RU2688109C2 - Methods for processing titanium alloys - Google Patents

Abstract

FIELD: metallurgy.SUBSTANCE: invention relates to methods of processing titanium alloys. Proposed method comprises the steps of billet beta-annealing, billet cooling to temperature below beta-transition temperature of titanium alloy and comprehensive forging of billet. Inclusive forging includes forging of workpiece on press in direction of first axis of workpiece with rate of deformation sufficient for adiabatic heating of inner area of workpiece, forging the workpiece on press in the direction of the second axis of the workpiece at a rate of deformation sufficient for adiabatic heating of the inner area of the workpiece, forging the workpiece on press in the direction of the third axis of the workpiece with a rate of deformation sufficient for adiabatic heating of the inner area of the workpiece. First axis, the second axis and the third axis are not the same or parallel. At least one of workpiece forging is repeated on press to achieve total true deformation of work piece by at least 1.0. Billet forging temperature is in range from 100 °F (55.6 °C) below temperature of beta-transition of titanium alloy to temperature of 700 °F (388.9 °C) below temperature of beta-transition of titanium alloy. Deformation rate used during forging on press is in range from 0.2 to 0.8 s. Fine-grain equiaxial structure is obtained in billets.EFFECT: special forging equipment is not required.29 cl, 16 dwg, 1 tbl, 6 ex

Description

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

TECHNICAL FIELD

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

BACKGROUND

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

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

[0005] In the known commercial methods of forging titanium and titanium alloys, for forming coarse-grained or fine-grained microstructures, strain rates range from 0.03 s ^-1 to 0.10 s ^-1 using multiple reheating and forging steps.

[0006] In the known methods for manufacturing fine-grained, very fine-grained or ultrafine microstructures, a comprehensive forging (MAF) process is used with an ultra-slow strain rate of 0.001 s ^-1 or slower (as described, for example, in the Materials Science Forum ") (G. Salishchev et al.), Edition 584-586, p. 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 grinding grain in the process of comprehensive forging with ultra slow strain rates is the ability to work continuously in the mode of dynamic recrystallization, which is the result of the ultra slow strain rates used, i.e. 0.001 s ^-1 or slower. During dynamic recrystallization, the simultaneous formation of a kernel of grains, their growth and accumulation of dislocations occur. The generation of dislocations in freshly formed grains continuously reduces the driving force for grain growth, and the nucleation of grains is energetically favorable. In the process of comprehensive forging with ultra-slow strain rates, dynamic recrystallization is used to continuously recrystallize the grains during forging.

[0008] The relatively homogeneous cubes of the Ti-6-4 ultrafine alloy (UNS R56400) can be made using a comprehensive forging method with an ultra-slow strain rate, but the cumulative time spent on performing the comprehensive forging stages may be too large for commercial applications. In addition, the characteristics of a known large-size, commercially available forging equipment with open dies may not provide the ability to use the ultra slow strain rates required in such embodiments, and thus complete forging of commercial batches of products using ultra slow strain may be required specialized forging equipment.

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

DISCLOSURE OF INVENTION

[0010] According to a non-limiting aspect of the present invention (disclosure), a method of grinding a grain size of a billet containing a titanium alloy includes beta-annealing the billet. After beta annealing, the billet 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: perform the forging of the workpiece in a press at the temperature of the forging of the 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 for adiabatic heating of the inner region of the workpiece, forging the workpiece in the press at a temperature forging a workpiece located in the temperature range of the forging workpiece in the direction of the second orthogonal axis of the workpiece with a deformation rate sufficient for adia batic heating of the internal area of the workpiece, and forging the workpiece on a press at the temperature of the forging of the workpiece in the temperature range of the forging of the workpiece in the direction of the third orthogonal axis of the workpiece with a deformation rate sufficient for adiabatic heating of the internal area of the workpiece. Optionally, between successive forging stages in the press, the adiabatically heated inner region of the workpiece is cooled to or below the forging temperature of the workpiece in the forging temperature range of the workpiece and the outer surface of the workpiece is heated to the workpiece forging temperature or near it. At least one of the forging steps in the press is repeated until a total deformation of at least 1.0 is achieved in the workpiece. According to another non-limiting implementation variant, at least one of the forging steps in the press is repeated until a total strain in the range from 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 press forging 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 a grain size of a billet containing a titanium alloy includes a step of annealing the billet. After beta annealing, the billet 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] Carry out the forging of the workpiece on the press at the temperature of the forging of the workpiece in the temperature range of the forging of the workpiece in the direction of the first orthogonal axis A of the workpiece for blocked precipitation to the main deposited height with a deformation rate sufficient for adiabatic heating of the internal area of the workpiece. Used in this application, the main besieged height after precipitation is a distance equal to the desired final size after forging, for each orthogonal axis of the workpiece.

[0013] Carry out the forging of the workpiece on the press at the temperature of the forging of the workpiece in the temperature range of the forging of the workpiece in the direction of the second orthogonal axis B of the workpiece for blocked draft to the first besieged height. The first blocked draft is used to return the billet essentially to the shape of the billet prior to forging. Although the strain rate during the first blocked draft may be sufficient for adiabatic heating of the internal area of the workpiece, according to one non-limiting implementation variant, adiabatic heating during the first blocked draft may not be observed, since the total deformation created during the first blocked draft may be insufficient for significant adiabatic heating of the workpiece. The first deposited height of the blocked precipitation is greater than the main precipitated height of the precipitation.

[0014] Carry out the forging of the workpiece on the press at the temperature of the forging of the workpiece in the temperature range of the forging of the workpiece in the direction of the third orthogonal C axis of the workpiece for blocked precipitation to a second upset height. The second blocked sediment is applied to return the workpiece essentially to the shape of the workpiece before forging. Although the strain rate during the second blocked draft may be sufficient for adiabatic heating of the internal area of the workpiece, according to one non-limiting implementation, adiabatic heating during the second blocked draft may not be observed, since the total strain created during the second blocked draft may be insufficient for significant adiabatic heating of the workpiece. The second deposited height of the blocked precipitation is greater than the main precipitated height of the precipitation.

[0015] Carry out the forging of the workpiece on the press at the temperature of the forging of the workpiece in the temperature range of the forging of the workpiece in the direction of the second orthogonal axis B of the workpiece for blocked sediment to the main deposited height with a deformation rate sufficient for adiabatic heating of the internal area of the workpiece.

[0016] Carry out the forging of the workpiece on the press at the temperature of the forging of the workpiece in the temperature range of the forging of the workpiece in the direction of the third orthogonal C axis of the workpiece for blocked draft to the first besieged height. The first blocked draft is used to return the billet essentially to the shape of the billet prior to forging. Although the strain rate during the first blocked draft may be sufficient for adiabatic heating of the internal area of the workpiece, according to one non-limiting implementation variant, adiabatic heating during the first blocked draft may not be observed, since the total deformation created during the first blocked draft may be insufficient for significant adiabatic heating of the workpiece. The first deposited height of the blocked precipitation is greater than the main precipitated height of the precipitation.

[0017] Carry out the forging of the workpiece on the press at the temperature of the forging of the workpiece in the temperature range of the forging of the workpiece in the direction of the first orthogonal axis A of the workpiece for the second blocked draft to the second upset height. The second blocked draft is used to return the billet essentially to the shape of the billet prior to forging. Although the strain rate during the second blocked draft may be sufficient for adiabatic heating of the internal area of the workpiece, according to one non-limiting implementation, adiabatic heating during the second blocked draft may not be observed, since the total strain created during the second blocked draft may be insufficient for significant adiabatic heating of the workpiece. The second deposited height of the blocked precipitation is greater than the main precipitated height of the precipitation.

[0018] Carry out the forging of the workpiece on the press at the temperature of the forging of the workpiece in the temperature range of the forging of the workpiece in the direction of the third orthogonal axis C of the workpiece for blocked draft to the main deposited height with a deformation rate sufficient for adiabatic heating of the internal area of the workpiece.

[0019] Carry out the forging of the workpiece on the press at the temperature of the forging of the workpiece in the temperature range of the forging of the workpiece in the direction of the first orthogonal axis A of the workpiece for the first blocked draft to the first besieged height. The first blocked draft is used to return the billet essentially to the shape of the billet prior to forging. Although the strain rate during the first blocked draft may be sufficient for adiabatic heating of the internal area of the workpiece, according to one non-limiting implementation variant, adiabatic heating during the first blocked draft may not be observed, since the total deformation created during the first blocked draft may be insufficient for significant adiabatic heating of the workpiece. The first deposited height of the blocked precipitation is greater than the main precipitated height of the precipitation.

[0020] Carry out the forging of the workpiece on the press at the temperature of the forging of the workpiece in the temperature range of the forging of the workpiece in the direction of the second orthogonal axis B of the workpiece for the second blocked draft to the second upset height. The second blocked draft is used to return the billet essentially to the shape of the billet prior to forging. Although the strain rate during the second blocked draft may be sufficient for adiabatic heating of the internal area of the workpiece, according to one non-limiting implementation, adiabatic heating during the second blocked draft may not be observed, since the total strain created during the second blocked draft may be insufficient for significant adiabatic heating of the workpiece. The second deposited height of the blocked precipitation is greater than the main precipitated height of the precipitation.

[0021] Optionally, between successive forging steps in a press according to a previous embodiment of the method, the adiabatically heated inner region of the workpiece is cooled to approximately the forging temperature of the workpiece in the forging temperature range of the workpiece and heated to the forging temperature of the workpiece in the forging temperature range of the workpiece. At least one of the forging steps in the press is repeated according to one embodiment, until a total strain 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 in the press is repeated until a total strain in the range from 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 press forging is in the range of 0.2 s ⁻¹ to 0.8 s ⁻¹ .

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The 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 Ti-6-4, Ti-6-2-4-6 and Ti-6-2-4-2 alloys, depending on temperature;

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

[0025] FIG. 3 schematically shows aspects of a non-limiting embodiment of a method of comprehensive forging with a high strain rate using temperature control for machining titanium alloys to grind grain sizes, with FIG. 2 (a), 2 (c) and 2 (e), non-limiting embodiments of the forging stages in a press are presented, and FIG. 2 (b), 2 (d) and 2 (f) represent optional non-limiting cooling and heating steps according to non-limiting aspects of the present invention;

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

[0027] FIG. 5 shows a flowchart that lists the steps of a method according to one non-limiting embodiment of processing titanium alloys according to the present invention, including slumping to a basic precipitated height along orthogonal axes to achieve the final desired workpiece size, as well as the first and second blocked draft

[0028] FIG. 6 shows a temperature-time graph of thermomechanical processing for a non-limiting embodiment of the method of comprehensive forging with a high strain rate 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 forging method with a high deformation rate for a comprehensive process according to the present invention;

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

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

[0032] FIG. 10 is a flowchart that lists the steps of a non-limiting embodiment of a process for treating by multiple precipitations and extraction of titanium alloys for grinding the grain size of the present invention;

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

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

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

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

[0037] FIG. 13 shows a micrograph of the microstructure of the alloy Ti-6-2-4-6, processed by the method of thermo-controlled all-round forging with a high strain rate according to the embodiment described in Example 3 of the present invention;

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

[0039] FIG. 15 shows a micrograph of the microstructure of the alloy Ti-6-2-4-2, processed by the method of heat-controlled all-round forging with a high strain rate according to the embodiment described in Example 5 of the present invention, according to which to minimize the buckling of the workpiece that occurs after each major draft, blocked draft;

[0040] FIG. 16 (a) shows a micrograph of the microstructure of the central region of a Ti-6-2-4-2 alloy processed by a method of heat-controlled all-round forging with a high strain rate according to one embodiment using a beta transition intersection as 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 processed by a method of heat-controlled all-round forging with a high strain rate according to one embodiment using a beta transition intersection as 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, non-limiting implementation options, unlike working examples or situations that indicate otherwise, all numbers expressing quantities or characteristics should be understood as being changed in all cases by the term "about." Accordingly, unless otherwise indicated, any numerical parameters set forth in the following description are approximations that can be changed depending on the desired properties that need to 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 amount of protection defined in the clauses of the attached formula, each numerical parameter should be considered at least in the 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 the subranges assigned to its category. For example, the range "1-10" is intended to contain all subranges between (and including) specified minimum value 1 and specified maximum value 10, i.e., having a minimum value that is equal to or greater than 1 and a maximum value that equal to or less than 10. Any maximum numerical limit specified in this application contains all the lower numerical limits included in its category, and any minimum numerical limit specified in this application contains all the higher numerical limits. Nichki included in its category. Accordingly, Applicants reserve the right to amend the present invention, including the claims, to explicitly indicate any sub-band included in the category of ranges explicitly stated in this application. All such ranges are intended for immanent disclosure in this application such that the correction to explicitly designate any such subranges meets the requirements of Law 35 of the US Code, 112, Article One, and Law 35 of the US Code, 132 (a).

[0045] The grammatical terms "one" and "some", if used in the present description, are intended to be interpreted in the inclusive sense: "at least one" or "one or more", unless otherwise specified. Thus, these terms are used in this specification to refer to at least one, not just 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 a greater number than one element can be considered and can be used or implemented in the described embodiments.

[0046] The present invention contains descriptions of various embodiments. It should be understood that all implementation options described in this application are illustrative and non-limiting examples. 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 appended 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 fully incorporated into the present application by reference, unless otherwise indicated, but only to the extent that the included material does not conflict with existing definitions, statements or other disclosure. explicitly stated in this application. Also, to the extent necessary, the expressive disclosure set forth in this application replaces any conflicting material incorporated by reference into this application. Any material or part thereof that is listed as incorporated by reference in the present application, but which conflicts with the existing definitions, statements, or other disclosure material formulated in this application, is included in the present application to the extent that no conflict occurs between it. included material and existing disclosure material.

[0048] One aspect of the present invention is directed to non-limiting embodiments of the method of comprehensive forging titanium alloys, which includes the use of high strain rates during the forging steps to reduce grain size. These embodiments of the method are generally indicated in the present invention as “comprehensive forging with a high strain rate” or “MAF with a high strain rate”. Used in this application, the terms "sludge" and "punch" interchangeably refer to an individual forging step on a press, at which the workpiece is forged between the surfaces of the stamp. Used in this application, the phrase "precipitated height" refers to the size or thickness of the workpiece, measured along one orthogonal axis after precipitation along this axis. For example, after precipitation by forging on a press along a specific axis to an upset height of 4.0 inches (101.6 mm), the thickness of the workpiece after forging on a press, measured along this axis, is approximately 4.0 inches (101.6 mm ). The concept and use of besieged 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 making blanks with ultrafine grains from alloys such as Ti-6Al-4V (ASTM Grade 5; UNS R56400), which can also be labeled as "Ti-6-4", All-round forging with a high strain rate will be used, at which the workpiece is forged at least to a total strain of 3.5. This process is described in U.S. Patent Application No. 12 / 882,538, filed Sept. 15, 2010, entitled "Technological Schemes for Titanium and Titanium Alloys" (hereinafter referred to as '538 Application'), which is fully incorporated into the present application by reference. Achieving a strain of at least 3.5 may require considerable processing time and is associated with increased complexity, which increases the cost of production and increases the likelihood of unforeseen problems. The present invention proposes a comprehensive forging process with a high strain rate, which can provide structures with ultrafine grit using a total strain in the range of at least 1.0 to less than 3.5.

[0050] The methods according to 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 effective alpha phase release and growth kinetics than the alloy Ti-6-4. In particular, the alloy Ti-6Al-2Sn-4Zr-2Mo-0.08Si (UNS R54620), which can also be specified as the alloy "Ti-6-2-4-2", has a slower effective alpha kinetics than an alloy of Ti-6-4, as a result of the presence of additional locking grain elements (stopping migration of dislocations at the grain boundaries of elements), such as Si. In addition, the Ti-6Al-2Sn-4Zr-6Mo alloy (UNS R56260), which can also be referred to as the "Ti-6-2-4-6" alloy, has a slower effective alpha kinetics than the T-6 alloy -4, as a result of increased beta-phase 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 alloying additives. 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 slows down the diffusion of atoms in the alloy at the processing temperature of this alloy. The result of relatively slow effective alpha release and kinetics of growth for Ti-6-2-4-2 and Ti-6-2-4-6 alloys is that beta heat treatment, which is used before comprehensive forging according to implementation options of the present of the invention leads to the formation of a small and stable size of alpha packets compared to the effect of such processing of the Ti-6-4 alloy. In addition, after beta-heat treatment and cooling, alloys Ti-6-2-4-2 and Ti-6-2-4-6 have a fine-grained beta-structure, which limits the growth kinetics of the alpha grain.

[0051] The effective alpha growth kinetics can be evaluated by identifying the most slowly diffusing particles at a temperature immediately below the beta transition. This approach is theoretically substantiated and experimentally tested 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 capacity of all potential alloy components are not always available; however, literature reviews, such as in Titan (Second Edition, 2007) (Lutjering and Williams), generally agree with the following relative classification of some common alloy components:

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 with relatively low strain than for Ti-6-4 alloy, in which aluminum diffusion controls the kinetics. Based on the relationships 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 the inclusion of slowly diffusing elements to reduce the effective alpha-phase kinetics, a decrease in the beta transition temperature in the alloys that are controlled by the diffusion of aluminum creates the same effect. Lowering the beta transition temperature to 100 ° C reduces the diffusion capacity of aluminum in the beta phase by about an order of magnitude at the beta transition temperature. Alpha kinetics in alloys such as ATI 425 ^® (Ti-4Al-2.5V; UNS 54250) and Ti-6-6-2 (Ti-6Al-6V-2SN; UNS 56620) is 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), which is usually the biomedical version of the Ti-6Al-4V alloy, can also exhibit delayed effective alpha kinetics due to its niobium content.

[0054] Initially, it was expected that alpha-beta alloys, with the exception of the Ti-6-4 alloy, could be processed under conditions similar to those described in the '538 Application at temperatures that would lead to similar volume fractions of the alpha phase. For example, according to preliminary estimates made using the PANDAT program, which is an affordable computing tool available from Computherm, LLC, Madison, Wisconsin, USA, it was predicted that Ti-6-4 alloy at 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, Ti-6-2-4-2 and Ti-6-2-4-6 alloys crack when processed in the manner in which Ti-6-4 alloy was treated in Application '538 using the temperature for which the formation was predicted similar volume fractional concentration of 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 fractional concentrations of the alpha phase and / or significantly reduced deformation per pass.

[0055] Each of the changes in a comprehensive forging process with a high strain rate, including temperature or temperatures of alpha / beta forging, strain rate, strain on impact, pause time between blows, the number and duration of repeated heating and intermediate heat treatments, can affect the resulting microstructure, as well as the presence and degree of cracking. Initially, reduced total deformations were undertaken to block cracking with no hope of achieving ultra-fine granular structures. However, after research, samples processed using reduced total deformations showed a distinct prospect of creating ultra-fine granular structures. This result was completely unexpected.

[0056] According to some non-limiting embodiments of the present invention, the method of manufacturing ultra-small-sized grains includes the steps according to which: 1) a titanium alloy is chosen that contains an efficient alpha-phase growth kinetics that is slower than that of Ti-6-4; 2) The titanium alloy beta annealing to create a sustained alpha package of small size, and 3) perform a comprehensive forging with a high strain rate (or a similar derivative process, such as the multiple draft and drawing (MUD) process, described in Bid '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 "fine" used in this application to describe the grain and package size refers to the smallest grain size and package that can be achieved and which according to non-limiting implementation options is on the order of 1 micron. The word "sustainable" is used in this application to indicate that the stages of comprehensive forging do not substantially increase the size of the alpha grain and do not increase the size of the alpha grain by more than about 100%.

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

[0058] After the beta annealing step (18), the blank 24 is cooled in step (20) to a temperature below the beta transition temperature for the titanium alloy in the blank 24. According to one non-limiting embodiment of the present invention, the blank is cooled to ambient temperature. The term "ambient temperature" as used herein refers to an 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 implementation variant, the cooling (20) may include a hardening step. Hardening involves the steps of immersing the billet 24 in water, oil, or another suitable liquid, and is a process known to a person skilled in the field of metallurgy. According to other non-limiting implementation options, in particular, for blanks that have a small size, cooling (20) may include air cooling. Any method of cooling the billet 24 of titanium alloy, which is known to the expert at the present time or which will be known later, 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 located in the temperature range suitable for the forging of the workpiece for subsequent all-round forging with a high strain rate.

[0059] After cooling (20), the workpiece in step (26) is subjected to comprehensive forging with a high strain rate. It will be understood by those skilled in the art that all-round forging (“MAF”), which may also be referred to as “A-B-C” forging, is a form of rigid plastic deformation. Comprehensive forging with a high strain rate in step (26) according to one non-limiting embodiment of the present invention involves the steps of heating (in step 22, in FIG. 2) a billet 24 containing a titanium alloy to a batch forging temperature in the batch forging temperature range which is within the alpha + beta phase region of the titanium alloy, after which a comprehensive forging is performed in step (26) using a high strain 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 strain rate is used in 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 comprehensive forging cycle "ABC" with a high strain rate per cycle, the temperature of the inner region of the titanium alloy billet 24 should not exceed the temperature (T _β ) of the beta transition of the titanium alloy in the billet. Thus, according to such non-limiting implementation options, the forging temperature of the workpiece at least for the final ABC forging cycle or at least for the last stroke of a comprehensive forging cycle with a high strain rate must be chosen so that during comprehensive forging with a high deformation rate, the internal temperature the area of the workpiece was not equal to or did not exceed the temperature of the beta transition of the alloy. For example, according to one non-limiting embodiment of the present invention, the temperature of the inner region of the workpiece 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 a final cycle of ABC strikes with a high strain rate during the all-round forging process or during at least the last forging strike of a press, at which the total strain at least in the workpiece area is at least equal to 1, 0 or is in Range of at least 1.0 to less than 3.5.

[0061] In a non-limiting embodiment of implementing a comprehensive forging with a high strain rate according to the present invention, the forging temperature of the workpiece includes a temperature that is within the range of the forging temperature of the workpiece. In a non-limiting embodiment, the forging temperature range of the workpiece 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 temperature of the beta transition titanium alloy. According to another non-limiting embodiment, the forging temperature range of the workpiece is 300 ° F (166.7 ° C) below the beta transition temperature of the titanium alloy and 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 the forging stroke does not occur.

[0062] According to one non-limiting embodiment shown in FIG. 2, applied to the Ti-6-2-4-2 alloy, which has a beta transition temperature (T _β ) of approximately 1820 ° F (996 ° C), the forging temperature range of the workpiece can 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 the Ti-6-2-4-6 alloy, which has a beta transition temperature (T _β ) of approximately 1720 ° F (940 ° C), the forging temperature range of the workpiece can be from 1020 ° F (548.9 ° C) up to 1620 ° F (882.2 ° C) or in accordance with another embodiment from 1095 ° F (590.6 ° C) to 1420 ° F (771.1 ° C). According to another non-limiting embodiment shown in FIG. 2 applied to the ATI 425 ^® alloy (UNS R54250), which may also be referred to as “Ti-4Al-2.5V” alloy and which has a temperature (T _β ) beta transition 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 the one shown in FIG. 2 embodiment of the present invention alloy Ti-6Al-6V-2Sn (UNS 56620), which can also be referred to as the alloy "Ti-6-6-2" and which has a temperature (T _β ) beta transition 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 implementation variant from 1115 ° F (601.7 ° C ) to 1435 ° F (779.4 ° C). The present invention encompasses the use of comprehensive forging with a high strain rate and its derivatives, such as the MUD method described in the '538 Application, to titanium alloys, which are distinguished by slow effective alpha release and growth kinetics, unlike Ti-6-4.

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

[0064] High strain 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 strain 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 a high strain rate, as indicated above, the inside of the titanium alloy billet may be adiabatically heated to a temperature of about 200 ° F (111.1 ° C) above the forging temperature of the workpiece. According to another non-limiting embodiment, the inner region is adiabatically heated to a temperature in the range from about 100 ° F (55.6 ° C) to about 300 ° F (166.7 ° C) above the forging temperature during the forging operation on the press. According to yet another non-limiting embodiment, during press-forging, the inside region is adiabatically heated to a temperature in the range of from about 150 ° F (83.3 ° C) to about 250 ° F (138.9 ° C) above the forging temperature of the workpiece. . As stated above, according to non-limiting implementation options, no part of the preform should be heated above the beta transition temperature of the titanium alloy during the last stroke cycle with A-B-C comprehensive forging with a high strain 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 sediment in height or other size that is in the range from 20% to 50%, i.e., this size is reduced by percentage value within the specified range. According to another non-limiting embodiment, during the forging on the press in step (28), the workpiece 24 is plastically deformed to sediment in height or other size in the range from 30% to 40%.

[0067] FIG. 4 schematically shows a known all-round forging process with an ultra-slow strain rate (0.001 s ^-1 or less). In general, the aspect of all-round forging is that after each three-way, (i.e., "three-stroke") cycle by means of a forging device (which may be, for example, an open die forging press), the workpiece takes the form and size had just before the first strike of this cycle of three hits. For example, after the first forging strike on a cube-shaped workpiece with an edge of 5 inches (127 mm) in the direction of the axis a, turning 90 ° and a second impact in the direction of the orthogonal axis b, followed by a rotation of 90 ° and the third forging by striking in the direction of the orthogonal axis "c", said blank will return to the original cube shape with an edge of approximately 5 inches (127 mm). In other words, despite the fact that the cycle of three blows deforms the cube in three stages along the three orthogonal axes of the cube, as a result of the permutation of the specified workpiece between the individual blows and the choice of draft at each blow, the total result of the three forging deformations consists in returning 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 herein as “first strike,” may include forging a workpiece on a press with a downward impact on the upper part to settle the workpiece to a predetermined upset height while the workpiece is at a temperature in the forging temperature range. As used in this application, the term “settled height” refers to the size of the workpiece after the completion of a particular stage of precipitation during press forging. For example, to achieve an upset height of 5 inches (127 mm), the workpiece is forged to a size of approximately 5 inches (127 mm). In a particular non-limiting embodiment of the method according to the present invention, the settled height is, for example, 5 inches (127 mm). According to another non-limiting embodiment, the seated height is 3.25 inches (82.55 mm). Other besieged 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) are within the protection scope of the implementation options described in this application, but should not be construed as limiting the protection scope of the present invention. The graded heights are limited only by the characteristics of the forging machine and, optionally, as will be seen from the present application, the characteristics of the thermal management system according to non-limiting embodiments of the present invention designed to maintain the workpiece at the forging temperature. Precipitated heights of less than 3 inches (76.2 mm) also fall within the protection scope of the implementation options described in this application, and such relatively small upset heights are limited only by the required characteristics of the finished product. Using upset heights of about 30 inches (762 mm), for example, in the methods of the present invention, it is possible to manufacture billet blanks (for example, with a side of 30 inches (762 mm)) in the form of a cube of titanium alloy having a small grain size, a very small size grain or ultra-fine grain size. Known alloys billetised in cubic form are used as blanks forged by discs, rings and body parts, for example, for aircraft turbines or ground-based turbines.

[0069] The specified besieged heights to be used in various non-limiting embodiments of the methods of the present invention can be determined by a person skilled in the art without undue experimentation when considering the present invention. Specified elevated heights can be determined by a specialist without undue experimentation. Specified besieged heights depend on the susceptibility of a given alloy to cracking during forging. For alloys that have a higher susceptibility to cracking, increased precipitated heights are required, i.e., reduced strain on impact to prevent cracking. When choosing an upset height, the adiabatic heating threshold should also be considered, since at least in the last stroke cycle the temperature of the workpiece should not exceed the temperature (T _β ) of the alloy's beta transition. In addition, when selecting an upset height, the ultimate characteristics of the forging press must also be taken into account. For example, during extrusion of a cubic billet with a 4-inch rib (101.6 mm) its cross-sectional area increases during the extrusion stage. Also increases the total load that is required to deform the workpiece with the required rate of deformation. The specified total load cannot exceed the characteristics of the forging press. In addition, the choice of besieged heights must take into account the geometry of the workpiece. Increased deformations can lead to bulging of the workpiece. Too much sediment can lead to a significant flattening of the workpiece in such a way that the next forging blow in the direction of another orthogonal axis can cause the workpiece to bend.

[0070] According to some non-limiting embodiments, the precipitated heights used at each stroke along the orthogonal axis are equivalent. According to some other non-limiting embodiments, the upset heights used at each stroke along the orthogonal axes are not equivalent. The following describes non-limiting embodiments of a comprehensive forging with a high strain rate using nonequivalent besieged heights for each orthogonal axis.

[0071] After the step (28) of forging 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 comprises a step (step 32) according to which the adiabatically heated inner region (not shown) of the workpiece is cooled to a temperature that is equal to or close to the forging temperature in the range Forging temperature of the workpiece, as shown in FIG. 3 (b). According to various non-limiting implementation options, the cooling times of the inner region or the “standby” times may 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. According to various non-limiting implementation options, the term "adiabatically heated inner region" of the preform as used in this application refers to an area 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 workpiece. It will be obvious to a person skilled in the art that the time required to cool the inner area of the workpiece to a temperature equal to or close to the forging temperature of the workpiece will depend on the size, shape and composition of the workpiece 24, as well as on the atmosphere conditions surrounding the workpiece 24.

[0072] During the cooling period of the inner region, an aspect of the heating control system 33 according to some non-limiting implementation options described in this application does not necessarily include heating (at step 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 uniform or close to uniform and essentially isothermal conditions at the forging temperature or close to it, the temperature before each blow in the process of comprehensive forging with a high deformation rate. The optional heating (at step 34) of the outer surface area 36 of the workpiece 24 after each impact along axis A, after each impact along axis B and / or after each impact along axis C should be considered to fall within the protection scope of the present invention. According to various non-limiting embodiments the outer surface of the workpiece is optionally heated (at step 34) after each ABC stroke cycle. According to other non-limiting embodiments, the outer surface area is not necessarily heated after any impact or cycle of impacts, while the overall temperature of the workpiece during the forging process is maintained within the temperature range of the forging of the workpiece. The periods of time during which the workpiece must be heated to maintain the temperature of the workpiece 24 in uniform or close to uniform and substantially isothermal conditions at a temperature equal to or close to the temperature of the forging of the workpiece, before each blow in the process of comprehensive forging with a high strain rate may 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 blank used in the present application refers to an area extending inwardly from the outer surface of the blank 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 implementation options, the heating (at step 34) of the outer surface area 36 of the workpiece 24 can be implemented 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 a press, the whole billet can be placed in a kiln or otherwise heated to a temperature in the forging temperature range.

[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 be cooled 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 other certain non-limiting embodiments of the present invention, as an optional feature, between each of the forging impacts A, B and C, the heating control system 33 is used to heat the outer surface region 36 of the workpiece and allow the adiabatically heated interior region to be cooled during the cooling time of the inner region such that the temperature of the workpiece returns to essentially a uniform temperature within the temperature range of the forging preparation. Non-limiting embodiments of the method according to the present invention, which used: (1) a heating control system 33 for heating the outer surface area of the workpiece to a temperature within the forging temperature range, and (2) a period during which the adiabatically heated inner region is cooled to temperatures within the temperature range of the forging of the workpiece may be referred to in this application as "thermo-controlled all-round forging with a high strain rate". The surface-heating mechanisms 38 contain, among other things: flame heaters configured to be heated with a flame; induction heaters, made with the possibility of induction heating; and radiant heaters configured to be heated by radiation from the outer surface of the blank 24. Other mechanisms and methods for heating the outer surface area of the blank will be apparent to those skilled in the art after considering the present invention, and all such mechanisms and methods should be considered to fall within the protection scope of the present invention. A non-limiting embodiment of the heating mechanism 38 for heating the outer surface region may include a chamber furnace (not shown). The chamber oven can be configured to use various heating mechanisms to heat the outer surface area of the workpiece using one or more of the flame heating mechanisms, radiant heating mechanisms, induction heating mechanisms, and any other suitable heating mechanism known to those skilled in the art or that 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 forging temperature of the workpiece that is within the temperature range of the forging workpiece using one or more preheaters 40 molds of the heating control system 33. Mold preheaters 40 may be used to maintain the temperature of the dies 42 or the surfaces of the 44 forging dies on a press equal to or close to the forging temperature that is within the temperature range of the forging of the workpiece. According to one non-limiting implementation variant, the dies 42 in the heating control system are heated to a temperature within the range from the forging temperature of the workpiece to a temperature 100 ° F (55.6 ° C) below the forging temperature of the workpiece. Mold heaters 40 may heat dies 42 or the surface of a 44 forging dies using any suitable heating mechanism currently known or later known to, including, but not limited to, flame heating mechanisms, radiant heating mechanisms, contact heating mechanisms and / or induction heating mechanisms. According to one non-limiting implementation variant, the mold preheater 40 may be a component of a chamber furnace (not shown). Although the heating control system 33 is shown in place and is 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 at the site during press 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 comprehensive forging method (26) according to the present invention comprises forging (in step 46) of the workpiece 24 on a press at the forging temperature of the workpiece in the temperature range of the forging of the workpiece in the direction (B) of the second orthogonal axis 48 the workpiece 24 using the strain rate, which is sufficient for adiabatic heating of the workpiece 24 or at least the inner region of the workpiece 24 and plastic deformation of the workpiece 24. According to one non-limiting variant 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 the forging on the press (at step 46), the workpiece 24 is plastically deformed for plastic deformation in the range from 30% to 40% of upsetting height or other size. According to one non-limiting implementation variant, the blank 24 may be subjected to forging on a press (in step 46) in the direction of the second orthogonal axis 48 to the same settled height used in the first stage (28) of forging on a press. According to another non-limiting implementation variant, the blank 24 may be subjected to forging on the press in the direction of the second orthogonal axis 48 to an upset height that differs from that used in the first stage (28) of forging on the press. According to another non-limiting embodiment, the inner region (not shown) of the blank 24 is adiabatically heated during the forging step (46) on the press to the same temperature as in the first forging step (28) on the press. According to other non-limiting embodiments, the high strain rates used for press forging (in step 46) are in the same ranges of strain rates described for the first press forging step (28).

[0077] According to one non-limiting embodiment shown in FIG. 2 (b) and 2 (d), the workpiece 24 may rotate (in the direction of arrow 50) between subsequent forging steps on the press (for example, steps (28), (46), (56)) to represent different orthogonal axes on the forging surface. Such a rotation can be referred to as the rotation "A-B-C". It is understood that when using different configurations of the forging machine, the plunger of the press 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 or the forging machine is not required. Obviously, an important aspect is the relative change in the position of the workpiece and the plunger used, and thus rotation (in the direction of 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 relative to different orthogonal axes between forging stages on a press is mandatory for completing the comprehensive forging process (26).

[0078] According to non-limiting implementation options in which rotation A-B-C is required (in arrow 50), the workpiece 24 can be manually rotated by the forging machine operator or an automatic rotation system (not shown) providing rotation A-B-C (in arrow 50). The automatic rotation system A-B-C may include, among other things, a self-balancing handling tool kit with clamps or similar tools to provide a non-limiting thermo-controlled version of the implementation of comprehensive forging with a high strain rate 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), the method (20) optionally includes the steps according to which, at step 52, it is possible to cool the adiabatically heated inner region (not shown) of the workpiece to a temperature equal to or close to the forging temperature of the workpiece, as shown in FIG. 3 (d). According to some non-limiting implementation options, the cooling times of the inner region or the waiting times may be in the range, 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 times depend 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 period of time for optional cooling of the inner region, an optional aspect of the heating control system 33 according to some non-limiting implementation options described in this application includes the steps of heating (at step 54) the outer surface region 36 of the workpiece 24 to 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 in uniform or close to homogeneous and essentially isothermal conditions at the forging temperature of the workpiece or close to it before each blow in the process of comprehensive forging with a high strain rate. According to various non-limiting implementation options 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 temperature of the workpiece is returned to a substantially uniform temperature equal to or close to the forging temperature of the workpiece. , between each forging stroke 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 time of the inner region, the temperature of the workpiece returns to a substantially uniform temperature within the temperature range forging the workpiece, before each stroke all-round forging with a high strain rate.

[0081] According to one non-limiting embodiment, the heating (at step 54) of the outer surface region 36 of the blank 24 can be performed 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 be heated with a flame; induction heaters, made with the possibility of induction heating; and radiant heaters configured to be heated by 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 area 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 considered to fall within the protection scope of the present invention. The chamber oven can be configured to use different heating mechanisms to heat the outer surface of the workpiece, and such heating mechanisms can include one or more of the 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 later.

[0082] According to another non-limiting embodiment, the outer surface region 36 of the blank 24 is further heated (at step 54) and maintained at a temperature equal to or close to the forging temperature of the blank that is within the range of the forging temperature of the blank using one or more heaters 40 molds of the heating control system 33. Mold preheaters 40 may be used to maintain the temperature of the dies 42 or the surfaces of the 44 forging dies on a press equal to or close to the forging temperature that is within the temperature range of the forging of the workpiece. Mold heaters 40 may heat dies 42 or the surface of a 44 forging dies using any suitable heating mechanism currently known or later known to, including, but not limited to, flame heating mechanisms, radiant heating mechanisms, contact heating mechanisms and / or induction heating mechanisms. According to one non-limiting implementation variant, the mold preheater 40 may be a component of a chamber furnace (not shown). Although the heating control system 33 is shown in place and is used during steps (32), (52), (60) of balancing and cooling in the process (26) of comprehensive forging 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 at the site during press 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 24 is forged on a press at a forging temperature in the forging temperature range of the workpiece in the direction (C) of the third orthogonal axis 58 billet 24 using plunger speed and strain rate, which are sufficient for adiabatic heating of billet 24 or at least adiabatic heating of the inner region of the billet and plastic deformation of the billet 24. С 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 the forging on the press (at step 56), the workpiece is plastically deformed for plastic deformation in the range from 30% to 40% sediment height or other size. According to one non-limiting implementation variant, the blank 24 can be machined by press forging (at step 56) in the direction of the third orthogonal axis 58 to the same settled height used in the first press forging stage (28) and / or second stage (46) forging on the press. According to another non-limiting implementation variant, the blank 24 can be processed 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 forging step on the press. According to another non-limiting embodiment of the present invention, the inner region (not shown) of the blank 24 is adiabatically heated during press forging step (56) to the same temperature as in the first press forging step (28). According to other non-limiting implementation options, the high strain rates used for press forging (in step 56) are in the same ranges of strain rates that are described for the first press forging step (28).

[0084] According to one non-limiting embodiment, as indicated by arrow 50 in FIG. 3 (b), 3 (d) and 3 (e), the blank 24 can rotate (as indicated by arrow 50) to the desired orientation of a different orthogonal axis between subsequent forging steps in a press (for example, at steps 46, 56). As described above, such a rotation may be denoted as rotation A-B-C. It is understood that when using different designs of the forging machine, it may be possible to rotate the plunger on the forging machine, instead of rotating the workpiece 24, or the forging machine may be equipped with multi-axis plungers such that rotation of the workpiece and the forging machine is not required. Thus, rotation in the direction of the arrow 50 of the blank 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 relative to different orthogonal axes between forging stages on a press is mandatory for completing the comprehensive forging process (26).

[0085] After the 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 the steps of allowing the adiabatically heated inner region (not shown) of the workpiece to be cooled (at step 60) to a temperature equal to or close to the forging temperature of the workpiece, as shown in FIG. 3 (f). The cooling time 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 period, an optional aspect of the heating control system 33 according to the non-limiting implementation options described in this application includes the step of heating (at step 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 in uniform or close to uniform and substantially isothermal temperature conditions at a temperature equal to or close to the forging temperature of the workpiece before each stroke of the comprehensive forging process with a high strain rate. According to non-limiting implementation options by using the heating control system 33 to heat the outer surface region 36, while allowing the adiabatically heated inner region to cool, during the predetermined cooling time of the inner region, the temperature of the workpiece returns to a substantially uniform temperature equal to or close to the forging temperature of between each forging stroke ABC. According to another non-limiting implementation of the present invention by using the heating control system 33 to heat the outer surface region 36, while allowing the adiabatically heated inner region to cool for the predetermined cooling time of the inner region, the temperature of the workpiece is returned to substantially isothermal conditions within the forging temperature range of the workpiece between successive forging strokes abc.

[0087] According to one non-limiting embodiment, the heating (in step 62) of the outer surface region 36 of the blank 24 may be implemented 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 be heated with a flame; induction heaters, made with the possibility of induction heating; and / or radiant heaters configured to be heated by radiation from the blank 24. Other mechanisms and methods for heating the outer surface area of the blank will be apparent to those skilled in the art after considering 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 the surface heating mechanism 38 may include a chamber furnace (not shown). The chamber oven can be configured to use different heating mechanisms to heat the outer surface of the workpiece, and such heating mechanisms can include one or more of the 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 later.

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

[0089] An aspect of the present invention includes a non-limiting embodiment in which one or more press forging steps along the three orthogonal axes of the workpiece are repeated until a total strain of at least 1.0 is achieved in the workpiece. The total strain is the total true strain. The term "true deformation" is also known to specialists as "logarithmic deformation" or "effective deformation." As shown in FIG. 2, in step (g) (step 64), one or more steps (28), (46), (56) of forging on the press are repeated until a total strain of at least 1.0 or in the range from at least 1.0 to less than 3.5. In addition, it is believed that after reaching the required deformation at any of the steps (28), (46) or (56) forging on the press, additional forging on the press is unnecessary, and optional balancing steps (i.e., steps (32), (52) or (60), which provide the possibility of cooling the internal area of the workpiece to a temperature equal to the forging temperature of the workpiece or close to it, and steps (34), (54) or (62), which heat the outer surface of the workpiece to temperature equal to the temperature of the forging billet or close to it temperature) e are necessary, and the workpiece can be simply cooled to ambient temperature, or, according to one non-limiting embodiment, cooled in a quenching fluid, or according to another non-limiting embodiment, the cooled air or any rapid cooling method.

[0090] it Should be understood that according to one non-limiting implementation variant, the total strain is the total strain in the entire workpiece after all-round forging, as described in this application. According to non-limiting embodiments of the present invention, the total strain may include equal deformations along each orthogonal axis, or the total strain may include different deformations on one or more orthogonal axes.

[0091] According to one non-limiting embodiment of the implementation after beta annealing, the workpiece can be subjected to comprehensive forging at two different temperatures in the alpha-beta phase. For example, as shown in FIG. 3, repeating the step (64) shown in FIG. 2 may include repeating one or more steps (a) - (optional b), (c) - (optional d), and (e) - (optional f) at the first temperature in the alpha-beta phase until some deformation, followed by repeating one or more steps (a) - (optional b), (c) - (optional d) and (e) - (optional f) at the second temperature in the alpha-beta phase until after completion of the final stage (a), (b) or (c) forging on the press (i.e., stage (28), (46), (56)) in the workpiece will not be achieved total strain at least re 1.0 or deformation in the range of at least 1.0 to less than 3.5. According to one non-limiting embodiment, the second temperature in the alpha-beta phase is lower than the first temperature in the alpha-beta phase. 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 temperatures of all-round forging in a press should be considered as falling into protection scope of the present invention as long as the temperatures are within the forging temperature range. It should also be considered that according to one non-limiting embodiment, the second temperature in the alpha-beta phase is higher than the first temperature in the alpha-beta phase.

[0092] According to another non-limiting embodiment of the present invention, in order to ensure uniform deformation in all directions during pressing along axis A, pressing along axis B and pressing along axis C, different deposits are used. The use of all-round 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 alpha grain in the workpiece. For example, non-uniform deformation can be introduced into a cubic billet by forging a cube with a 4-inch edge (101.6 mm) with a high deformation rate, first along axis A to a height of 3.0 inches (76.2 mm). This sediment along axis A causes the workpiece 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), more significant deformation is introduced into the workpiece along axis B than deformation introduced along axis A. Similarly, a subsequent impact in the direction of the axis C to reduce the size of the workpiece along the axis C to 3.0 inches (76.2 mm) introduces into the workpiece a more significant deformation along the axis C than the deformation introduced along axis A or axis B. As another example, to introduce a uniform strain In all orthogonal directions, the 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 axis C to a height of 4.0 inches (101.6 mm). This latter sequence results in a cube having approximately 4-inch ribs and containing uniform deformation in each orthogonal direction. The general equation for calculating the precipitation 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 / initial height).

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

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

-ln (upset height / source height).

Different precipitations can be achieved by using liners in the forging device that provide different precipitated heights, or in any other way known to the person skilled in the art.

[0093] According to one non-limiting embodiment of the present invention, as shown in FIG. 5 and in view of FIG. 3, the method (70) of manufacturing a titanium alloy with an ultrafine grain includes the steps according to which: beta annealing (at stage 71) of a titanium alloy billet is performed, cooled (at step 72) after beta annealing, the billet 24 to a temperature below beta transition of titanium alloy in the workpiece, heat (at step 73) the workpiece 24 to the workpiece forging temperature, which is within the temperature range of the workpiece forging, which is within the temperature range of the alpha + beta phase of the workpiece titanium alloy, and perform comprehensive forging with a high strain rate (at step 74) of the workpiece, and this comprehensive forging with a high strain rate (at step 74) includes a sub-step, according to which the forging sludge is performed along the orthogonal axes of the workpiece to different besieged heights. In one non-limiting embodiment of the implementation 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 deposited height. The phrase "pressed by forging ... to the main besieged height" used in this application refers to the forging of a workpiece on a press along an orthogonal axis to the desired final size of the workpiece along a specified orthogonal axis. Thus, the term “basic settled height” refers to the precipitated height used to achieve the final size of the workpiece along each orthogonal axis. All forging steps in the press to the main besieged heights should be performed using a strain rate sufficient to adiabatically heat the internal area of the workpiece.

[0094] After the forging (at step 75) of the workpiece 24 on the press in the direction of the first orthogonal axis A to the main besieged height, as shown in FIG. 3 (a), method (70) optionally further includes the step of allowing to cool (at step 76, shown in FIG. 3 (b)) an adiabatically heated inner region (not shown) of the workpiece to a temperature equal to or close to the forging temperature of the workpiece To her. The cooling time 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 the specialist will understand 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 period of optional cooling of the inner area, the aspect of the heating control system 33 according to the non-limiting implementation options described in this application may include the step of heating (at 77) the outer surface region 36 of the workpiece 24 to a temperature equal to the forging temperature billet or close to it. Thus, the workpiece 24 is maintained at uniform or close to uniform temperature and substantially isothermal conditions at the forging temperature of the workpiece or close to it, before each stroke of comprehensive forging with a high strain rate. According to some non-limiting implementation options, as a result of using the heating control system 33 to heat the outer surface region 36 together with allowing the adiabatically heated inner region to cool for a predetermined cooling time of the inner region, the temperature of the workpiece returns to substantially uniform temperature equal to or below the forging temperature of the workpiece. temperature between each of the forging impacts A, B and C. According to other non-limiting options, real in accordance with the present invention as a result of using the heating control system 33 to heat the outer surface region 36 together allowing the adiabatically heated inner region to cool during the specified inner region cooling time, the temperature of the workpiece returns to essentially a uniform temperature within the range of the forging temperature of the workpiece between each of forging impacts A, B and C.

[0096] According to one non-limiting embodiment, the heating (in step 77) of the outer surface region 36 of the blank 24 can be implemented using one or more external surface heating mechanisms 38 of the heating control system 33. Examples of possible surface-heating mechanisms 38 include, but are not limited to: fiery heaters configured to be heated by a flame; induction heaters, made with the possibility of induction heating; and radiant heaters configured to be heated by radiation from the blank 24. Other mechanisms and methods for heating the outer surface area of the blank will be apparent to those skilled in the art after considering 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 the surface heating mechanism 38 may include a chamber furnace (not shown). The chamber oven can be configured to use different heating mechanisms to heat the outer surface of the workpiece, and such heating mechanisms can include one or more of the 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 later.

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

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

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

[0100] The workpiece is then subjected to the next forging on a press (at step 81) along axis C for blocked precipitation to a second upset height that is greater than the main upset height. The first and second blocked sediments are used to return the workpiece essentially to its shape before forging. Although the deformation rate of the second blocked draft may be sufficient for adiabatic heating of the internal area of the workpiece, according to one non-limiting implementation variant, adiabatic heating during the second blocked draft may not be observed, since the strain introduced during the second blocked draft may not be sufficient for noticeable adiabatic heating of the workpiece. Optionally, provide (at stage 82) the possibility of cooling the adiabatically heated inner region of the workpiece to a temperature equal to or close to the forging temperature of the workpiece, while the outer surface area of the workpiece is heated (at step 83) to a temperature equal to the workpiece forging temperature or close To her.

[0101] Then, the workpiece is subjected to the following forging on a press (at step 84) in the direction of the second orthogonal axis, or axis B, for slumping to the main precipitated height. Forging on a press for precipitation to the main besieged height along the axis B (at step 84) is designated in this application as draft B. After precipitating B (at step 84), it is not necessary to allow (at step 85) cooling the adiabatically heated inner region of the workpiece to a temperature equal to or close to the forging temperature of the workpiece, while the outer surface region of the workpiece is heated (at step 86) to equal to the forging temperature of the workpiece or close to it.

[0102] Then, the workpiece is subjected to the following forging on a press (at step 87) along the C axis for blocked upsetting to a first upset height that is greater than the base upset height. Although the strain rate of the first blocked draft may be sufficient for adiabatic heating of the internal area of the workpiece, according to one non-limiting implementation variant, adiabatic heating during the first blocked draft may not be observed, since the strain introduced during the first blocked draft may not be sufficient for noticeable adiabatic heating of the workpiece. Optionally, provide (at step 88) the possibility of cooling the adiabatically heated inner region of the workpiece to a temperature equal to or close to the forging temperature of the workpiece, while the outer surface area of the workpiece is heated (to step 89) to a temperature equal to the temperature of the forging workpiece or close To her.

[0103] Then, the billet is subjected to the following forging on a press (at step 90) along axis A for blocked sediment to a second precipitated height that is greater than the principal precipitated height. The first and second blocked sediments are used to return the workpiece essentially to its shape before forging. Although the deformation rate of the second blocked draft may be sufficient for adiabatic heating of the internal area of the workpiece, according to one non-limiting implementation variant, adiabatic heating during the second blocked draft may not be observed, since the strain introduced during the second blocked draft may not be sufficient for noticeable adiabatic heating of the workpiece. Optionally, provide (at step 91) the possibility of cooling the adiabatically heated inner region of the workpiece to a temperature equal to or close to the forging temperature of the workpiece, while the outer surface area of the workpiece is heated (at step 92) to a temperature equal to the workpiece forging temperature or close To her.

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

[0105] The workpiece is then subjected to the next forging on a press (at step 96) along axis A for blocked upsetting to a first upset height that is greater than the main upset height. Although the strain rate of the first blocked draft may be sufficient for adiabatic heating of the internal area of the workpiece, according to one non-limiting implementation variant, adiabatic heating during the first blocked draft may not be observed, since the strain introduced during the first blocked draft may not be sufficient for noticeable adiabatic heating of the workpiece. Optionally, provide (at step 97) the possibility of cooling the adiabatically heated inner region of the workpiece to a temperature equal to or close to the forging temperature of the workpiece, while the outer surface area of the workpiece is heated (98) to a temperature equal to or close to the forging temperature To her.

[0106] The workpiece is then subjected to the next forging on a press (at step 99) along the B axis for blocked sediment to a second upset height that is larger than the main upset height. The first and second blocked sediments are used to return the workpiece essentially to its shape before forging. Although the deformation rate of the second blocked draft may be sufficient for adiabatic heating of the internal area of the workpiece, according to one non-limiting implementation variant, adiabatic heating during the second blocked draft may not be observed, since the strain introduced during the second blocked draft may not be sufficient for noticeable adiabatic heating of the workpiece. Optionally, provide (at step 100) the possibility of cooling the adiabatically heated inner region of the workpiece to a temperature equal to or close to the forging temperature of the workpiece, while the outer surface area of the workpiece is heated (at 101) to a temperature equal to the temperature of the forging workpiece or close To her.

[0107] As shown in FIG. 5, according to non-limiting implementation options, one or more steps (75), (78), (81), (84), (87), (90), (93), (96) and (99) press forging is repeated (at step 102), until the degree of total deformation of the titanium alloy in the specified billet is at least 1.0. According to another non-limiting embodiment of the implementation of one or more stages (75), (78), (81), (84), (87), (90), (93), (96) and (99) forging on the press is repeated ( at step 102) until a total strain in the range of at least 1.0 to less than 3.5 is achieved in a titanium alloy billet. It should be understood that after reaching the desired 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 in any of steps (75), (78), ( 81), (84), (87), (90), (93), (96) and (99) press forging optional intermediate equilibration steps (i.e., steps (76), (79), (82 ), (85), (88), (91), (94), (97) or (100), according to which the internal area of the workpiece can be cooled, 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 may be cooled to ambient temperature. According to one non-limiting embodiment, cooling involves quenching in a liquid, such as, for example, quenching in water. In another non-limiting embodiment, cooling involves cooling at a rate of cooling by air flow or faster cooling.

[0108] The process described above involves re-sequence of forging on a press for slumping to a main besieged height, followed by forging on a press for a blocked slump to the first and second besieged heights. The forging sequence, which is one complete cycle of comprehensive forging, described above in a non-limiting implementation, can be represented as forging operations A -BC- B- CA- C -AB, with operations (blows) that are indicated in bold and underlined. they are intended for precipitations up to the main upset height, and operations that are not indicated in bold and not underlined are the first or second blocked precipitations. It should be understood that all press forging deposits, including press forging operations for upsetting to the main besieged 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 for adiabatic heating of the inner region of the workpiece 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 in essence may not occur during the first and second blocked sediments due to the lower degree of deformation during these sediments compared to the main sediments. You should also understand that between successive forging sediments, as optional, there are stages in which provide the ability to cool the adiabatically heated inner region of the workpiece to a temperature equal to or close to the forging temperature of the workpiece and to heat the outer surface of the workpiece to a temperature equal to 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 sizes. Additionally, it is implied that the forging operations sequence A -BC- B -CA- C -AB according to the embodiment described in this application can be repeated in whole or in part until the degree of total deformation of at least 1.0 or in the range from at least measure 1.0 to less than 3.5.

[0109] A bulging in a workpiece is the result of a combination of blocking a surface with a die and the presence of a hotter material in the center of the workpiece. With an increase in buckling, the center of each surface is exposed to increasing volume loads that can initiate cracking. In the A -BC- B- CA- C -AB sequence, the use of blocked sediment between each forging operation on a sediment press to the main upset height reduces the tendency for cracking in the workpiece. According to one non-limiting implementation variant, if the billet has the shape of a cube, the first blocked sediment to the first upset height can be made up to an upset height that is 40-60% larger than the main upset height. According to one non-limiting implementation variant, if the billet is in the form of a cube, the second blocked draft to the second upset height can be completed up to the upset height that is 15-30% larger than the main upset height. According to another non-limiting embodiment, the first precipitated height with blocked draft may be substantially equivalent to the second precipitated height with blocked draft.

[0110] In non-limiting embodiments of heat-controlled all-round forging with a high strain rate according to the present invention, after a total strain to a degree of at least 1.0 or in a range from at least 1.0 to less than 3.5, the average grain size alpha particles in the workpiece is 4 microns or less, which is believed to be ultra-fine grain size (UFG). According to one non-limiting embodiment of the present invention, the use of 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 equiaxial.

[0111] According to one non-limiting embodiment of the method according to the present invention, which includes forging and using an optional heating control system, the working surface of the press-forming workpiece is lubricated with known lubricants, such as inter alia graphite, glass lubricant and / or other known consistent lubricants.

[0112] According to some non-limiting embodiments of the methods of the present invention, the preform comprises a titanium alloy selected from two-phase titanium alloys with an alpha-beta structure and metastable titanium beta alloys. According to another non-limiting implementation variant, the preform comprises a two-phase titanium alloy with an alpha beta structure. According to another non-limiting embodiment, the preform comprises a metastable beta-titanium alloy. According to one non-limiting implementation variant, 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 Ti-6-4 alloy (UNS R56400), and such kinetics can be designated in this application as "slower alpha kinetics". According to one non-limiting implementation variant, slower alpha kinetics can be achieved if the diffusion capacity of the most slowly diffusing constituent particles in a titanium alloy is slower than the diffusion capacity of aluminum in the Ti-6-4 alloy at the (T _β ) beta transition. For example, Ti-6-2-4-2 alloy has a slower alpha kinetics than Ti-6-4 alloy, as a result of the presence of additional stopping grain elements, such as silicon, in Ti-6-2-4-2 alloy . In addition, Ti-6-2-4-6 alloy has a slower alpha kinetics than Ti-6-4 alloy, as a result of the presence of additional beta-phase stabilizing additives in the alloy, such as molybdenum, the content of which in this alloy is higher than alloy T-6-4. The result of a 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 strain rate allows for relatively small and stable the size of the alpha package and the fine structure of the beta phase compared with the Ti-6-4 alloy and some other titanium alloys that have a faster release of the alpha phase 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 the embodiments of the methods of the present invention include, among others, Ti-6-2-4-2 alloy, Ti-6-2-4-6 alloy, ATI 425 ^® alloy (Ti alloy 4Al-2,5V), alloy Ti-6-6-2 and alloy Ti-6Al-7Nb.

[0113] A non-limiting embodiment of the method according to the present invention includes the steps of beta annealing, according to which: the billet is heated to a beta annealing temperature; phase of titanium in the workpiece, and cool the workpiece directly to a temperature equal to the temperature of forging the workpiece or close to it. In some non-limiting embodiments, the temperature of the beta annealing is in the range of temperatures from the beta transition temperature of the titanium alloy to a temperature that is 300 ° F (111 ° C) above the beta transition temperature of the titanium alloy. According to non-limiting implementation options, the beta annealing time is from 5 minutes to 24 hours. It will be clear to the skilled person after reading this disclosure that other beta annealing temperatures and beta annealing times also fall within the protection scope of embodiments of the present invention, and, for example, relatively large workpieces may require relatively elevated beta annealing temperatures and / or longer beta annealing times to form the 100% microstructure of the beta phase of titanium.

[0114] According to some non-limiting embodiments, in which the billet is maintained at the beta annealing temperature to form a 100% beta phase microstructure, the billet can also be plastically deformed at the plastic deformation temperature in the beta phase phase of the titanium alloy prior to cooling the billet to a temperature equal to or near the forging temperature of the workpiece, or to ambient temperature. Plastic deformation of the workpiece may contain at least one of drawing, forging draft and all-round forging with a high rate of deformation of the workpiece. According to one non-limiting implementation variant, plastic deformation in the beta-phase region includes forging the draft preform to a degree of deformation due to precipitation in the beta-phase region in the range from 0.1 to 0.5. According to some non-limiting implementation options, the temperature of plastic deformation is in the range of plastic deformation temperatures from the temperature of the beta transition of the titanium alloy to a temperature of 300 ° F (111 ° C) above the temperature of the beta transition of the titanium alloy inclusive.

[0115] FIG. 6 shows the temperature-time graph of thermomechanical processing by a non-limiting method of plastic deformation of the workpiece above the beta transition temperature and direct cooling to the workpiece forging temperature. As shown in FIG. 6, the non-limiting method 200 includes a step 202 in which a billet of a titanium alloy having an alpha release and growth kinetics is heated that is slower than that of a Ti-6-4 alloy, for example, to a temperature of 204 beta annealing that is higher than 206 a beta transition of the titanium alloy, and a step 208, in which the billet is held or “worn” at a temperature of 204 beta annealing to form the microstructure completely with the beta phase of titanium in the billet. According to one non-limiting embodiment of the present invention after languishing at step 208, the workpiece can be plastically deformed at step 210. According to one non-limiting implementation variant, step 210 of plastic deformation involves forging with sediment. According to one non-limiting implementation variant, the step 210 of plastic deformation includes forging the draft to a true deformation of 0.3. According to one non-limiting implementation variant, the step 210 of plastic deformation includes heat-controlled all-round forging with a high strain rate (not shown in FIG. 6) at a 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 workpiece is cooled in step 212 to the workpiece forging temperature 214 in the alpha + beta phase of the titanium alloy. According to one non-limiting embodiment, the cooling in step 212 comprises cooling with a rate of cooling by air flow or faster cooling. According to another non-limiting embodiment, cooling involves 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 temperature of 214 with a high strain rate in accordance with some non-limiting embodiments of the present invention. According to one non-limiting embodiment, as shown in FIG. 6, the workpiece is hit or hammered on the press 12 times, i.e. along three orthogonal axes, the workpieces are inconsistently pressed 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 sequence of all-round forging consisting of 12 strokes, the total strain may be, for example, at least 1.0, or it may be in the range of at least 1.0 to less than 3.5. After all-round forging in step 214, the workpiece is cooled in step 216 to ambient temperature. In one non-limiting implementation, cooling in step 216 involves cooling at an air flow rate or faster cooling, but other forms of cooling, such as, among other things, quenching in a fluid or liquid, also fall within the protection scope of the embodiments of the present invention described in application.

[0117] A non-limiting aspect of the present invention includes comprehensive forging with a high strain rate at two temperatures in the alpha + beta phase. FIG. 7 shows a time-temperature graph of thermomechanical processing in a non-limiting manner according to the present invention, including the steps of performing a comprehensive forging of a titanium alloy billet at the first forging temperature of the workpiece, optionally using a non-limiting embodiment of the means for thermal control described above, is cooled to the second temperature of the forging of the workpiece in the alpha + beta phase, perform a comprehensive forging of a titanium alloy billet at a 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 of the present invention includes the steps of heating a billet to a temperature of 234 beta annealing in step 232, which is higher than the alloy’s 236 beta transition temperature and is held or brazed in a 238 block at 234 beta annealing to form billet of titanium alloy microstructure, completely consisting of a beta phase. After languishing at step 238, the workpiece may be plastically deformed at step 240. According to one non-limiting implementation variant, plastic deformation at step 240 includes forging draft. According to another non-limiting implementation variant, plastic deformation at step 240 includes forging a draft to a degree of deformation of 0.3. According to another non-limiting embodiment, the plastic deformation of the workpiece in step 240 includes all-round forging with a high strain rate (not shown in FIG. 7) at a beta annealing temperature.

[0119] As shown in FIG. 7, after plastic deformation at step 240 in the beta-phase region, the workpiece is cooled in step 242 to the first forging temperature of the workpiece 244 in the alpha + beta phase of the titanium alloy. According to non-limiting implementation options, cooling in step 242 includes one of air cooling and hardening in a liquid. After cooling in step 242, the workpiece is subjected to comprehensive forging in step 246 with a high strain rate at the first forging temperature of the workpiece, and the heating control is not necessarily used according to the non-limiting implementation options described in this application. According to one non-limiting embodiment shown in FIG. 7, the workpiece is hit or hammered on the press at the first forging temperature of the workpiece 12 times with a 90 ° rotation between blows, i.e., along three orthogonal axes, the workpiece is hammered 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 workpiece with a high strain rate in step 246, at the first forging temperature, the titanium alloy billet is cooled in step 248 to the second forging temperature of the workpiece in step 250 in the alpha + beta phase. After cooling in step 248, the billet is subjected to comprehensive forging 250 with a high strain rate at the second forging temperature of the billet and optionally using a heating control system according to the non-limiting embodiments described in this application. 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 a total of 12 times. It should be understood that the number of impacts on the titanium alloy billet at the first and second forging temperatures of the billet can be changed depending on the required true deformation and the required final grain size, and the number of impacts that is suitable can be determined without undue experimentation inventions. After all-round forging in step 250 at the second forging temperature, the workpiece is cooled in step 252 to ambient temperature. According to non-limiting implementation options, the cooling in step 252 includes one of air cooling and quenching in the liquid to ambient temperature.

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

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

[0122] Since all-round forging steps 270, 272, 274 are performed while cooling the billet to temperatures below the beta transition temperature of the titanium alloy, the method according to one embodiment shown in FIG. 8, in this application, is referred to as "all-round forging with a high strain rate with intersection of the beta transition." According to one non-limiting implementation variant, the heating control system 33 (as shown in FIG. 3) is used in comprehensive forging with a beta transition to maintain the workpiece at a uniform or substantially uniform temperature before each impact at each forging temperature with a beta transition and optional to slow down the cooling rate. After the final stage 274 of comprehensive forging, which is performed at the forging temperature of the workpiece in the alpha + beta phase region, the workpiece 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 the comprehensive forging using the heating control system described above can be used to process titanium alloy billets with cross sections greater than 4 square meters. inches (25.8 cm ² ), using well-known forging equipment, and the size of the billet having a cubic shape can be scaled to fit the characteristics of a particular press. It was determined that alpha-lamellae or packets from the β-annealed structure easily crumble to fine homogeneous alpha grain at the forging temperatures of the workpiece according to the non-limiting implementation options described in this application. Also, it was determined that lowering the forging temperature of the workpiece leads to a decrease in the size of alpha particles (grain size).

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

[0125] Alternative methods according to the present invention were further developed, providing several advantages over the method described above, which includes forging using a heating control system and a cube-shaped billet 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 heat-controlled all-round forging described in this application, (2) stamp cooling (i.e., the possibility of reducing the temperature of the dies is well below 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 may contribute to achieving a generally homogeneous fine grain, very fine grain, or an ultra-fine grain size throughout the entire billet of a varietal size of titanium alloy. In other words, a billet processed by such alternative methods may have the required grain size, such as superfine, throughout the volume of the billet, and not only in its central region. Non-limiting embodiments of such alternative methods include the steps of "multiple sludge and stretching" applied to blanks with cross sections greater than 4 square meters. inches (25.8 cm ² ). The multiple stages of precipitation and drawing are designed to create a microstructure with a uniform fine grain, a very fine grain, or an ultra fine grain throughout the billet while maintaining essentially the original dimensions of the blank. Since such alternative methods include multiple stages of precipitation and drawing, they are referred to in this application as embodiments of the method of multiple draft 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 varietal size (for example, 30 inches (76.2 cm) in length) from a titanium alloy. According to non-limiting embodiments of the method of multiple precipitation and drawing (MUD) according to the present invention, the indicated strain rates used in the forging steps of the draft and drawing forging are in the range of 0.001 s ⁻¹ to 0.02 s ⁻¹ . In contrast, the strain rates typically used in the stages of known open-draft forging and drawing forging are in the range of 0.03 s ^-1 to 0.1 s ^-1 . The rate of deformation during repeated precipitation and stretching is sufficiently slow to prevent the adiabatic heating of the workpiece while keeping the forging temperature under control, but still the indicated strain rate is acceptable for commercial applications.

[0127] A schematic representation of the non-limiting embodiments of the Multi Draft & Exhaust (MUD) method is shown in FIG. 9, and a block diagram of some embodiments of the multiple draft and exhaust (MUD) process is shown in FIG. 10. As shown in FIG. 9 and 10, a non-limiting method 300 for grinding grains in a billet containing a titanium alloy using forging steps with multiple draft and drawing, involves heating the elongated billet 302 of titanium alloy to a forging temperature in the alpha + beta phase of the titanium alloy . According to one non-limiting embodiment, the elongated workpiece has the shape of a cylinder or a shape similar to the shape of a cylinder. According to another non-limiting embodiment, the preform has the shape of an octagon or a regular octagon.

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

[0129] When the elongated billet is at the forging temperature of the billet, the billet is hammered by sludge at step 304. After sludge forging at step 304 according to one non-limiting implementation, the workpiece is rotated 90 ° until orientation 306 is reached and then subjected to multi-pass forging with hood at step 312. Actual rotation of the workpiece is optional, and the task of this stage is to locate the workpiece in the correct orientation (as shown in Fig. 9) relative to the device for forging followed by multipass to exhaust hood at step 312.

[0130] Multi-pass forging with hood involves rotation with increment (indicated by arrow 310) of the workpiece in the direction of rotation (indicated by arrow 310), followed by forging with hood during step 312 of the workpiece after each increment of rotation. According to non-limiting embodiments, the rotation with increment at step 310 and the forging with hood at step 312 are repeated until the workpiece returns to its original transverse dimension. According to one non-limiting implementation variant, the steps of forging a draft and a multi-pass forging by drawing 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, forging a deposit, and multi-pass forging with a hood until a total strain in the range from at least 1.0 to less than 3.5 is achieved in the workpiece. According to another non-limiting implementation variant, the steps of heating, forging with sediment and multi-pass forging with hoods are repeated until a total strain of at least 10 is achieved in the workpiece. It is expected that when the forging with a multiple draft and hood in the workpiece has been achieved, total strain 10 is achieved in the workpiece an ultrafine alpha microstructure is formed, and an increase in the total strain introduced into the workpiece results in a decrease in the average grain size.

[0131] According to one aspect of the present invention, the strain rate should be used during the precipitation and multipass stretching stages, which is sufficient to lead to severe plastic deformation of the titanium alloy blank, which, according to non-limiting implementation options, additionally leads to the formation of an ultra-fine grain. According to one non-limiting embodiment, the strain rate used in forging the draft is in the range of 0.001 s ^-1 to 0.003 s ^-1 . According to another non-limiting implementation variant, the strain rate used in multi-pass forging with stretching is in the range from 0.01 s ^-1 to 0.02 s ^-1 . The '538 Application describes that the strain 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, after completion of the multiple draft and exhaust (MUD) method, the blank has substantially the initial dimensions of the original elongated product, such as, for example, a cylinder 314 or an octahedron 316. According to another non-limiting embodiment, after completion of the multiple draft method The hood (MUD) billet has essentially the same cross section as the original billet. According to one non-limiting implementation variant, a single draft requires that multiple blows of the hood and intermediate rotations return the blank to a shape having an initial cross-section of the blank.

[0133] According to one non-limiting embodiment of the method of multiple precipitation and drawing (MUD), in which the workpiece, for example, has the shape of a cylinder, rotation with increment and forging by exhaust, additionally include multiple stages of rotation of the cylindrical workpiece with increments of 15 ° followed by forging with exhaust, until the cylindrical billet rotates 360 ° with a forged hood at each increment. According to one non-limiting embodiment of the method of multiple precipitation and drawing (MUD), in which the billet has the shape of a cylinder, after each draft forging, the twenty-four steps of forging the hood with intermediate rotation with increment between successive stages of forging are applied to bring the workpiece to its original transverse dimension. exhaust hood. According to another non-limiting embodiment in which the billet has the shape of an octagonal cylinder, rotation with increment and forging with hood also include multiple stages of rotation of the cylindrical billet in increments of 45 ° and subsequent forging with a hood until the cylindrical billet rotates 360 ° with forging with a hood at each increment. According to one non-limiting embodiment of the method of multiple precipitation and drawing (MUD), in which the workpiece has the shape of an octahedron, after each forging draft to bring the workpiece essentially to its original transverse size, eight forging steps are used, separated by rotation with the workpiece increment. In non-limiting embodiments of the method of multiple draft and exhaust (MUD), it was observed that the manipulation of the octahedron by means of loading and unloading equipment turned out to be more accurate than the manipulation of the cylinder by loading and unloading equipment. It was also observed that the manipulation of the octahedron by loading and unloading equipment according to one non-limiting embodiment of the method of multiple precipitation and stretching (MUD) turned out to be more accurate than the manipulation of a cube-shaped workpiece using manual tongs according to non-limiting options for implementing a heat-controlled method of comprehensive high-quality forging strain rate described in this application. It should be understood when considering the present description that other forging with hoods, each of which may contain multiple stages of forging with hood and intermediate rotations in increments of a specific number of degrees, can be used for blanks having different cross-sectional shapes so that the final shape the billet after forging by stretching is essentially the same as the original form of the billet prior to forging a draft. These other possible sequences can be determined by a specialist without undue experimentation and should be considered as falling within the protection scope of the present invention.

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

[0135] According to one non-limiting embodiment of the method of multiple precipitation and drawing (MUD) according to the present invention, a forging temperature range of a billet for Ti-6-2-4-2 alloy that has a beta transition temperature (T _β ) of about 1820 ° F ( 993.3 ° C), may 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] The non-limiting embodiments of the multiple draft and exhaust (MUD) process include multiple reheating steps. According to one non-limiting implementation variant, the titanium alloy billet is heated to the forging temperature of the billet after forging a billet of titanium alloy. According to another non-limiting implementation variant, the titanium alloy billet is heated to the forging temperature of the billet before the forging stage of a multi-pass forging by drawing. According to another non-limiting implementation variant, the billet is heated, if necessary, to return the actual temperature of the billet to a temperature close to the forging temperature of the billet, after a forging step or drawing forging.

[0137] It was determined that embodiments of the method of multiple precipitation and stretching (MUD) lead to excessive work or excessive deformation, which can also be called intense plastic deformation, which is aimed at creating superfine grains in a titanium alloy-containing billet. Without deepening into a particular theory of operation, it is assumed that the round or octagonal cross-sectional shape of cylindrical and octahedral cylindrical blanks, respectively, contributes to a more uniform distribution of deformation than the distribution of deformation in billets with square or rectangular cross-sectional shape during processing method of multiple precipitations and exhaust (MUD). 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 has also been further determined that reducing the temperature during processing with the multiple precipitation and stretching method (MUD) helps to reduce the final grain size to a size that is characteristic of the desired temperature used. As shown in FIG. 10, according to one non-limiting embodiment of the method 400 of grinding the grain size of a workpiece after treating said workpiece with a multiple draft and drawing (MUD) method at a forging temperature, said workpiece can be cooled at step 416 to a second forging temperature of the workpiece. According to one non-limiting embodiment, after cooling the billet to the second forging temperature, said billet is forged by draft at step 418 at the second forging temperature of the billet. At step 420, the workpiece is rotated or otherwise oriented relative to the forging press to perform the subsequent forging steps with a hood. At step 422, multiple forging steps are applied to the workpiece at a second forging temperature of the workpiece. Multi-stage forging with a hood at the second forging temperature of the workpiece at step 422 includes rotation with increment at step 424 of the workpiece in the direction of rotation (as shown in Fig. 9) and forging with hood at the second forging temperature at step 426 after each increment of rotation. According to one non-limiting implementation variant, the steps of precipitation, rotation with increment at step 424 and forging with exhaust hood at step 426 are repeated until the workpiece returns to its original transverse size. According to another non-limiting implementation variant, the steps of forging the draft at the second temperature of the workpiece at step 418, rotation at step 420 and multiple forging with hood at step 422 are repeated until the total strain in the workpiece is at least 1.0 or the strain in the range from 1.0 to less than 3.5, or up to 10 or more. It is believed that the multiple draft and exhaust (MUD) process can be continued until any necessary total deformation is imparted to the titanium alloy blank.

[0139] According to one non-limiting embodiment comprising an embodiment of the multi-temperature multiple draft and stretching method (MUD), the forging temperature of the workpiece, or the first forging temperature of the workpiece, is about 1600 ° F (871.1 ° C), and the second forging temperature of the workpiece is approximately 1500 ° F (815.6 ° C). Subsequent forging temperatures of the workpiece that are lower than the first and second forging temperatures of the workpiece, such as the third forging temperature of the workpiece, the fourth forging temperature of the workpiece, etc., fall within the protection scope of the non-limiting embodiments of the present invention.

[0140] As the forging is performed, the grinding of the grain leads to a decrease in the plastic flow stress at a fixed temperature. It was determined that a decrease in the forging temperature for successive stages of precipitation and drawing keeps the flow of plastic flow constant and increases the speed of microstructural grinding. It is expected that, according to non-limiting options for implementing multi-draft and stretching (MUD) according to the present invention, total strain to a degree of at least 1.0, in the range from at least 1.0 to less than 3.5, or to degree 10 results to a homogeneous equiaxial ultrafine-grained alpha microstructure in titanium alloy billets, and the lower temperature in the multiple precipitation and stretching (MUD) method with two temperatures (or multiple temperatures) can be determined from the final grain size after implanting A total strain to degree 10 during forging with multiple sedimentation and stretching (MUD).

[0141] The aspect of the present invention includes the ability to perform post-processing of the workpiece by means of multiple precipitations and stretching (MUD) of subsequent deformation steps without consolidating the crushed grain size until the temperature of the workpiece is heated above the titanium alloy beta transition temperature. For example, according to one non-limiting implementation, the steps of deforming, subsequent to performing the multiple precipitation and stretching method (MUD), may include forging by drawing, multiple forging by drawing, drawing forging or any combination of two or more of the above forging methods at temperatures in the alpha + beta region titanium alloy phases. According to one non-limiting embodiment, the subsequent deformation or forging steps include a combination consisting of multi-pass drawing forging, draft forging and drawing forging to reduce the original cross-sectional size of a cylinder-like or other elongated workpiece to a fraction of the cross-sectional size, such as, for example, among other things half of the transverse size, one quarter of the transverse size, and the like, while maintaining a homogeneous structure of fine grain, very fine grain or superfine th grain in the billet of titanium alloy.

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

[0143] Before heating the workpiece to the forging temperature of the workpiece in the alpha + beta phase according to the embodiments of the multiple draft and stretching method (MUD) according to the present invention, in a non-limiting embodiment, the workpiece can be heated to the beta annealing temperature, maintained at a beta temperature annealing during beta-annealing, sufficient to form a microstructure in the billet with a 100% beta phase of titanium, and cooled to ambient temperature. According to one non-limiting embodiment, the beta annealing temperature is in the beta annealing temperature range from the beta transition temperature of the titanium alloy to a temperature that is 300 ° F (111 ° C) above 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 workpiece is an ingot, all or some of whose surfaces are coated with a lubricating coating that reduces the friction between the workpiece and the forging dies. According to one non-limiting implementation, the lubricating coating is a grease, including but not limited to one of graphite and glass lubricant. Other lubricating coatings that are currently known or that will be known later fall within the protection scope of the present invention. In addition, according to one non-limiting embodiment of the method of multiple precipitation and stretching (MUD), which uses cylinder-like or other elongated billet forms, the contact area between the billet and forging dies is small compared to the contact area for all-round forging of a billet having the form Cuba. For example, in the case of a cube with a 4 inch edge (101.6 mm), two of all cube surfaces measuring 4 × 4 inches (101.6 × 101.6 mm) are in contact with the punch. In the case of an ingot 5 feet long (1520 mm), the ingot length is greater than the length of a typical die 14 inches long (350 mm), and a reduction in contact area leads to a reduction in friction of the die and to a more uniform microstructure and macrostructure of the titanium alloy billet.

[0145] Before heating a billet containing a titanium alloy to the forging temperature of the billet in the alpha + beta phase according to the embodiments of the method of multiple precipitation and drawing (MUD) according to the present invention, according to one non-limiting implementation variant, the billet is deformed plastically at the temperature of plastic deformation the region of the beta phase of the titanium alloy with simultaneous incubation for a period of beta annealing, sufficient for the formation of a 100% beta phase in the titanium alloy, and before cooling sp Ava to ambient temperature. According to one non-limiting implementation variant, 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 range of temperatures of plastic deformation from the temperature of the beta transition of the titanium alloy to a temperature that is 300 ° F (111 ° C) above the temperature of the beta transition of the titanium alloy.

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

[0147] Another aspect of the multiple draft and stretch (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 to forge the workpiece to a temperature in the range of temperatures from the forging temperature of the workpiece to a temperature that is 100 ° F (55.6 ° C) below the forging temperature of the workpiece.

[0148] According to non-limiting embodiments of the method of multiple precipitation and stretching (MUD) according to the present invention, the method of manufacturing titanium alloys with ultrafine grains includes the steps according to which: a titanium alloy having a slower alpha release and growth kinetics than Ti-6 is selected -4, perform beta-annealing of the alloy to ensure a fine-grained and stable structure of the alpha package and perform a comprehensive forging of the alloy with a high strain rate according to the present invention to a 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 assumed that some of the methods described in this application can also be applied to metals and metal alloys in addition to titanium alloys to reduce the grain size in blanks made from these alloys. Another aspect of the present invention contains non-limiting embodiments of a multi-stage forging process with a high strain rate of metals and metal alloys. A non-limiting embodiment of this method involves heating a billet containing a metal or a metal alloy to the forging temperature of the billet. After heating, the billet is forged at the forging temperature of the billet with a deformation rate sufficient to adiabatically heat the inner region of the billet. After forging, a waiting period is used before the next forging step. During this waiting period, it is possible to cool the adiabatically heated inner region of the metal alloy billet to the forging temperature of the billet by heating at least one surface area of the billet to the forging temperature of the billet. The forging steps of the billet and the subsequent provision of the possibility of balancing the adiabatically heated inner region of the billet to the forging temperature of the billet when heating at least one surface area of the metal alloy billet to the forging temperature of the billet is repeated to obtain the required characteristics. According to one non-limiting embodiment, forging comprises at least one of press forging, draft forging, stretch forging, and forging by rolling. According to another non-limiting implementation variant, the metal alloy is selected from the group consisting of titanium alloys, zirconium and zirconium alloys, aluminum alloys, iron alloys and superalloys. According to another non-limiting implementation variant, the desired characteristic is at least one of the attributed deformation, 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 implementation options without limiting the scope of protection of the present invention. It will be clear to the skilled person that possible changes to the following examples fall within the protection scope of the present invention, as defined in the claims of the claims.

EXAMPLE 1

[0151] The bar of Ti-6-2-4-2 alloy was processed by a known forging method, designated in industry by the standard AMS 4976, which is commonly used for machining Ti-6-2-4-2 alloy. From the AMS 4976 standard, the specialist will understand the specific features of the process for achieving mechanical properties and microstructure as 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 prepared alloy shown in FIG. 11 (a), the microstructure contains alpha grains (light colored areas in the image) that are about 20 microns or larger in size.

[0152] According to a non-limiting embodiment of the present invention, a cube-shaped billet with a side of 4.0 inches (101.6 mm) of Ti-6-2-4-2 alloy was subjected to beta annealing at a temperature of 1950 ° F (1066 ° C) for 1 hour and then cooled in air to ambient temperature. After cooling, the beta-annealed billet in the form of a cube was heated to a forging temperature of 1600 ° F (871.1 ° C) and forged using four blows by the method of comprehensive forging with a high strain rate. The blows were performed in the direction of the following orthogonal axes and in the following sequence: ABCA. As a result of the blows, an upset height of 3.25 inches (88.9 mm) was reached, 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 edge (101.6 mm), this plunger speed leads to a minimum strain rate during pressing, which is 0.25 s ^-1 . The time between subsequent orthogonal strikes was approximately 15 seconds. The degree of total deformation attributed to the workpiece was 1.37. The microstructure of the Ti-6-2-4-2 alloy treated in this way is shown in the micrograph in FIG. 11 (b). Most of the alpha particles (light colored areas) have a size of about 4 microns or less, which is essentially a 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] The bar of Ti-6-2-4-6 alloy was processed by a known forging method commonly used for alloy T-6-2-4-6, i.e., according to AMS 4981. From AMS 4976, specialist will understand the specific features of the process of achieving 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 about 10 microns or larger.

[0154] According to one non-limiting embodiment of the present invention, a cube-shaped billet with a side of 4.0 inches (101.6 mm) of Ti-6-2-4-6 alloy was subjected to beta annealing at a temperature of 1870 ° F (1066 ° C ) for 1 hour and then cooled in air. After cooling, the beta-annealed billet in the form of a cube was heated to a forging temperature of 1500 ° F (815.6 ° C) and forged using four blows using a comprehensive forging method with a high strain rate. The blows were performed in the direction of the following orthogonal axes and in the following sequence: ABCA. As a result of the blows, an upset height of 3.25 inches (88.9 mm) was reached, 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 edge (101.6 mm), this plunger speed leads to a minimum strain rate during pressing, which is 0.25 s ^-1 . The time between subsequent orthogonal strikes was approximately 15 seconds. The degree of total deformation attributed to the workpiece was 1.37. The microstructure of the alloy thus treated is shown in the micrograph in FIG. 12 (b). It can be noted that most of the alpha particles (light colored areas) are about 4 microns or less in size and in any case represent a much smaller grain than the alpha grain 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 cube-shaped billet with a side of 4.0 inches (101.6 mm) of Ti-6-2-4-6 alloy was subjected to beta annealing at a temperature of 1870 ° F (1066 ° C ) for 1 hour and then cooled in air. After cooling, the beta-annealed billet in the form of a cube was heated to a forging temperature of 1500 ° F (815.6 ° C) and forged using three blows using a comprehensive forging method with a high deformation rate with one blow along each axis A, B and C (t. e., impacts were performed in the direction of the following orthogonal axes and in the following sequence: ABC). As a result of the blows, an upset height of 3.25 inches (88.9 mm) was reached, 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 edge (101.6 mm), this plunger speed leads to a minimum strain rate during pressing, which is 0.25 s ^-1 . The time between subsequent orthogonal strikes was approximately 15 seconds. After the ABC blows cycle, 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 stroke along each of the axes A, B and C, i.e., the punches were performed along the following orthogonal axes and in the following sequence: ABC. As a result of the blows, the same seated height was achieved, and the same plunger speed and time between blows were used as in the first ABC blow sequence. After the second ABC sequence, the billet 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 strain rate with one stroke along each of the A, B and C axes, i.e., the ABC sequence was used. As a result of the blows, the same seated height was achieved, and the same plunger speed and time between blows were used as in the first ABC blow sequence. As a result of this embodiment of the method of comprehensive forging with a high strain rate, a deformation of 3.46 was given to the workpiece. The microstructure of the alloy thus treated is shown in the micrograph in FIG. 13. It can be observed that most alpha particles (light colored areas) are about 4 microns or smaller. It is assumed that, in all likelihood, alpha particles consist of individual alpha grains, and that each alpha grain has a size of about 4 microns or less and is equiaxial in shape.

EXAMPLE 4

[0156] According to one non-limiting embodiment of the present invention, a cube-shaped billet with a side of 4.0 inches (101.6 mm) of Ti-6-2-4-2 alloy was subjected to beta annealing at a temperature of 1950 ° F (1066 ° C ) for 1 hour and then cooled in air. After cooling, the beta-annealed billet in the form of a cube was heated to a forging temperature of 1700 ° F (926.7 ° C) and held for 1 hour. Two cycles of comprehensive forging with a high strain rate were used (2 sequences of three ABC impacts, totaling 6 impacts) at a temperature of 1700 ° F (926.7 ° C). The time between successive strikes was approximately 15 seconds. The forging sequence was as follows: kick A using a 3-inch (76.8 mm) stop; kick B using a 3.5-inch (89.6 mm) stopper; and hit C using a 4.0-inch (102.4 mm) stopper. This forging sequence ensures equal deformation along all three orthogonal axes in each comprehensive forging sequence of three 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 edge (101.6 mm), this plunger speed leads to a minimum strain rate during pressing, which is 0.25 s ^-1 . The total strain per cycle was less than forging to 3.25-inch (83.2 mm) precipitations in each direction, as in the previous examples.

[0157] The workpiece 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 blows (i.e., one additional cycle A-B-C of comprehensive forging with a high deformation rate). The forging sequence was as follows: kick A using a 3-inch (76.8 mm) stop; kick B using a 3.5-inch (89.6 mm) stopper; and hit C using a 4.0-inch (102.4 mm) stopper. After forging, the total deformation attributed to the workpiece was 2.59.

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

EXAMPLE 5

[0159] According to one non-limiting embodiment of the present invention, a cube-shaped billet with a side of 4.0 inches (101.6 mm) of Ti-6-2-4-2 alloy was subjected to beta annealing at a temperature of 1950 ° F (1066 ° C ) for 1 hour and then cooled in air. After cooling, the beta-annealed billet in the form of a cube was heated to a forging temperature of 1700 ° F (926.7 ° C) and held for 1 hour. A comprehensive forging according to the present invention was used to apply to a billet having the shape of a cube, 6 forgings on a sludge press to the main upset height ( A , B , C , A , B , C ). In addition, for the "squareing" of the workpiece between each forging on the press, the first and the second blocked sediments along the other axes were made for the draft up to the main deposited height of 3.25 inches (82.55 mm). The following general forging sequence was used, in which bold and underlined symbols denote forging on a press for upsetting to the main besieged height: A -BC- B -CA- C -AB- A -BC- B- CA- C .

[0160] The forging sequence, including the used primary, first blocked, and second blocked besieged heights (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 edge (101.6 mm), this plunger speed leads to a minimum strain rate during pressing, which is 0.25 s ^-1 . The time elapsed between hits was approximately 15 seconds. The degree of total deformation after heat-controlled all-round forging according to this non-limiting implementation variant was 2.37.

Axes and precipitated heights (in inches) Hit A B C one 3.25 2 4.25 3 4.25 four 3.25 five 4.75 6 four 7 3.25 eight 4.75 9 four ten 3.25 eleven 4.75 12 four 13 3.25 14 4.75 15 four sixteen 3.25 Total deformation 2.37

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

EXAMPLE 6

[0162] According to one non-limiting embodiment of the present invention, a cube-shaped billet with a side of 4.0 inches (101.6 mm) of Ti-6-2-4-2 alloy was subjected to beta annealing at a temperature of 1950 ° F (1066 ° C ) for 1 hour and then cooled in air. Then, heat-controlled all-round forging with a high strain rate was applied to the workpiece according to the embodiments of the present invention, including 6 impacts (2 ABC cycles of all-round forging) at a temperature of 1900 ° C with 30-second pauses between blows. 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 edge (101.6 mm), this plunger speed leads to a minimum strain rate during pressing, which is 0.25 s ^-1 . A sequence of 6 strokes with intermediate pauses was designed to heat the surface of the workpiece with the intersection of the beta transition temperature during comprehensive forging, which in this application can thus be referred to as "comprehensive forging with a high strain rate with a beta transition intersection". This method leads to the grinding of surface structures and minimizing cracking during subsequent forging. Then, the billet was heated to a temperature of 1650 ° F (898.9 ° C), i.e., below the beta transition temperature, and held for 1 hour. Then, a comprehensive forging was applied to the workpiece in accordance with embodiments of the present invention, containing 6 strokes (two ABC forging cycles) with approximately 15-second pauses between shocks. The first three blows (blows in the first ABC all-round forging cycle) were performed to an upset height of 3.5 inches (88.9 mm), and the second 3 blows (blows in the second ABC all-round forging cycle) were performed to an upset height of 3.25 inches (82.55 mm). The billet was heated to a temperature of 1650 ° F and held for 30 minutes between blows with a 3.5-inch (88.9 mm) backing ring and blows with a 3.25-inch (82.55 mm) backing ring. The reduced sediment (i.e., the increased precipitated height) used for the first 3 hits was intended to block cracking, since the reduced sediment destroys the boundary structures that can lead to cracking. Then the billet was reheated to 1500 ° F (815.6 ° C) and held for 1 hour. Then, a comprehensive forging was applied to the workpiece according to embodiments of the present invention using 3 ABC strokes (one forging cycle) with a draft to a height of 3.25 inches (82.55 mm) with 15 second pauses between strokes. Such a sequence with increased precipitation is intended to carry out additional work in non-boundary structures. The plunger speed for all strokes described in Example 6 was 1 inch per second (25.4 mm / s).

[0163] In Example 6, a total strain of 3.01 was given to the blank. A representative micrograph of the central part of the workpiece after heat-controlled all-round forging in Example 6 is shown in FIG. 16 (a). A representative micrograph of the surface area of the workpiece after heat-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 are about 4 microns or less in size, which is an ultrafine microstructure. The microstructure of the central part shown in FIG. 16 (a), shows very fine grains, and it is assumed that, in all likelihood, alpha particles consist of individual alpha grains, and that each alpha grain has a size of about 4 microns or less and is equiaxial in shape.

[0164] It should be understood that the present description presents aspects of the invention consistent with a clear understanding of the present invention. Some aspects that are obvious to those skilled in the art 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 is described in this application, specialists, after considering the above description, will agree that many modifications and changes to 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 claims.

Claims (43)

1. The method of processing billet of titanium alloy, comprising the steps: 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 workpieces, including: forging the workpiece on the press at the forging temperature of the workpiece in the direction of the first axis of the workpiece with a deformation rate sufficient to adiabatically heat the internal area of the workpiece, forging the workpiece on the press at the temperature of the forging of the workpiece in the direction of the second axis of the workpiece with a deformation rate sufficient to adiabatically heat the internal area of the workpiece, forging the workpiece on the press at the temperature of the forging of the workpiece in the direction of the third axis of the workpiece with a deformation rate sufficient for adiabatic heating of the internal area of the workpiece, however, the first axis, the second axis and the third axis are not the same or parallel, and repetition of at least one of the forging of the workpiece on the press to achieve in the workpiece a total true deformation of at least 1.0; however, the forging temperature of the workpiece is in the range of 100 ° F (55.6 ° C) below the temperature of the beta transition of the titanium alloy to a temperature of 700 ° F (388.9 ° C) below the temperature of the beta transition of the titanium alloy, and the strain rate used during press forging is in the range of 0.2 to 0.8 s ^-1 . 2. The method according to p. 1, characterized in that at least one of the forging workpiece on the press is repeated to achieve in the workpiece true deformation in the range from 1.0 to less than 3.5. 3. The method according to p. 1, characterized in that the processing is subjected to a billet of 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 stopping grain elements or beta-stabilizing elements to reduce the release of the alpha phase and the kinetics of its growth. 5. The method according to p. 1, characterized in that the processing is subjected to a billet of titanium alloy selected from alloys including Ti-6Al-2Sn-4Zr-6Mo (UNS R56260), Ti-6Al-2Sn-4Zr-2Mo-0, 08Si (UNS R54620), Ti-4A1-2,5V (UNS R54250), Ti-6Al-7Nb (UNS R56700) and Ti-6Al-6V-2Sn (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 workpiece includes cooling the workpiece to a temperature equal to the forging temperature of the workpiece. 8. The method according to p. 1, characterized in that the beta annealing of the workpiece includes heating the workpiece to the temperature of the beta annealing in the range from the temperature of the beta transition of the titanium alloy to a temperature of 300 ° F (167 ° C) above the temperature of the beta transition of titanium alloy. 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 from 5 minutes to 24 hours. 10. The method according to p. 1, characterized in that before cooling the beta-annealed preform, it further includes plastic deformation of the preform at a temperature in the beta-phase region of the titanium alloy. 11. The method according to p. 10, characterized in that the plastic deformation of the workpiece at a temperature in the beta-phase of the titanium alloy includes at least one of the drawing and forging a draft 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 of 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 the plastic deformation of the workpiece includes forging the draft of the workpiece to achieve the degree of deformation of the draft in the beta-phase region in the range from 0.1 to 0.5. 14. The method according to p. 1, characterized in that it additionally includes in the intervals between successive forgings of the workpiece on the press to ensure the possibility of cooling the adiabatically heated inner region of the workpiece to the forging temperature of the workpiece when heating the outer surface of the workpiece to the workpiece forging temperature. 15. The method according to p. 14, characterized in that the adiabatically heated inner region of the workpiece provides the ability to cool for from 5 to 120 seconds. 16. The method according to p. 14, characterized in that it further includes heating the die for forging used for forging the workpiece on the press to a temperature in the range from the forging temperature of the workpiece to a temperature 100 ° F (55.6 ° C) below the temperature forging billet. 17. The method according to p. 1, characterized in that after achieving a true deformation of at least 1.0, the workpiece has an average grain size of alpha particles in the range of 4 microns or less. 18. The method according to p. 1, characterized in that the titanium alloy is an alloy of Ti-6Al-2Sn-4Zr-2Mo-0.08Si (UNS R54620), and the range of forging temperatures ranges from 1120 ° F (604.4 ° C ) up to 1520 ° F (826.7 ° C). 19. The method according to p. 1, characterized in that the titanium alloy is an alloy of Ti-6Al-2Sn-4Zr-6Mo (UNS R56260), and the range of forging temperatures ranges from 1020 ° F (548.9 ° C) to 1620 ° F (882.2 ° C). 20. The method according to p. 1, characterized in that the titanium alloy is an alloy of Ti-4Al-2.5V (UNS R54250), and the range of forging temperatures is from 1080 ° F (582.2 ° C) to 1680 ° F ( 915.6 ° C). 21. The method according to p. 1, characterized in that the titanium alloy is an alloy of Ti-6Al-6V-2Sn (UNS R56620), and the forging temperature range is from 1035 ° F (527.2 ° C) to 1635 ° F ( 890.6 ° C). 22. The method according to p. 1, characterized in that at the expense of each forging provide adiabatic heating of the inner region of the workpiece on the value from 100 ° F (55.6 ° C) to 300 ° F (166.7 ° C). 23. The method according to p. 1, characterized in that: the titanium alloy is an alloy of Ti-6Al-2Sn-4Zr-2Mo-0.08 Si (UNS R54620), the forging temperature range is from 1120 ° F (604.4 ° C) to 1520 ° F (826.7 ° C), and each forging on the press is carried out with a deformation rate sufficient to adiabatically heat the inner region of the workpiece by an amount from 100 ° F (55.6 ° C) to 300 ° F (166.7 ° C). 24. The method according to p. 23, characterized in that between successive forgings on the press provide the ability to cool the adiabatically heated inner region of the workpiece during a time in the range from 5 to 120 seconds. 25. The method according to p. 1, characterized in that: the titanium alloy is an alloy of Ti-6Al-2Sn-4Zr-6Mo (UNS R56260), the forging temperature range is from 1020 ° F (548.9 ° C) to 1620 ° F (882.2 ° C), and each forging is the press is carried out at a deformation rate sufficient to adiabatically heat the inner region of the preform by a value from 100 ° F (55.6 ° C) to 300 ° F (166.7 ° C). 26. The method according to p. 25, characterized in that between successive forgings on the press provide the ability to cool the adiabatically heated inner region of the workpiece during a time in the range from 5 to 120 seconds. 27. The method according to p. 1, characterized in that: the titanium alloy is an alloy of Ti-4Al-2.5V (UNS R54250), the forging temperature range is from 1080 ° F (582.2 ° C) to 1680 ° F (915.6 ° C), and each forging on the press is carried out with a strain rate sufficient to adiabatically heat the inner region of the workpiece from 100 ° F (55.6 ° C) to 300 ° F (166.7 ° C). 28. The method according to p. 27, characterized in that between successive forgings on the press provide the ability to cool the adiabatically heated inner region of the workpiece during a time in the range from 5 to 120 seconds. 29. The method according to p. 1, characterized in that: the titanium alloy is an alloy of Ti-6Al-6V-2Sn (UNS R56620), the forging temperature range is from 1035 ° F (527.2 ° C) to 1635 ° F (890.6 ° C), and each forging on the press is carried out with a strain rate sufficient to adiabatically heat the inner region of the workpiece from 100 ° F (55.6 ° C) to 300 ° F (166.7 ° C).

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