. According to another non-limiting embodiment, the metal alloy is selected from the group consisting of titanium alloys, zirconium and zirconium alloys, aluminum alloys, iron alloys and superalloys. According to yet another non-limiting embodiment, the desired characteristic is at least one of the imparted strain, average grain size, shape and mechanical properties. Mechanical properties include, but are not limited to, strength, ductility, fracture toughness, and hardness,

[0150] The examples below are intended to further describe some non-limiting embodiments without limiting the scope of protection of the present invention. One skilled in the art will appreciate that possible changes to the following examples fall within the scope of protection of the present invention as defined in the appended claims.

EXAMPLE 1

[0151] A bar of Ti-6-2-4-2 alloy was processed by a known forging method designated by industry standard AMS 4976, which is commonly used to process Ti-6-2-4-4 alloy. From the AMS 4976 standard, the specialist will understand the specific features of the process of achieving the mechanical properties and microstructure described in this standard. After processing, the alloy was prepared metallographically, and its microstructure was carefully evaluated. As shown in the micrograph of the prepared alloy shown in FIG. 11 (a), the microstructure contains alpha grains (lightly colored areas in the image) that are about 20 μm or larger in size.

[0152] According to a non-limiting embodiment of the present invention, a 4.0-inch (101.6 mm) cube-shaped preform of Ti-6-2-4-2 alloy is beta annealed at a temperature of 1950 ° F (1066 ° C) for 1 hour and then cooled in air to ambient temperature. After cooling, the cube-shaped beta-billet was heated to a forging temperature of 1600 ° F (871.1 ° C) and forged using four impacts by a comprehensive forging with a high deformation rate. Impacts were performed in the direction of the following orthogonal axes and in the following sequence: ABCA. As a result of the impacts, a deposited height of 3.25 inches (88.9 mm) was achieved, and the plunger speed was 1 inch per second (25.4 mm / s). There was no control of the strain rate on the press, but for cubes with a 4.0 inch (101.6 mm) rib, such a plunger speed leads to a minimum strain rate during pressing of 0.25 s ^-1 . The time between subsequent orthogonal impacts was approximately 15 seconds. The degree of total deformation attached to the workpiece was 1.37. The microstructure of the Ti-6-2-4-2 alloy thus treated is shown in the micrograph of FIG. 11 (b). Most of the alpha particles (light colored areas) have a size of the order of 4 microns or less, which is essentially finer grain than the alpha grain made by the known forging method described above and shown in the micrograph in FIG. 11 (a).

EXAMPLE 2

[0153] A bar of Ti-6-2-4-6 alloy was processed by a known forging method commonly used for T-6-2-4-6 alloy, i.e. according to the standard AMS 4981. From the standard AMS 4976 the specialist will understand the specific features of the process of achieving the mechanical properties and microstructure set forth in this standard. After processing, the alloy was prepared metallographically, and its microstructure was carefully evaluated. As shown in the micrograph of the finished alloy in FIG. 12 (a), the microstructure contains alpha grains (light colored areas) that are of the order of 10 microns or larger.

[0154] According to one non-limiting embodiment of the present invention, a 4.0-inch (101.6 mm) cube-shaped preform of Ti-6-2-4-6 alloy was beta annealed at a temperature of 1870 ° F (1066 ° C) ) for 1 hour and then cooled in air. After cooling, the cube-shaped beta-billet was heated to a forging temperature of 1500 ° F (815.6 ° C) and forged using four impacts using a comprehensive forging method with a high deformation rate. Impacts were performed in the direction of the following orthogonal axes and in the following sequence: ABCA. As a result of the impacts, a deposited height of 3.25 inches (88.9 mm) was achieved, and the plunger speed was 1 inch per second (25.4 mm / s). There was no control of the strain rate on the press, but for cubes with a 4.0 inch (101.6 mm) rib, such a plunger speed leads to a minimum strain rate during pressing of 0.25 s ^-1 . The time between subsequent orthogonal impacts was approximately 15 seconds. The degree of total deformation attached to the workpiece was 1.37. The microstructure of the alloy thus treated is shown in the micrograph of FIG. 12 (b). It can be seen that most of the alpha particles (light colored areas) are of the order of 4 microns or smaller and in any case are much finer grains than alpha grains made by the known forging method described above and shown in the micrograph on FIG. 12 (a).

EXAMPLE 3

[0155] According to one non-limiting embodiment of the present invention, a 4.0-inch (101.6 mm) cube-shaped preform of Ti-6-2-4-6 alloy was beta annealed at a temperature of 1870 ° F (1066 ° C) ) for 1 hour and then cooled in air. After cooling, the cube-shaped beta-billet was heated to the forging temperature of 1500 ° F (815.6 ° C) and forged using three impacts by the comprehensive forging method with a high deformation rate with one impact along each axis A, B and C (i.e. e. Impacts were carried out in the direction of the following orthogonal axes and in the following sequence: ABC). As a result of the impacts, a deposited height of 3.25 inches (88.9 mm) was achieved, and the plunger speed was 1 inch per second (25.4 mm / s). There was no control of the strain rate on the press, but for cubes with a 4.0 inch (101.6 mm) rib, such a plunger speed leads to a minimum strain rate during pressing of 0.25 s ^-1 . The time between subsequent orthogonal impacts was approximately 15 seconds. After a cycle of ABC strokes, the workpiece was reheated to a temperature of 1500 ° F (815.6 ° C) for 30 minutes. Then, the cubic billet was subjected to comprehensive forging with a high deformation rate with one impact along each of the axes A, B, and C, i.e. impacts were performed along the following orthogonal axes and in the following sequence: ABC. As a result of the strokes, the same settled height was achieved, and the same plunger speed and the time between strokes were used as in the first sequence of ABC strokes. After a second sequence of ABC strokes, the workpiece was reheated to a temperature of 1500 ° F (815.6 ° C) for 30 minutes. Then, the cubic billet was subjected to comprehensive forging with a high deformation rate with one impact along each of the axes A, B, and C, i.e. the ABC sequence was used. As a result of the strokes, the same settled height was achieved, and the same plunger speed and the time between strokes were used as in the first sequence of ABC strokes. As a result of this embodiment of the method of comprehensive forging with a high deformation rate, the workpiece was given a strain of 3.46. The microstructure of the alloy thus treated is shown in the micrograph of FIG. 13. It can be seen that most of the alpha particles (light colored areas) are of the order of 4 microns or less. It is assumed that, in all likelihood, the alpha particles are composed of individual alpha grains, and that each alpha grain has a size of the order of 4 μm or less and is equiaxial in shape.

EXAMPLE 4

[0156] According to one non-limiting embodiment of the present invention, a 4.0-inch (101.6 mm) cube preform of Ti-6-2-4-2 alloy was beta annealed at a temperature of 1950 ° F (1066 ° C) ) for 1 hour and then cooled in air. After cooling, the cube-shaped beta-preform was heated to a forging temperature of 1700 ° F (926.7 ° C) and held for 1 hour. Two comprehensive forging cycles with a high deformation rate were used (2 sequences of three ABC strokes totaling 6 strokes) at a temperature of 1700 ° F (926.7 ° C). The time between successive strokes was approximately 15 seconds. The forging sequence was as follows: Punch A using a 3-inch (76.8 mm) limiter; punch B using a 3.5-inch (89.6 mm) limiter; and punch C using a 4.0-inch (102.4 mm) limiter. This forging sequence provides equal deformation along all three orthogonal axes in each three-impact comprehensive forging sequence. The plunger speed was 1 inch per second (25.4 mm / s). There was no control of the strain rate on the press, but for cubes with a 4.0 inch (101.6 mm) rib, such a plunger speed leads to a minimum strain rate during pressing of 0.25 s ^-1 . The total strain per cycle was less than forging to a 3.25-inch (83.2 mm) draft in each direction, as in the previous examples.

[0157] The billet was heated to a temperature of 1650 ° F (898.9 ° C) and subjected to comprehensive forging with a high deformation rate by performing three additional strokes (ie, one additional round A-B-C comprehensive forging with a high deformation rate). The forging sequence was as follows: Punch A using a 3-inch (76.8 mm) limiter; punch B using a 3.5-inch (89.6 mm) limiter; and punch C using a 4.0-inch (102.4 mm) limiter. After forging, the total deformation imparted to the workpiece was 2.59.

[0158] The microstructure of the forged billet from Example 4 is shown in the micrograph of FIG. 14. It can be seen that most of the alpha particles (light colored areas) form a network structure. It is assumed that, in all likelihood, the alpha particles are composed of individual alpha grains, and that each alpha grain has a size of the order of 4 μm or less and is equiaxial in shape.

EXAMPLE 5

[0159] According to one non-limiting embodiment of the present invention, a 4.0-inch (101.6 mm) cube-shaped preform of Ti-6-2-4-2 alloy was beta annealed at a temperature of 1950 ° F (1066 ° C) ) for 1 hour and then cooled in air. After cooling, the cube-shaped beta-preform was heated to a forging temperature of 1700 ° F (926.7 ° C) and held for 1 hour. The comprehensive forging according to the present invention was used for applying to the cube-shaped preform 6 forges on a press to upset to the main upset height ( A , B , C , A , B , C ). In addition, to “round off” the workpiece between each forging on the upsetting press to a major upsetting height of 3.25 inches (82.55 mm), the first and second blocked precipitations were performed along other axes. The following general forging sequence was used, in which forging on the press for upsetting to the main upsetting height is indicated in bold and underlined symbols: A -BC- B -CA- C -AB- A -BC- B -CA- C .

[0160] The forging sequence, including used primary, first blocked and second blocked upset (in inches), is shown in the table below. The plunger speed was 1 inch per second (25.4 mm / s). There was no control of the strain rate on the press, but for cubes with a 4.0 inch (101.6 mm) rib, such a plunger speed leads to a minimum strain rate during pressing of 0.25 s ^-1 . The time elapsed between strokes was approximately 15 seconds. The degree of total deformation after thermally controlled all-round forging according to this non-limiting embodiment was 2.37.

Axes and upsetting heights (in inches) Hit A B C one 3.25 2 4.25 3 4.25 four 3.25 5 4.75 6 four 7 3.25 8 4.75 9 four 10 3.25 eleven 4.75 12 four 13 3.25 fourteen 4.75 fifteen four 16 3.25 Total strain 2,37

 [0161] The microstructure of the preform forged by the method described in Example 5 is shown in the micrograph of FIG. 15. It can be seen that most of the alpha particles (light colored areas) are elongated. It is assumed that, in all likelihood, the alpha particles are composed of individual alpha grains, and that each alpha grain has a size of the order of 4 μm or less and is equiaxial in shape.

EXAMPLE 6

[0162] In one non-limiting embodiment of the present invention, a 4.0-inch (101.6 mm) cube-shaped preform of Ti-6-2-4-2 alloy was beta annealed at a temperature of 1950 ° F (1066 ° C) ) for 1 hour and then cooled in air. Then, thermally controlled all-round forging with a high deformation rate was applied to the workpiece according to the embodiments of the present invention, including 6 strokes (2 ABC comprehensive forging cycles) at a temperature of 1900 ° C with 30-second pauses between strokes. The plunger speed was 1 inch per second (25.4 mm / s). There was no control of the strain rate on the press, but for cubes with a 4.0 inch (101.6 mm) rib, such a plunger speed leads to a minimum strain rate during pressing of 0.25 s ^-1 . A sequence of 6 strokes with intermediate pauses was intended to heat the surface of the workpiece with the beta-transition temperature crossing during comprehensive forging, which in this application can thus be called “comprehensive forging with a high deformation rate with beta-crossing intersection”. This method leads to the grinding of surface structures and minimize cracking during subsequent forging. The preform was then heated to 1650 ° F (898.9 ° C), i.e. below the beta transition temperature, and kept for 1 hour. Then, comprehensive forging was applied to the workpiece according to embodiments of the present invention, containing 6 strokes (two ABC comprehensive forging cycles) with approximately 15 second pauses between strokes. The first three strokes (strokes in the first ABC all-round forging) were performed to the upset height of 3.5 inches (88.9 mm), and the second 3 strokes (strokes in the second ABC all-round forging) were made to the upset height of 3.25 inches (82.55 mm). The preform was heated to a temperature of 1650 ° F and held for 30 minutes between strokes with a 3.5-inch (88.9 mm) washer ring and strokes with a 3.25-inch (82.55 mm) washer ring. The reduced sediment (i.e., the increased deposited height) used for the first 3 strokes was designed to block cracking, since the reduced precipitate destroys the boundary structures that can lead to cracking. The preform was then reheated to 1500 ° F (815.6 ° C) and held for 1 hour. Then, comprehensive forging was applied to the workpiece according to the embodiments of the present invention using 3 strokes of ABC (one cycle of comprehensive forging) with draft up to a height of 3.25 inches (82.55 mm) with 15-second pauses between strokes. Such a sequence with increased precipitation is intended for additional work in non-boundary structures. The plunger speed for all the strokes described in Example 6 was 1 inch per second (25.4 mm / s).

[0163] In Example 6, the workpiece was attached to a total strain of 3.01. A representative micrograph of the central part of the preform after thermally controlled all-round forging in Example 6 is shown in FIG. 16 (a). A representative micrograph of the surface region of the workpiece after thermally controlled all-round forging in Example 6 is shown in FIG. 16 (b). The surface microstructure (as shown in Fig. 16 (b)) is significantly crushed and most of the particles and / or grains have a size of about 4 μm or less, which is an ultrafine-grained microstructure. The microstructure of the central part shown in FIG. 16 (a) shows very fine grains, and it is assumed that, in all probability, the alpha particles are composed of individual alpha grains, and that each alpha grain has a size of the order of 4 μm or less and is equiaxial in shape.

[0164] It should be understood that the present description provides aspects of the invention corresponding to a clear understanding of the present invention. Some aspects that are obvious to specialists and which, therefore, do not contribute to an improved understanding of the present invention, are not presented in this application to simplify the present description. Despite the fact that only a limited number of embodiments of the present invention are described in this application, specialists, after considering the above description, will agree that many modifications and variations of the present invention are possible. All such changes and modifications of the present invention are intended to cover the protection scope of the present invention in accordance with the above description and the appended claims.

Claims (62)

1. The method of grinding grain size of a workpiece containing a titanium alloy, including: beta annealing of the workpiece; cooling the beta-annealed preform to a temperature below the beta transition temperature of the titanium alloy; and comprehensive forging of the workpiece, and comprehensive forging includes: forging a workpiece in a press at a temperature of forging a workpiece in the temperature range of forging a workpiece in the direction of the first orthogonal axis of the workpiece with a strain rate sufficient to adiabatically heat the inner region of the workpiece, forging a workpiece in a press at a temperature of forging a workpiece located in the temperature range of forging a workpiece in the direction of the second orthogonal axis of the workpiece with a strain rate sufficient to adiabatically heat the inner region of the workpiece, forging a workpiece in a press at a temperature of forging a workpiece in the temperature range of forging a workpiece in the direction of the third orthogonal axis of the workpiece with a strain rate sufficient to adiabatically heat the inner region of the workpiece, and the repetition of at least one of the forgings on the press until the total true deformation in the workpiece is at least 1.0, wherein the workpiece forging temperature is in the range from a temperature 100 ° F (55.6 ° C) below the beta transition temperature of the titanium alloy to 700 ° F (388.9 ° C) lower than the beta transition temperature of the titanium alloy, and the deformation rate used during forging on the press is in the range from 0.2 s ^-1 to 0.8 s ^-1 . 2. The method according to p. 1, characterized in that at least one of the forgings on the press is repeated until the total true deformation in the workpiece is achieved in the range from at least 1.0 to less than 3.5. 3. The method according to p. 1, characterized in that the preform contains one of an alpha + beta titanium alloy or metastable beta titanium alloy. 4. The method according to p. 3, characterized in that the titanium alloy contains at least one of the grain-stopping alloying additives or beta-stabilizing additives effective to reduce the release of the alpha phase and the kinetics of the growth of the alpha phase. 5. The method according to p. 1, characterized in that the preform contains a titanium alloy selected from alloy Ti-6Al-2Sn-4Zr-6Mo (UNS R56260), alloy Ti-6Al-2Sn-4Zr-2Mo-0.08Si (UNS R54620), Ti-4Al-2.5V alloy (UNS R54250), Ti-6Al-7Nb alloy (UNS R56700) and Ti-6Al-6V-2Sn alloy (UNS R56620). 6. The method according to p. 1, characterized in that the cooling of the beta-annealed preform includes cooling the preform to ambient temperature. 7. The method according to p. 1, characterized in that the cooling of the beta-annealed preform includes cooling the preform to a temperature equal to or close to the forging temperature of the preform. 8. The method according to p. 1, characterized in that the beta annealing of the workpiece includes heating the workpiece to a temperature of beta annealing in the range from the temperature of the beta transition of the titanium alloy to a temperature 300 ° F (167 ° C) above the beta transition temperature of the alloy titanium. 9. The method according to p. 1, characterized in that the beta-annealing of the workpiece includes heating the workpiece to a temperature of beta-annealing for a time in the range from 5 minutes to 24 hours. 10. The method according to p. 1, characterized in that before cooling the beta-annealed preform below the beta transition temperature of the titanium alloy, it further includes plastic deformation of the preform at the temperature of plastic deformation in the region of the beta phase of the titanium alloy. 11. The method according to p. 10, characterized in that the plastic deformation of the workpiece at a temperature of plastic deformation in the region of the beta phase of the titanium alloy includes at least one of the hood, forging by sediment and comprehensive forging of the workpiece. 12. The method according to p. 10, characterized in that the temperature of plastic deformation is in the range from the temperature of the beta transition of the titanium alloy to a temperature 300 ° F (167 ° C) above the temperature of the beta transition of the titanium alloy. 13. The method according to p. 10, characterized in that after plastic deformation of the workpiece, the workpiece is cooled to the forging temperature of the workpiece in the alpha + beta phase of the titanium alloy. 14. The method according to p. 10, characterized in that the plastic deformation of the preform includes forging the preform with a precipitate until the degree of deformation of the preform in the region of the beta phase in the range from 0.1 to 0.5 is reached. 15. The method according to p. 1, characterized in that it further includes, in the intervals between successive forging on the press, the ability to cool the adiabatically heated inner region of the workpiece to the temperature of the forging of the workpiece by heating the outer surface of the workpiece to the temperature of the workpiece forging. 16. The method according to p. 15, characterized in that it provides the possibility of cooling the adiabatically heated inner region of the workpiece during the cooling time of the inner region in the range from 5 seconds to 120 seconds. 17. The method according to p. 15, characterized in that the heating of the outer surface of the workpiece includes heating using one or more of the heating flame, heating in a chamber furnace, induction heating and heating by radiation. 18. The method according to p. 15, characterized in that it further includes heating the stamp of the forging machine used for forging the workpiece on the press, to a temperature in the range from the temperature of the forging of the workpiece to a temperature of 100 ° F (55.6 ° C) below the temperature of the forging blanks. 19. The method according to p. 1, characterized in that after reaching the total true strain of at least 1.0, the workpiece has an average grain size of alpha particles in the range of 4 μm or less. 20. The method according to p. 1, characterized in that the repetition of at least one of the forgings on the press until the total true deformation in the workpiece is at least 1.0 includes forging the workpiece on the press at a second temperature of the workpiece forging, the second temperature of the workpiece forging is within the alpha + beta phase region of the titanium alloy of the preform, and the second forging temperature of the preform is lower than the temperature of the forging of the preform. 21. A method of grinding grain size of a workpiece containing a titanium alloy, comprising: beta annealing of the workpiece; cooling the beta-annealed preform to a temperature below the beta transition temperature of the titanium alloy; and comprehensive forging of the workpiece, and comprehensive forging includes: forging a workpiece in a press at a temperature of forging a workpiece in the range of temperatures for forging a workpiece in the direction of the first orthogonal axis A of the workpiece to the desired final height with a strain rate sufficient to adiabatically heat the inner region of the workpiece, forging a workpiece in a press at a temperature of forging a workpiece in the direction of the second orthogonal axis B of the workpiece to a first height by means of blocking means, forging a workpiece in a press at a temperature of forging a workpiece in the direction of the third orthogonal axis C of the workpiece to a second height by means of blocking means, forging a workpiece in a press at a temperature of forging a workpiece in the direction of the second orthogonal axis B of the workpiece to the desired final height with a strain rate sufficient to adiabatically heat the inner region of the workpiece, forging a workpiece on a press at a temperature of forging a workpiece in the direction of the third orthogonal axis C of the workpiece to a first height by means of blocking means, forging a workpiece on a press at a temperature of forging a workpiece in the direction of the first orthogonal axis A of the workpiece to a second height by means of blocking means, forging a workpiece in a press at a temperature of forging a workpiece in the direction of the third orthogonal axis C of the workpiece to the desired final height with a strain rate sufficient to adiabatically heat the inner region of the workpiece, forging a workpiece on a press at a temperature of forging a workpiece in the direction of the first orthogonal axis A of the workpiece to a first height by means of blocking means, forging a workpiece on a press at a temperature of forging a workpiece in the direction of the second orthogonal axis B of the workpiece to a second height by means of blocking means and the repetition of at least one of the previous forging on the press until the total true deformation in the workpiece is at least 1.0, wherein the workpiece forging temperature is in the range from a temperature 100 ° F (55.6 ° C) below the beta transition temperature of the titanium alloy to 700 ° F (388.9 ° C) lower than the beta transition temperature of the titanium alloy, and the deformation rate used during forging on the press is in the range from 0.2 s ^-1 to 0.8 s ^-1 . 22. The method according to p. 21, characterized in that at least one of the forgings on the press is repeated until the total true deformation in the workpiece reaches from at least 1.0 to less than 3.5. 23. The method according to p. 21, characterized in that the preform contains one of an alpha + beta titanium alloy or metastable beta titanium alloy. 24. The method according to p. 23, wherein the titanium alloy contains at least one of the grain-stopping alloying additives or beta-stabilizing additives effective to reduce alpha phase release and alpha kinetics of growth. 25. The method according to p. 21, characterized in that the preform contains a titanium alloy selected from alloy Ti-6Al-2Sn-4Zr-6Mo (UNS R56260), alloy Ti-6Al-2Sn-4Zr-2Mo-0.08Si (UNS R54620), Ti-4Al-2.5V alloy (UNS R54250), Ti-6Al-7Nb alloy (UNS R56700) and Ti-6Al-6V-2Sn alloy (UNS R56620). 26. The method according to p. 21, characterized in that the cooling of the beta-annealed preform includes cooling the preform to ambient temperature. 27. The method according to p. 21, characterized in that the cooling of the beta-annealed preform includes cooling the preform to the forging temperature of the preform. 28. The method according to p. 21, characterized in that the beta annealing of the workpiece includes heating the workpiece to a temperature of beta annealing in the range from the beta transition temperature of the titanium alloy to a temperature 300 ° F (167 ° C) above the beta transition temperature of the alloy titanium. 29. The method according to p. 21, characterized in that the beta-annealing of the workpiece includes heating the workpiece to a temperature of beta-annealing for a time in the range from 5 minutes to 24 hours. 30. The method according to p. 21, characterized in that before cooling the beta-annealed preform to a temperature below the beta transition temperature of the titanium alloy, it further includes plastic deformation of the preform at a temperature of plastic deformation in the region of the beta phase of the titanium alloy. 31. The method according to p. 30, characterized in that the plastic deformation of the workpiece at a temperature of plastic deformation in the region of the beta phase of the titanium alloy includes one of hoods, forging by upset, or all-round forging of the workpiece. 32. The method according to p. 30, characterized in that the temperature of plastic deformation is in the range from the beta transition temperature of the titanium alloy to a temperature 300 ° F (167 ° C) above the beta transition temperature of the titanium alloy. 33. The method according to p. 30, characterized in that after plastic deformation of the workpiece, the workpiece is cooled to the forging temperature of the workpiece in the alpha + beta phase of the titanium alloy. 34. The method according to p. 30, characterized in that the plastic deformation of the preform involves forging the preform with a precipitate until the degree of deformation of the preform in the region of the beta phase in the range from 0.1 to 0.5 is reached. 35. The method according to p. 21, characterized in that it further includes, in the intervals between successive forgings of the workpiece on the press, allowing the adiabatically heated inner region of the workpiece to be cooled to the forging temperature of the workpiece by heating the outer surface region of the workpiece to the temperature of the workpiece forging. 36. The method according to p. 35, characterized in that it provides the ability to cool the adiabatically heated inner region of the workpiece for a time in the range from 5 seconds to 120 seconds. 37. The method according to p. 35, characterized in that the heating of the outer surface of the workpiece includes heating using one or more of the heating flame, heating in a chamber furnace, induction heating and heating by radiation. 38. The method according to p. 35, characterized in that it further includes heating the stamp of the forging machine used for forging the billet on the press to a temperature in the range from the temperature of the forging of the billet to a temperature 100 ° F (55.6 ° C) below the forging temperature blanks. 39. The method according to p. 21, characterized in that after achieving a total true strain of at least 1.0, the workpiece has an average alpha particle size of 4 microns or less. 40. The method according to p. 21, characterized in that the repetition of at least one of the forgings on the press until the total true deformation in the preform reaches at least 1.0 includes forging the preform on the press at a second temperature of the forging preform, the second forging temperature of the preform lies within the alpha + beta phase region of the titanium alloy in the workpiece, and the second workpiece forging temperature is lower than the workpiece forging temperature.

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