MX2015004870A

MX2015004870A - Methods for processing titanium alloys.

Info

Publication number: MX2015004870A
Application number: MX2015004870A
Authority: MX
Inventors: John V Mantione; Jean-Philippe Thomas; David J Bryan
Original assignee: Ati Properties Inc
Priority date: 2012-12-14
Filing date: 2013-11-26
Publication date: 2015-07-21
Also published as: BR112015010745A2; RU2637446C2; CN104797723B; RU2017140315A3; NZ707000A; AU2013360096A1; CA2886994A1; KR102001279B1; BR112015010745A8; ES2717651T3; HK1212400A1; MX368287B; PT2931930T; KR20150095613A; UA115157C2; TW201439333A; IL257905B; AU2017203311C1; RU2688109C2; EP2931930B1

Abstract

Methods of refining the grain size of a titanium alloy workpiece include beta annealing the workpiece, cooling the beta annealed workpiece to a temperature below the beta transus temperature of the titanium alloy, and high strain rate multi-axis forging the workpiece. High strain rate multi-axis forging is employed until a total strain of at least 1 is achieved in the titanium alloy workpiece, or until a total strain of at least 1 and up to 3.5 is achieved in the titanium alloy workpiece. The titanium alloy of the workpiece may comprise at least one of grain pinning alloying additions and beta stabilizing content effective to decrease alpha phase precipitation and growth kinetics.

Description

METHODS FOR PROCESSING TITANIUM ALLOYS DECLARATION WITH RESPECT TO A RESEARCH OR DEVELOPMENT WITH FEDERAL SPONSORSHIP The present invention was made with the support of the United States government according to contract number NIST 70NANB7H7038, granted by the National Institute of Standards and Teenology (NIST), Department of Commerce of the United States. The government of the United States may have certain rights over the invention.

ANTECEDENTS OF THE TECHNOLOGY FIELD OF THE TECHNOLOGY The present disclosure relates to methods for processing titanium alloys.

DESCRIPTION OF THE BACKGROUND OF THE TECHNOLOGY The methods to produce titanium and titanium alloys that have a coarse granular microstructure (CG, for their acronyms in English), fine (FG, for its acronym in English), very thin (VFG, for its acronym in English) or ultrafine (UFG, for its acronym in English) involve the use of multiple overheating and stages of forging. The forging stages may include one or more forging stages by upsetting in addition to carrying out the forging in an open die press.

As used herein, when reference is made to the microstructure of titanium alloys: the term "coarse grain" refers to alpha grain sizes of 400 mm to greater than 14 mm; the term "fine grain" refers to grain sizes alphas in the range of 14 mm to greater than 10 mpm · the term "very fine grain" refers to grain sizes alphas of 10 mm to greater than 4.0 qm; and the term "ultra-fine grain" refers to grain sizes of 4.0 mm or less.

Known commercial methods of forging titanium and titanium alloys to produce coarse grain microstructures or fine grains employ deformation rates of 0.03 s1 to 0.10 s1 using various reheating and forging steps.

Known methods for the manufacture of fine grain microstructure, very fine grain or ultra fine grain are subjected to a process of multi-axis forging (MAF) at an ultra-slow deformation speed of 0.001 s1 or slower (see, for example, Salishchev, et al., Materials Science Forum, Vol.584-586, pp. 783-788 (2008)).) The generic MAF process is described in, for example, C. Desrayaud, et. al, Journal of Materials Processing Technology, 172, pp.152-156 (2006).

The key to achieving the refinement of the grain in the MAF process at an ultralow deformation rate is the ability to operate, continuously, in a dynamic recrystallization regime that is a result of the ultra-high deformation velocities used, that is, 0.001 s1 or slower. During dynamic recrystallization, grains nucleate, generate and accumulate dislocations simultaneously. The generation of dislocations within the new nucleated grains continuously reduces the motive force for the growth of grains and the nucleation of the grains is energetically favorable. The MAF process at an ultralow deformation speed uses dynamic recrystallization to continuously recrystallize the grains during the forging process.

Cubes of relatively uniform ultra-fine grain Ti-6-4 alloy (U S R56400) can be produced by the MAF process at an ultra-low deformation rate, but the cumulative time taken to carry out the MAF steps can be excessive in a commercial setting. Additionally, on a conventionally large scale, the commercially available open die press forging equipment may not have the ability to achieve the ultra-high deformation rates required in such modalities and, therefore, a forging equipment may be necessary. measure to carry out the MAF at ultra-high deformation speeds on a production scale.

Accordingly, it would be advantageous to develop a process for producing titanium alloys having coarse, fine, very fine or ultrafine microstructures that do not need multiple reheating, adjust the higher deformation rates, reduce the time needed for processing and / or eliminates the need to resort to customized forging equipment.

COMPENDIUM According to a non-limiting aspect of the present disclosure, a method for refining the grain size of a workpiece comprising a titanium alloy comprises employing beta annealing in the workpiece. After beta annealing, the workpiece is cooled to a temperature below the beta transus temperature of the titanium alloy. The work piece is then forged with multiple axes. The multi-axis forging comprises: forging by press the workpiece at a setting temperature of the workpiece in a temperature range of the workpiece in the direction of a first orthogonal axis of the workpiece with a speed of deformation sufficient to heat, adiabatically, an internal region of the workpiece; forging the workpiece at a forging temperature of the workpiece in the temperature range of the workpiece in the direction of a second orthogonal axis of the workpiece with a deformation speed sufficient to heat, by pressing the workpiece. adiabatic form, the internal region of the work piece; Y press-forming the workpiece at a forging temperature of the workpiece into a setting temperature range of the workpiece in the direction of a third orthogonal axis of the workpiece with a deformation speed sufficient to heat , adiabatically, the internal region of the work piece. Optionally, intermediate to the successive stages of forging by press, the internal region of the work piece heated adiabatically is allowed to cool to a temperature equal to or close to the temperature of forging of the workpiece in the temperature range for forging the workpiece, and an outer surface region of the workpiece is heated to a temperature equal to or close to the setting temperature of the workpiece in the forging range of the workpiece. At least one of the press forging stages is repeated until a total deformation of at least 1.0 is achieved in at least one region of the workpiece. In another non-exhaustive embodiment, at least one of the stages of pressing forging is repeated until a total deformation of at least 1.0 to less than 3.5 is achieved in at least one region of the work piece. In a non-exhaustive mode, a deformation speed used during the Forging by press is in the range of 0.2 s1 to 0.8 s1.

According to another non-exhaustive aspect of the present description, a non-exhaustive modality of a method for refining the grain size of a workpiece comprising a titanium alloy includes employing beta annealing in the workpiece. After beta annealing, the workpiece is cooled to a temperature below the beta transus temperature of the titanium alloy. The workpiece is then forged with multiple axes by a sequence comprising the following stages of forging.

The workpiece is forged by press at a forging temperature of the workpiece in a forging temperature range of the workpiece in the direction of a first orthogonal axis A of the workpiece to a height of the spacer of the workpiece. considerable reduction with a speed of deformation that is sufficient to heat, adiabatically, an internal region of the workpiece. As used herein, a considerable reduction spacer height is a distance equivalent to the final forged dimension desired for each orthogonal axis of the workpiece.

The workpiece is forged by press at the wrought temperature of the workpiece in the wrought temperature range of the workpiece in the direction of a second orthogonal axis B of the workpiece in a first blocking reduction at a first height of blocking reduction spacer. The first blocking reduction is applied to return the workpiece, substantially, the shape prior to the forging of the work piece. While the deformation rate of the first blocking reduction may be sufficient to adiabatically heat an internal region of the work piece, in a non-exhaustive mode, the adiabatic heating during the first block reduction may not occur that the total deformation in which the first blockage reduction was incurred may not be sufficient to significantly heat the work piece adiabatically. The first height of blocking reduction spacer is greater than the height of spacer of considerable reduction.

The workpiece is forged by press at the wrought temperature of the workpiece in the forging temperature range of the workpiece in the direction of a third orthogonal axis C of the workpiece in a second blocking reduction at a second height of blocking reduction spacer. The second lock reduction is applied to return the work piece, substantially, the shape prior to the forging of the work piece. While the deformation rate of the second blocking reduction may be sufficient to adiabatically warm an internal region of the work piece, in a non-restrictive mode, the adiabatic heating during the second blocking reduction may not occur. that the total deformation in which the second blocking reduction was incurred may not be sufficient to heat the workpiece significantly adiabatically. The second height of blocking reduction spacer is greater than the height of spacer of considerable reduction.

The workpiece is forged by press at a forging temperature of the workpiece in a forging temperature range of the workpiece in the direction of the second orthogonal axis B of the workpiece up to the height of the considerable reduction spacer with a deformation speed that is sufficient to heat, adiabatically, an internal region of the workpiece.

The workpiece is forged by press at the forging temperature of the workpiece in the forging temperature range of the workpiece in the direction of the orthogonal third axis C of the workpiece in a first blocking reduction to The first height of blocking reduction spacer. The first blocking reduction is applied to return the work piece, substantially, the shape prior to the forging of the work piece. While the deformation rate of the first blocking reduction may be sufficient to adiabatically heat an internal region of the work piece, in a non-exhaustive mode, the adiabatic heating during the first block reduction may not occur that the total deformation in which the first blocking reduction was incurred may not be sufficient to significantly warm the work piece adiabatically. The first height of spacer Lock reduction is greater than the spacer height of considerable reduction.

The workpiece is forged by press at the forging temperature of the workpiece in the forging temperature range of the workpiece in the direction of the first orthogonal axis A of the workpiece in a second blocking reduction to the second height of blocking reduction spacer. The second lock reduction is applied to return the work piece, substantially, the shape prior to the forging of the work piece. While the deformation rate of the second blocking reduction may be sufficient to adiabatically warm an internal region of the work piece, in a non-restrictive mode, the adiabatic heating during the second blocking reduction may not occur. that the total deformation in which the second blocking reduction was incurred may not be sufficient to heat the workpiece significantly adiabatically. The second height of blocking reduction spacer is greater than the height of spacer of considerable reduction.

The workpiece is forged by press at the forging temperature of the workpiece in the forging temperature range of the workpiece in the direction of the orthogonal third axis C of the workpiece at considerable reduction up to the height of spacer of considerable reduction with a speed of deformation that is sufficient to heat, in an adiabatic manner, an internal region of the work piece.

The workpiece is forged by press at the forging temperature of the workpiece in the forging temperature range of the workpiece in the direction of the first orthogonal axis A of the workpiece in a first blocking reduction to The first height of blocking reduction spacer. The first blocking reduction is applied to return the work piece, substantially, the shape prior to the forging of the work piece. While the deformation rate of the first blocking reduction may be sufficient to adiabatically heat an internal region of the work piece, in a non-exhaustive mode, the adiabatic heating during the first block reduction may not occur that the total deformation that was incurred in the first blocking reduction it may not be enough to heat significantly, in an adiabatic way, the work piece. The first height of blocking reduction spacer is greater than the height of spacer of considerable reduction.

The workpiece is forged by press at the forging temperature of the workpiece in the forging temperature range of the workpiece in the direction of the second orthogonal axis B of the workpiece in a second blocking reduction to the second height of blocking reduction spacer. The second lock reduction is applied to return the work piece, substantially, the shape prior to the forging of the work piece. While the deformation rate of the second blocking reduction may be sufficient to adiabatically heat an internal region of the work piece, in a non-exhaustive mode, adiabatic heating during the second blocking reduction may not occur. that the total deformation in which the second blocking reduction was incurred may not be sufficient to heat the workpiece significantly adiabatically. The second height of the spacer Lock reduction is greater than the spacer height of considerable reduction.

Optionally, the successive intermediate stages of forging by press of the method of the above method, the internal region of the work piece heated adiabatically is allowed to cool to a temperature around the temperature of forging of the workpiece in the range of The workpiece forging temperature, and the outer surface region of the workpiece is heated to a temperature around the forging temperature of the workpiece in the forging range of the workpiece. At least one of the preceding press forging stages of the method embodiment is repeated until a total deformation of at least 1.0 is achieved in at least one region of the workpiece. In a non-exhaustive embodiment of the method, at least one of the stages of press forging is repeated until a total deformation of at least 1.0 and up to less than 3.5 is achieved in at least one region of the work piece. In a non-exhaustive embodiment, a deformation speed used during pressing forging is in the range of 0.2 s1 to 0.8 s1.

BRIEF DESCRIPTION OF THE FIGURES The features and advantages of the apparatuses and methods described herein can be better understood by referring to the appended figures in which: Figure 1 shows a calculated prediction of the volume fraction of the alpha phase equilibrium present in the alloys Ti-6-4, Ti-6-2-4-6 and Ti-6-2-4-2 as a function of the temperature; Figure 2 is a flow diagram that lists the steps of a non-exhaustive mode of a method for processing titanium alloys according to the present disclosure; Figure 3 is a schematic representation of the aspects of a non-exhaustive embodiment of a multi-axis forging method at high speed of deformation using thermal management to process titanium alloys for the refinement of grain sizes, where Figures 2 (a), 2 (c) and 2 (e) represent the non-exhaustive stages of forging by press, and Figures 2 (b), 2 (d) and 2 (f) represent optional non-exhaustive cooling and heating stages according to non-exhaustive aspects of the present description; Figure 4 is a schematic representation of the aspects of a previous technique of a multi-axis forging technique of slow deformation velocity known for its use in refining the size of small-scale samples; Figure 5 is a flow chart that lists the steps of a non-exhaustive mode of a method for processing the titanium alloys according to the present disclosure that includes considerable orthogonal reductions to the desired final dimension of the workpiece and the first and second block reductions; Figure 6 is a table of the temperature-time thermomechanical process for a non-exhaustive embodiment of a method of multi-axis forging of high deformation velocity according to the present disclosure; Figure 7 is a table of the temperature-time thermomechanical process for a non-exhaustive embodiment of a method of multi-axis forging of high deformation velocity in accordance with the present disclosure; Figure 8 is a graph of a thermomechanical temperature-time process for a non-exhaustive embodiment of a full-speed, multi-axis forging method of full beta transus deformation according to the present disclosure; Figure 9 is a schematic representation of the aspects of a non-exhaustive embodiment of a multiple extrusion and extrusion method for the refinement of grain size according to the present disclosure; Figure 10 is a flow chart that lists the steps of a non-exhaustive modality of a method for processing by stressing and multiple extrusion of titanium alloys according to the present disclosure; Figure 11 (a) is a micrograph of the microstructure of a forged and commercially processed Ti-6-2-4-2 alloy; Figure 11 (b) is a micrograph of the microstructure of a Ti-6-2-4-2 alloy processed by the thermally managed high deformation MAF mode described in Example 1 of the present disclosure; Figure 12 (a) is a micrograph depicting the microstructure of a forged and commercially processed Ti-6-2-4-2 alloy; Figure 12 (b) is a micrograph of the microstructure of a Ti-6-2-4-6 alloy processed by the thermally managed high deformation MAF mode described in Example 2 of the present disclosure; Figure 13 is a micrograph of the microstructure of a Ti-6-2-4-6 alloy processed by the thermally managed high deformation MAF mode described in Example 3 of the present disclosure; Figure 14 is a micrograph of the microstructure of a Ti-6-2-4-2 alloy processed by the thermally managed high deformation MAF mode described in Example 4 of the present description that applies an equal deformation in each axis; Figure 15 is a micrograph of the microstructure of a Ti-6-2-4-2 alloy processed by the thermally managed high deformation MAF mode described in Example 5 of the present disclosure, where blocking reductions are used to minimize a protrusion of the work piece that occurs after each considerable reduction; Figure 16 (a) is a micrograph of the central region microstructure of a Ti-6-2-4-2 alloy processed by the high-strain MAF embodiment of the full-length transaminase MAF described in Example 6 of the present description; Y Figure 16 (b) is a micrograph of the microstructure of the surface region of a Ti-6-2-4-2 alloy processed by the thermally managed high-deformation MAF mode utilized full-length beta-transusa MAF described in Example 6 of the present description; The reader will appreciate the preceding details, as well as others, by taking into account the following detailed description of certain non-exhaustive modalities in accordance with the present description.

DETAILED DESCRIPTION OF CERTAIN NO MODALITIES TAXATIVES In the present description of non-exhaustive modalities, apart from the operative examples or when indicated otherwise, all the numbers that express quantities or characteristics must be understood as modified in all cases by the term "around". Accordingly, unless otherwise indicated, any numerical parameter set forth in the following description is an approximation which may vary depending on the desired properties one seeks to obtain by methods according to the present disclosure. At a minimum and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be interpreted in light of the number of significant digits recorded and by the application of common rounding techniques.

In addition, any numerical range mentioned herein is intended to include all subintervals contained therein. For example, a range of "1 to 10" is intended to include all subintervals between (and including) the indicated minimum value of 1 and the indicated maximum value of 10, that is, having a minimum value equal to or greater than 1 and a maximum value equal to or less than 10. Any maximum numerical limitation mentioned herein is intended to include all of the lower numerical limitations encompassed and any minimum numerical limitation described herein is intended to include all of the major numerical limitations encompassed. Accordingly, the Requesters reserve the right to modify the present description, which includes the claims, to expressly list any sub-ranges included in the ranges expressly mentioned herein. It is intended that all such ranges be intrinsically described herein so that the modification to expressly list any of these sub-ranges complies with the requirements of article 112 of title 35 of USC, first subparagraph, and of article 132 (a) of Title 35 of the USC As used herein, the grammatical items "a", "an", "the" and "the" are intended to include "at least one" or "one or more" unless otherwise indicated. Therefore, the articles are used herein to refer to one or more than one (i.e., at least one) of the grammatical objects of the article. By way of example, "a component" means one or more components, and therefore, more than one component is contemplated and may be employed or used in an implementation of the described embodiments.

The present description includes descriptions of various modalities. It should be understood that all the modalities described herein are by way of example, illustrative and not exhaustive. Therefore, the description of the various exemplary modalities, illustrative and non-exhaustive, does not limit the invention. On the contrary, the invention is defined exclusively by the claims, which can be modified to mention any feature described expressly or intrinsically or expressly or intrinsically supported in another form by the present description.

Any patent, publication or other material description, in whole or in part, that is said to be incorporated by reference herein, is incorporated herein, only to the extent that the incorporated material does not conflict with the definitions, statements or other existing descriptive material set forth in the present disclosure. As such, and to the extent necessary, the description, as set forth herein, supersedes any conflicting material incorporated herein by reference. Any material, or part thereof, that is indicated to be incorporated herein by reference, but which conflicts with definitions, statements or other existing descriptive material indicated herein is incorporated only to the extent that no conflicts arise. between the incorporated material and the existing descriptive material.

One aspect of the present disclosure is directed to non-exhaustive embodiments of a multi-axis forging process for titanium alloys which includes the application of high deformation rates during the forging stages to refine the grain size. These method modalities are referred to in the present description as "high-deformation multi-axis forging or" high-velocity-velocity MAF ". as used herein, the terms "reduction" and "impact" refer, interchangeably, to a step of forging by individual press, where a work piece is forged between surfaces of. As used herein, the phrase "height of the spacer" refers to the dimension or thickness of a work piece measured along an orthogonal axis after a reduction along that axis. For example, after a reduction of pressing forging along a particular axis to a spacer height of 4.0 inches, the thickness of the workpiece forged by press measured along the axis will be about 4. , 0 inches. The concept and use of spacer heights are known to those skilled in the field of press forging and do not need to be treated additionally herein.

It was previously determined that for alloys such as the Ti-6AI-4V alloy (ASTM Grade 5; UNS R56400), which can also be referred to as "Ti-6-4" alloy, multi-axis forging can be used. high deformation speed, where the workpiece was forged at least to a total deformation of 3.5 to prepare ultra-fine grain bars. This process is described in the application for US Patent No. 12 / 882,538, filed September 15, 2010, entitled "Processing Routes for Titanium and Titanium Alloys" ("Application Form for Titanium and Titanium Alloys") ("Application 538"), which is incorporates the present in its entirety through this reference. The application of deformation of at least 3.5 may require a significant processing time and complexity, which adds costs and increases the possibility of having unanticipated problems. The present disclosure describes a multi-axis forging high-speed deformation process that can provide ultra-fine grain structures utilizing a total strain in the range of from at least 1.0 to less than 3.5.

The methods, in accordance with the present disclosure, involve the application of multi-axis forging and its derivatives, such as the multiple extrusion and re-extrusion process (MUD) described in Application 538 to titanium alloys exhibiting alpha and kinetic precipitation. of effective growth slower than Ti-6-4 alloy. In particular, the alloy Ti-6AI-2Sn-4Zr-2Mo-0.08Si (UNS R54620) which can also be referred to as "Ti-6-2-4-2" alloy, has effective alpha kinetics more slower than the Ti-6-4 alloy as a result of grain fixing elements such as Si. Likewise, the Ti-6AI-2Sn-4Zr-6Mo alloy (UNS R56260), which can also be referred to as "Ti-6-2-4-6" alloy, has slower effective alphas kinetics than the T-6 alloy -4 as a result of increased beta stabilizing content. It is recognized that, in terms of alloying elements, the growth and precipitation of the alpha phase is a function of the diffusion rate of the alloying element in the titanium-based alloy. It is known that molybdenum has one of the slowest diffusion rates of all additions of titanium alloys. In addition, beta stabilizers, such as molybdenum, decrease the transusium beta (Tp) temperature of the alloy, where low Tp generally results in a slower diffusion of the atoms in the alloy at the process temperature for the alloy. One result of the relatively slow effective growth and precipitation kinetics of the alloys Ti-6-2-4-2 and Ti-6-2-4-6 is that the beta thermal treatment, used before the MAF according to the modalities of the present disclosure produces a fine and stable alpha ribbon size when compared to the effect of said process on the Ti-6-4 alloy. In addition, after the thermal treatment beta and of the cooling, the alloys Ti-6-2-4-2 and Ti-6-2-4-6 have a structure of fine grain beta that limits the kinetics of the alpha growth of the grain.

Effective kinetics of alpha growth can be evaluated by identifying the slowest diffusion species at a temperature immediately below beta transus. This approach has been described theoretically and experimentally verified in the literature (see Semiatin et al., Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science 38 (4), 2007, pp. 910-921). In titanium and titanium alloys, diffusivity information for all possible alloy elements is not readily available; however, literature analyzes such as that presented in Titanium (second edition, 2007), by Lutjering and Williams, generally agree in the following classification for some common alloying elements :.

DMo < DNb < DAl ~ Dv ~ DSn ~ DZr ~ DHf < Dcr ~ DNi ~ Dcr ~ Dco ~ DMn ~ DFe Therefore, alloys such as the Ti-6-2-4-6 alloy and the Ti-6-2-4-2 alloy containing molybdenum, show the desirable slow alpha kinetics that are required to achieve ultrafine grain microstructures at a comparatively lower deformation than Ti-6-4 alloy where kinetics are controlled by aluminum diffusion. In addition, it could reasonably be postulated that tantalum and tungsten belong to the group of slow diffusers.

In addition to the inclusion of slow diffusing elements to reduce the effective kinetics of the alpha phase, reducing the beta transus temperature in alloys controlled by aluminum diffusion will have a similar effect. A reduction of the beta transus temperature of 100 ° C will reduce the diffusivity of aluminum in the beta phase by an order of magnitude to the beta transus temperature. Alpha kinetics in alloys such as alloy ATI 425 (Ti-4AI-2.5V, UNS 54250) and alloy Ti-6-6-2 (Ti-6AI-6V-2SN; UNS 56620) are possibly controlled by aluminum diffusion; however, the lower beta transus temperatures of these alloys relative to the Ti-6AI-4V alloy also result in the slowest effective alpha kinetics. The Ti-6AI-7Nb alloy (UNS R56700), usually a biomedical version of the Ti-6AI-4V alloy can also exhibit slower effective kinetic alpha given the niobium content.

Initially it was expected that alpha + beta alloys other than Ti-6-4 alloy could be processed under conditions similar to those described in Application 538 at temperatures that could result in similar volume fractions of the alpha phase. For example, according to the predictions using PANDAT software, a commercially available computer tool 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 the alloy Ti-6-2-4-2 at 1600 ° F (871.1 ° C) and the alloy Ti-6-2-4-6 at 1200 ° F (648.9 ° C). See, for example, the Figure 1. However, alloys Ti-6-2-4-2 and Ti-6-2-4-6 were severely cracked when processed in the manner in which the Ti-6-4 alloy was processed in Application 538 using temperatures It was predicted that they would produce a similar volume fraction of the alpha phase. Much higher temperatures were required, which resulted in lower equilibrium volume fractions, and / or deformation per cycle significantly reduced to process, successfully, the alloys Ti-6-2-4-2 and Ti-6-2-4-6.

Variations to the high-speed deformation MAF process, including the alpha / beta forging temperatures, the deformation rate, the impact deformation, the waiting time between impacts, the amount and duration of overheating and thermal treatments Intermediates can affect the resulting microstructure and the presence and extent of cracking. Initially, attempts were made to carry out minor total deformations in order to inhibit cracking, without any expectation that they would result in ultra-fine grain structures. However, when it is. examined, samples processed using smaller total deformations showed a significant promise of producing ultra-fine grain structures. This result was totally unexpected.

In certain non-exhaustive embodiments according to the present disclosure, a method for producing ultrafine grain sizes includes the following steps: 1) selecting a titanium alloy that exhibits effective alpha phase growth kinetics slower than the Ti-6- alloy 4; 2) subjecting the titanium alloy to annealing beta to produce a fine and stable alpha ribbon size and 3) high velocity deformation MAF (or a similar derivative process, such as the multiple extrusion and recessing process (MUD) described in Application 538) to a total deformation of at least 1.0 or in other embodiments, to a total deformation of at least 1.0 to less than 3.5. The word "fine" to describe grain and ribbon sizes, as used herein, refers to the smallest grain size and ribbon that can be achieved in non-exhaustive modes to be in the order of 1 mm. The word "stable" is used in the present to denote that multi-axis forging stages do not significantly increase the size of the alpha grain and do not increase the size of the alpha grain to more than about 100%.

The flow chart shown in Figure 2 and the schematic representation in Figure 3 illustrate aspects of a non-exhaustive mode according to the present description of a method (16) for using a high-speed deformation multi-axis slab (MAF). ) to refine the grain size of titanium alloys. Before the multi-axis forging (26), a workpiece of a titanium alloy 24 is subjected to beta annealing (18) and cooled (20). Air cooling is possible with smaller workpieces, such as, for example, 4-inch cubes; however, cooling by water or liquid can also be used. Faster cooling speeds result in finer ribbon sizes and finer alpha grains. Beta annealing (18) comprises heating the workpiece 24 on the transus ion temperature of the titanium alloy of the workpiece 24 and maintaining it for a sufficient time to form the total beta phase in the workpiece 24. Beta annealing (18) is a process known to the expert in the art and, therefore, is not described in detail herein. A non-exhaustive beta-annealing modality may include heating the workpiece 24 to a beta annealing temperature that is around 50 ° F (27.8 ° C) above the transus beta temperature of the titanium alloy and maintaining the part of working 24 in the temperature for about 1 hour.

After the beta annealing (18), the workpiece 24 is cooled (20) to a temperature below the transus temperature of the titanium alloy of the workpiece 24. In a non-exhaustive embodiment of the present description, The workpiece is cooled to room temperature. As used herein, "ambient temperature" refers to the temperature of the environment. For example, in a non-exhaustive commercial production case, "ambient temperature" refers to the temperature of the factory environment. In a non-restrictive mode, cooling (20) may include inactivation. Inactivation includes submerging the workpiece 24 in water, oil or other suitable liquid and is a process understood by a person skilled in metallurgical engineering. In other non-restrictive embodiments, particularly for smaller workpieces, cooling (20) may comprise air cooling. Any method of cooling a titanium alloy workpiece 24 known to one skilled in the art presently or later is within the scope of the present disclosure. In addition, in a specific non-exhaustive mode, cooling (20) comprises cooling directly to a setting temperature of the workpiece in the forging temperature range of the workpiece for multi-axis high-speed forging. deformation.

After cooling the workpiece (20), the workpiece is subjected to multi-axis forging of high deformation speed (26). As understood by those skilled in the art, multi-axis forging ("MAF"), which can also be referred to as "A-B-C" forging, is a form of severe plastic deformation. Forging high-speed multiple axes (26), according to a non-exhaustive embodiment of the present disclosure, includes heating (step 22 in Figure 2) a workpiece 24 comprising a titanium alloy at a forging temperature in a setting temperature range of the workpiece that is within the alpha + beta phase field of the titanium alloy, followed by MAF (26) using a high strain rate. It is apparent that in a mode in which the cooling step (20) comprising cooling to a temperature in the setting temperature range of the work piece the heating step (22) is not necessary.

A high deformation speed is used in the high-speed deformation MAF to heat, adiabatically, an internal region of the work piece. Without However, in non-exhaustive modalities according to the present description, in at least the last cycle of impacts ABC of the MAF of high speed of deformation in the cycle, the temperature of the internal region of the work piece of titanium alloy 24 does not should exceed the transus beta (Tp) temperature of the titanium alloy workpiece. Therefore, in such non-restrictive embodiments the forging temperature of the workpiece for at least the final cycle of impacts ABC, or at least the last impact of the cycle, of the high-speed deformation MAF should be chosen to ensure that during the MAF of high speed of deformation, the temperature of the internal region of the work piece does not equal or exceed the beta transus temperature of the alloy. For example, in a non-exhaustive embodiment according to the present disclosure, the temperature of the internal region of the workpiece does not exceed 20 ° F (11.1 ° C) below the beta transus temperature of the alloy, i.e. , Tp - 20 ° F (Tp -11.1 ° C), during at least the high-speed cycle of final deformation of the ABC impacts in the MAF or during at least the last impact of forging by press when a total deformation of at least 1.0 or in a range of at least 1.0 to less than 3.5, is achieved in at least one region of the workpiece.

In a non-exhaustive embodiment of high-speed deformation MAF according to the present disclosure, a setting temperature of the workpiece comprises a temperature within a range of setting temperature of the workpiece. In a non-restrictive mode, the workpiece forging temperature is 100 ° F (55.6 ° C) below the beta transus temperature (Tp) of the titanium alloy of the workpiece up to 700 ° F (388.9 ° C) below the beta transus temperature of the titanium alloy. In yet another non-exhaustive mode, the workpiece forging temperature is 300 ° F (166.7 ° C) below the beta transus temperature of the titanium alloy to 625 ° F (347 ° C) below the Beta transus temperature of titanium alloy. In a non-exhaustive embodiment, the lower end of a workpiece forging temperature range in the alpha + beta phase field where the damage, such as, for example, the formation of cracks and cuts, does not occur on the surface of the work piece during the impact of forging.

In a non-exhaustive method mode shown in Figure 2 applied to the Ti-6-2-4-2 alloy, which has a Beta Transus temperature (Tp) of about 1820 ° F (996 ° C), the temperature range of workpiece forging can be 1120 ° F (604.4 ° C) to 1720 ° F (937.8 ° C) or in another mode can be 1195 ° F (646, 1 ° C) at 1520 ° F (826.7 ° C). In a non-exhaustive method embodiment shown in Figure 2 applied to the Ti-6-2-4-6 alloy, which has a transus (Tp) temperature of about 1720 ° F (940 ° C), the range of Forging temperature of the workpiece can be 1020 ° F (548.9 ° C) to 1620 ° F (882.2 ° C) or in another mode it can be 1095 ° F (590.6 ° C) to 1420 ° F (771.1 ° C). In yet another non-exhaustive modality, when the modality shown in Figure 2 is applied to the © ATI 425 alloy (UNS R54250), which is also referred to as "TÍ-4AI-2.5V" alloy and having a transus (Tp) temperature 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 in another mode it can be 1155 ° F (623.9 °) C) at 1480 ° F (804.4 ° C). In yet another non-exhaustive embodiment, when the embodiment of the present description of Figure 2 is applied to an alloy Ti-6AI-6V-2Sn (UNS 56620), which is also referred to as an alloy "Ti-6-" 6-2"and that has a transus beta (Tp) temperature of about 1735 ° F (946.1 ° C), the forging temperature range of the workpiece can be 1035 ° F (527.2 ° C) to 1635 ° F (890.6 ° C), or in another mode it can be 1115 ° F (601.7 ° C) at 1435 ° F (779.4 ° C). The present disclosure involves the application of a high-speed, multi-axis forging deformation and its derivatives, such as the MUD method described in Application 538 to titanium alloys having slower effective alpha and kinetic growth precipitation than the Ti alloy. -6-4.

Referring again to Figures 2 and 3, when the titanium alloy workpiece 24 is at the forging temperature of the workpiece, the workpiece 24 is subjected to high deformation speed MAF (26) . In a non-exhaustive embodiment according to the present disclosure, the MAF (26) comprises press-forging (step 28, shown in Figure 3 (a)) the workpiece 24 at the forging temperature of the workpiece in the direction (A) of a first orthogonal axis 30 of the workpiece using a deformation speed that is sufficient to adiabatically heat the workpiece or at least adiabatically heat a region internal part of the workpiece and deforming, in a plastic way, the work piece 24.

High deformation rates and fast spindle speeds are used to heat the internal region of the workpiece in non-exhaustive modes of high-speed deformation MAF according to the present disclosure. In a non-exhaustive embodiment according to the present disclosure, the term "high deformation velocity" refers to a strain rate located in the range of about 0.2 s1 to about 0.8 s1. In a non-exhaustive embodiment according to the present disclosure, the term "high deformation speed" refers to a strain rate located in the range of about 0.2 s1 to about 0.4 s1.

In a non-exhaustive embodiment according to the present disclosure using a high strain rate as defined hereinbefore, an internal region of the titanium alloy workpiece may be heated, adiabatically, to about 200 ° F. (111.1 ° C) on the forging temperature of the workpiece.

In another non-exhaustive mode, during pressing forging, an internal region is heated adiabatically to a temperature in the range of about 100 ° F (55.6 ° C) to about 300 ° F (166 ° C). 7 ° C) on the forging temperature of the workpiece. In yet another non-exhaustive mode, during press-forging, an internal region is adiabatically heated to a temperature in the range of about 150 ° F (83.3 ° C) to about 250 ° F (138 , 9 ° C) on the forging temperature of the workpiece. As mentioned above, in non-exhaustive modalities, no part of the workpiece should be heated above the transus ion temperature of the titanium alloy during the last cycle of the ABC impacts of the high-speed deformation MAF, or during the last impact on an orthogonal axis.

In a non-exhaustive mode, during the forging of the press (28), the work piece 24 is deformed, in a plastic manner, until it is reduced in height or another dimension that is in the range of 20% to 50%, that is to say, the dimension is reduced by a percentage within that range. In another non-exhaustive mode, during the forging of the press (28), the work piece 24 is deformed, in a plastic manner, until reduce in height or another dimension that is in the range of 30% to 40%.

A multi-axis forging process of known ultra-slow deformation velocity (0.001 s1 or slower) is depicted schematically in Figure 4. Generally, one aspect of multi-axis forging is that after each three-stroke cycle (it is say, "three impacts") of the forging apparatus (which may be, for example, an open die forging), the shape and size of the work piece is close to that of the work piece just before the first impact of that cycle of three impacts. For example, after a cubic piece of work 5 inches on each side is, initially, forged with a first "impact" in the direction of the "a" axis, rotated to 90 ° and forged with a second impact in the direction of the orthogonal axis "b", and then rotated to 90 ° and forged with a third impact in the direction of the orthogonal axis "c", the workpiece will resemble the initial cube and will include approximately 5-inch laterals. In other words, although the cycle of three impacts deformed the cube in three stages along the three orthogonal axes of the cube, as a result of the repositioning of the work piece between Individual impacts and the selection of the reduction during each impact, the total result of the three deformations of forging is to return the cube to its approximate original size and shape.

In another non-exhaustive embodiment, in accordance with the present disclosure, a first forging stage with press (28), shown in Figure 2 (a), also referred to herein as the "first impact", may include forging with press the workpiece in a top portion facing downward at a predetermined spacer height while the workpiece is at a temperature in the range of setting temperatures of the workpiece. As used herein, the term "spacer height" refers to the dimension of the workpiece at the completion of a reduction of forging with a particular press. For example, for a spacer height of 5 inches, the work piece is forged in a dimension of about 5 inches. In a specific non-limiting embodiment of the method of the present disclosure, a spacer height is, for example, 5 inches. In another non-exhaustive mode, the height of a spacer is 3.25 inches. Other spacers heights, such as, for example, less than 5 inches, about 4 inches, about 3 inches, more than 5 inches, or 5 inches up to 30 inches are within the scope of the present modes, but should not be construed as limiting the scope of the present description. The heights of spacers are limited only by the capacities of the forging and optionally, as will be seen here, the capabilities of the thermal management system according to non-exhaustive modalities of the present description to keep the work piece at the temperature for forging the work piece. Heights of spacers less than 3 inches are also within the scope of the embodiments described herein, and such relatively small spacers heights are limited only by the desired characteristics of a finished product. The use of spacer heights of about 30 inches, for example, in methods according to the present disclosure, allows the production of cube-shaped titanium alloy shapes with bar size (eg 30 inch side) with a fine grain size, very fine grain size or ultra-fine grain size. The cubic forms with bar size of conventional alloys have been used as pieces of work that is forged in parts of carcasses, disc, ring and for aeronautical or land-based turbines, for example.

The spacers heights which should be employed in various non-exhaustive modes of methods according to the present description can be determined by a person skilled in the art without the need for undue experimentation in considering the present description. The specific spacer heights can be determined by one skilled in the art without undue experimentation. The heights of specific spacers depend on the ability of a specific alloy to crack during forging. Alloys that have a higher susceptibility to cracking will require heights of larger spacers, that is, less impact deformation to prevent cracking. The adiabatic heating limit should also be considered when choosing a spacer height because, at least in the last cycle of impacts, the temperature of the workpiece should not exceed the Tp of the alloy. In addition, the capacity limit of the forging press needs to be considered when a spacer height is selected. For example, during the pressing of a 4-inch cubic workpiece side, the cross-sectional area increases during the pressing stage. As such, it increases the total load that is required to prevent the workpiece from deforming at the rate of deformation. The load can not increase beyond the capabilities of the press to forge. In addition, the geometry of the workpiece needs to be considered when selecting spacers heights. Large deformations can result in a protrusion in the workpiece. A very large reduction can result in a relative flattening of the work piece, so that the next impact of forging in the direction of a different orthogonal axis can bend the workpiece.

In certain non-exhaustive modalities, the heights of spacers used for each impact on the orthogonal axis are equivalent. In other determined non-exhaustive modes, the heights of spacers used for each impact on the orthogonal axis are not equivalent. The non-restrictive modalities of high-speed deformation MAF using non-equivalent spacer heights for each orthogonal axis are presented below.

After forging with press (28) the workpiece 24 in the direction of the first orthogonal axis 30, that is, in the direction A shown in Figure 2 (a), a non-exhaustive mode of a method according to the present description further comprises, optionally, a step in which it is allowed (step 32) that the temperature of the internal region adiabatically heated (not shown) of the work piece be cooled to a temperature equal to or close to the temperature of forging of the workpiece in the forging temperature range of the workpiece, which is shown in Figure 3 (b). In several non-exhaustive modalities, the cooling times of the internal region, or "waiting" times, can vary, for example, from 5 seconds to 120 seconds, from 10 seconds to 60 seconds or from 5 seconds to 5 minutes. In several non-exhaustive embodiments according to the present disclosure, an "internally adiabatically heated region" of a workpiece, as used herein, refers to a region extending outward from a center of the workpiece. workpiece 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 work piece. An expert in The technician will recognize that the time required to cool the internal region of a workpiece to a temperature equal to or close to the workpiece forging temperature will depend on the size, shape and composition of the workpiece. , as well as the environmental conditions surrounding the work piece 24.

During the cooling period of the inner region, an aspect of a thermal management system 33 according to certain non-exhaustive embodiments described herein optionally comprises heating (step 34) an outer surface region 36 of the work piece 24 a a temperature equal to or close to the setting temperature of the workpiece. In this way, the temperature of the workpiece 24 is in a uniform or nearly uniform and substantially isothermal condition at or near the setting temperature of the workpiece before each high-speed deformation MAF impact. It is recognized that it is within the scope of the present disclosure to heat (34), optionally, the outer surface region 36 of the workpiece 24 after each heating of the A axis, after each impact on the B axis and / or after each impact on the C axis. In modalities not In this case, the external surface of the workpiece is optionally heated (34) after each cycle of impacts A-B-C. In still other non-exhaustive modalities, the external surface region optionally heats up after any impact or cycle of impacts, as long as the overall temperature of the workpiece is kept within the range of the forging temperature of the workpiece during the forging process. The times a workpiece should be heated to maintain a temperature of the workpiece 24 in a uniform or nearly uniform and substantially isothermal condition at or near a workpiece forging temperature before each impact. High deformation speed may depend on the size of the work piece, and this may be determined by a person skilled in the art without undue experimentation. In various non-exhaustive embodiments according to the present disclosure, an "outer surface region" of a workpiece, as used herein, refers to a region extending inward from an external surface of the workpiece. of work 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 work piece. It is recognized that at any time the intermediate In non-restrictive embodiments, an external surface region 36 of the work piece 24 can be heated (34) by using one or more surface heating mechanisms 38 of the thermal management system 33. Examples of possible surface heating mechanisms for the successive press forging steps, the entire workpiece can be placed in an oven or otherwise heated to a temperature with the setting temperature range of the workpiece.

In certain non-exhaustive embodiments, as an optional feature, between each of the impacts of forging A, B and C, the thermal management system 33 is used to heat the outer surface region 36 of the workpiece, and the region The adiabatically heated inner is allowed to cool for a cooling time of the inner region to cause the temperature to return to the workpiece at a substantially uniform temperature equal to or close to the setting temperature of the workpiece. In other specific non-exhaustive modalities of According to the present description, as an optional feature, between each of the impacts of forging A, B and C, the thermal management system 33 is used to heat the outer surface region 36 of the workpiece, and the region The adiabatically heated inner part is allowed to cool for a cooling time of the inner region so that the temperature of the workpiece returns to a substantially uniform temperature within the range of temperature of the workpiece forging. The non-exhaustive modalities of a method according to the present disclosure utilizing (1) a thermal management system 33 for heating the outer surface region of the workpiece to a temperature within the range of temperature of forging of the workpiece. work and (2) a period during which the internal region adiabatically heated is cooled to a temperature within the range of temperature of forging of the workpiece can be referred to herein as "thermally managed, multi-axis forging with high deformation speed ". 38 and includes, but not limited to, flame heaters adapted for heating to flame; induction heaters adapted for induction heating; and radiant heaters adapted for radiant heating of the external surface of the workpiece 24. Other mechanisms and techniques for heating an outer surface region of the workpiece will be apparent to those skilled in the art upon consideration of the present disclosure, and such mechanisms and techniques are within the scope of the present description. A non-exhaustive embodiment of a heating mechanism of the external surface region 38 may comprise a box oven (not shown). A box furnace with several heating mechanisms can be configured to heat the region of the external surface of the work piece using one or more flame heating mechanisms, radiant heating mechanisms, induction heating mechanisms and any other mechanism of heating. suitable heating known now or later by a person skilled in the art.

In another non-exhaustive embodiment, the temperature of the external surface region 36 of the workpiece 24 is optionally heated (34) and maintained at a temperature equal to or close to the setting temperature of the workpiece and within the range of the forging temperature of the work piece using one or more die heaters 40 of a thermal management system 33. The heaters of Die 40 can be used to maintain the dies 42 or the press and die forging surfaces 44 of the dies at a temperature equal to or close to that of the workpiece forging or at temperatures within the range of the forging temperature of the die. Workpiece. In a non-restrictive modality, the dies 42 of the thermal management system are heated to a temperature within a range that includes the temperature of the workpiece forging up to 100 ° F (55.6 ° C) below the workpiece forging temperature of work. The die heaters 40 can heat the dies 42 or the die surface with die press 44 by any suitable heating mechanism known now or later by a person skilled in the art, including, but not limited to, heating mechanisms to flame, radiant heating mechanisms, conduction heating mechanisms and / or induction heating mechanisms. In a non-exhaustive embodiment, a die heater 40 may be a component of a box furnace (not shown). While the thermal management system 33 is not shown in its place and being used during the cooling stages (32), (52), (60) or the multi-axis forging process (26) shown in Figures 2 ( b), (d) and (f), it will be recognized that the thermal management system 33 may or may not be in place during the stages of press forging (28), (46), (56) described in Figures 2 (a), (c) and (e) .

As shown in Figure 3 (c), one aspect of a non-exhaustive embodiment of a multi-axis forging method (26) in accordance with the present disclosure comprises forging with press (step 46) the work piece 24 a a forging temperature of the workpiece in a setting temperature range of the workpiece in the direction (B) of a second orthogonal axis 48 of the workpiece 24 using a deformation speed that is sufficient to heat the adiabatic form the workpiece 24, or at least an internal region of the workpiece 24, and deform the workpiece in a plastic manner 24. In a non-exhaustive mode, during the forging with press (46), the workpiece Work 24 is deformed to a plastic deformation of a 20% to 50% reduction in height or another dimension. In another non-exhaustive mode, during the forging with press (46), the work piece 24 is deformed in a plastic manner until a plastic deformation of a reduction of 30% to 40% in height or another dimension.

In a non-exhaustive mode, the work piece 24 can be forging with press (46) in the direction of the second orthogonal axis 48 to the same height of spacer used in the first forging stage with press (28). In another non-restrictive embodiment, the work piece 24 can be forged with a press in the direction of the second orthogonal axis 48 at a different height of spacer than that used in the first stage of forging with press (28). In another non-exhaustive embodiment, the internal region (not shown) of the work piece 24 is adiabatically heated during the pressing forging stage (46) at the same temperature as that of the first pressing forging stage. In other non-exhaustive embodiments, the high deformation rates used for pressing forging (46) are in the same ranges of deformation velocities as described for the first press forging step (28).

In a non-restrictive embodiment, as illustrated in Figures 2 (b) and (d), the workpiece 24 can be rotated (50) between successive press-forging stages (e.g., (28), (46) ), (56)) to present an orthogonal axis different from the forging surfaces. This rotation can be called rotation "A-B-C". It is understood that when using different forging configurations, it is possible to rotate the head in the forging instead of rotating the work piece 24, or a forging can be equipped with multi-axis heads so that the rotation of the workpiece or the forging is not required. Obviously, the important aspect is the relative change in position of the workpiece and head that is being used, and rotating (50) the workpiece 24 may be unnecessary or optional. In the most current industrial equipment configurations, however, it will be necessary to rotate (50) the workpiece to a different orthogonal axis in the middle of press forging stages to complete the multi-axis forging process (26).

In non-restrictive embodiments in which rotation ABC (50) is required, the workpiece 24 can be rotated manually by a forging operator or by an automatic rotation system (not shown) to provide rotation ABC (50 ). An automatic A-B-C rotation system may include, but is not limited to, free style swing clamp-style manipulator or the like to allow a forging mode of multiple axes of high velocity deformation managed thermally non-exhaustive described herein.

After forging with press (46) the workpiece 24 in the direction of the second orthogonal axis 48, that is, in the direction B, as shown in Figure 3 (d), the process (20) further comprises, optionally, allowing (step 52) that an internal region adiabatically heated (not shown) of the workpiece be cooled to a temperature equal to or close to the forging temperature of the workpiece. work, which is shown in Figure 3 (d). In certain non-exhaustive modalities, the cooling times of the internal region, or waiting times, can vary, for example, from 5 seconds to 120 seconds, or from 10 seconds to 60 seconds or from 5 seconds to 5 minutes. An expert in the art will recognize that the minimum cooling times depend on the size, shape and composition of the work piece 24, as well as on the characteristics of the environment surrounding the work piece.

During the optional cooling period of the internal region, an optional aspect of a thermal management system 33 according to certain non-exhaustive modalities described herein optionally comprise heating (step 54) an outer surface region 36 of the workpiece 24 to a temperature in the range of the workpiece forging temperature equal to or close to the workpiece forging temperature. of work.

In this way, the temperature of the workpiece 24 is maintained in a uniform or nearly uniform and substantially isothermal condition at or near the forging temperature of the workpiece before each impact of high velocity deformation MAF. In non-restrictive embodiments, when the thermal management system 33 is used to heat the outer surface region 36, as well as when the adiabatically heated internal region is allowed to cool during a cooling time in the specific internal region, the The temperature of the workpiece returns to a substantially uniform temperature equal to or close to the setting temperature of the workpiece between each impact of forging ABC. In other non-exhaustive embodiments according to the present description, when the thermal management system is used 33 to heat the outer surface region 36, as well as when the internally adiabatically heated region is allowed to cool during a cooling time in the specific internal region, the temperature of the workpiece returns to a substantially uniform temperature within the range of the setting temperature of the workpiece before each high-speed deformation MAF impact.

In a non-restrictive embodiment, an external surface region 36 of the work piece 24 can be heated (54) using one or more external surface heating mechanisms 38 of the thermal management system 33. Examples of the heating mechanisms 38 possible may include, but not limited to, flame heaters adapted for heating to flame; induction heaters adapted for induction heating; and / or radiant heaters adapted for the radiant heating of the workpiece 24. A non-exhaustive mode of a surface heating mechanism 38 may comprise a box furnace (not shown). Other mechanisms and techniques for heating an external surface of the workpiece will be apparent to those skilled in the art upon consideration of the present disclosure, and such mechanisms and techniques are within the scope of the present disclosure. You can configure a box oven with several mechanisms of heating to heat the external surface of the work piece, and such heating mechanisms may comprise one or more flame heating mechanisms, radiant heating mechanisms, induction heating mechanisms and / or any other heating mechanism known now or more forward by a person skilled in the art.

In another non-exhaustive embodiment, the temperature of the external surface region 36 of the workpiece 24 can be heated (54) and maintained at a temperature equal to or close to the setting temperature of the workpiece and within the range of the forging temperature of the work piece using one or more die heaters 40 of a thermal management system 33. The die heaters 40 can be used to hold the dies 42 or the forging surfaces with die press 44 of the dies at a temperature equal to or close to that of the forging of the workpiece or to temperatures within the range of the forging temperature of the workpiece. The die heaters can heat the dies or the forging surfaces with die press 44 by any suitable heating mechanism known now or later by a person skilled in the art, including, but not limited to, flame heating mechanisms, radiant heating mechanisms, conduction heating mechanisms and / or induction heating mechanisms. In a non-exhaustive embodiment, a die heater 40 may be a component of a box furnace (not shown). While the thermal management system 33 is shown in place and being used during the equilibrium and cooling stages (32), (52), (60) of the multi-axis forging process (26) shown in the Figures 2 (b), (d) and (f), it is recognized that the thermal management system 33 may or may not be in place during the stages of forging with press (28), (46), (56) described in Figures 2 (a), (c) and (e).

As shown in Figure 3 (e), one aspect of a multi-axis forging mode (26) according to the present disclosure comprises press forging (step 56) the workpiece 24 at a forging temperature of the workpiece in a range of setting temperature of the workpiece in the direction (C) of a third orthogonal axis 58 of the workpiece 24 using a deformation speed and head speed which are sufficient to adiabatically heat the workpiece 24, or at least adiabaticly heat an internal region of the workpiece, and plasticly deform the workpiece 24. In a non-exhaustive mode, the workpiece 24 it is deformed during the forging by press (56) to a plastic deformation of a reduction of 20% to 50% in height or another dimension. In another non-exhaustive mode, during the forging with press (56) the work piece is deformed in a plastic manner until a plastic deformation of a reduction of 30% to 40% in height or another dimension. In a non-restrictive embodiment, the work piece 24 can be forged with press (56) in the direction of the third orthogonal axis 58 at the same spacer height in the first stage of press forging (28) and / or the second stage of forging (46). In another non-exhaustive mode, the work piece 24 can be forged with a press in the direction of the third orthogonal axis 58 at a different height of spacer than that used in the first stage of forging with press (28). In another non-exhaustive mode according to the description, the internal region (not shown) of the work piece 24 is heated adiabatically during the step of pressing forging (56) at the same temperature as that of the first step of forging with press (28). In other non-restrictive embodiments, the high deformation rates used for the press forging (56) are in the same ranges of deformation velocities as described for the first stage of press forging (28).

In a non-restrictive embodiment, as shown by the arrow 50 in Figures 3 (b), 3 (d) and 3 (e), the workpiece 24 can be rotated (50) to a different orthogonal axis between the steps successive forging with press (eg, 46, 56). As described above, this rotation can be referred to as rotation A-B-C. It is understood that by using different forging configurations, it is possible to rotate the head in the forging instead of rotating the workpiece 24, or a forging can be equipped with multi-axis heads so that rotation of the workpiece is not required. work or forging. Therefore, rotating the workpiece 24 can be an unnecessary or optional step. In the most current industrial configurations, however, it will be necessary to rotate the workpiece to a different orthogonal axis between stages of forging with press to complete the process of multi-axis forging. (26) After forging with press 56 the workpiece 24 in the direction of the third orthogonal axis 58, that is, in the direction C, as shown in Figure 3 (e), the process 20 further comprises, optionally, allowing (step 60) that an internal region adiabatically heated (not shown) of the workpiece be cooled to a temperature equal to or close to the setting temperature of the workpiece, which is indicated in Figure 3 (f). Cooling times of the internal region may vary, for example, from 5 seconds to 120 seconds, from 10 seconds to 60 seconds, or from 5 seconds to 5 minutes, and one skilled in the art recognizes that cooling times depend on the size, shape and composition of the work piece 24, as well as the characteristics of the environment surrounding the work piece.

During the optional cooling period, an optional aspect of a thermal management system 33 according to non-exhaustive embodiments described herein comprises heating (step 62) an outer surface region 36 of the work piece 24 to an equal temperature or close to the temperature of the workpiece forging. In this way, the temperature of the work piece 24 is maintained in a uniform or nearly uniform and substantially isothermal condition at or near the forging temperature of the workpiece before each impact of high-speed deformation MAF. In non-restrictive modalities, by using the thermal management system 33 to heat the outer surface region 36, as well as when the internally adiabatically heated region is allowed to cool during a cooling time in the specific internal region, the temperature of the workpiece returns to a substantially uniform temperature equal to or close to the forging temperature of the workpiece between each impact of forging ABC. In other non-restrictive embodiments according to the present disclosure, by using the thermal management system 33 to heat the outer surface region 36, as well as when the internally adiabatically heated region is allowed to cool during a cooling time in the specific internal region, the temperature of the workpiece returns to a substantially isothermal condition within the range of the forging temperature of the workpiece between successive shaping impacts ABC.

In a non-restrictive embodiment, an external surface region 36 of the workpiece 24 can be heated (62) using one or more external surface heating mechanisms 38 of the thermal management system 33. Examples of the heating mechanisms 38 possible may include, but are not limited to, flame heaters for heating to flame; induction heaters for induction heating; and / or radiant heaters for the radiant heating of the workpiece 24. Other mechanisms and techniques for heating an external surface of the workpiece will be apparent to those skilled in the art upon consideration of the present disclosure, and such mechanisms and techniques are they are within the scope of the present description. A non-exhaustive embodiment of a surface heating mechanism 38 may comprise a box oven (not shown). A box furnace with several heating mechanisms can be configured to heat the external surface of the work piece using one or more flame heating mechanisms, radiant heating mechanisms and / or any other suitable heating mechanism known now or later by a person skilled in the art.

In another non-exhaustive embodiment, the temperature of the external surface region 36 of the workpiece 24 can be heated (62) and maintained at a temperature equal to or close to the setting temperature of the workpiece and within the range of the forging temperature of the work piece using one or more die heaters 40 of a thermal management system 33. The die heaters 40 can be used to hold the dies 42 or the forging surfaces with die press 44 of the dies at a temperature equal to or close to that of the forging of the workpiece or to temperatures within the range of forging of the workpiece. In a non-limiting embodiment, the dies 42 of the thermal management system are heated to a temperature within a range that includes the setting temperature of the workpiece at 100 ° F (55.6 ° C) below the temperature for forging the work piece. The die heaters can heat the dies or the forging surface with press and die 44 by any suitable heating mechanism known now or later by a person skilled in the art, including, but not limited to, flame heating mechanisms. , radiant heating mechanisms, driving heating mechanisms and / or induction heating mechanisms. In a non-exhaustive embodiment, a die heater 40 may be a component of a box furnace (not shown). While the thermal management system 33 is not shown in its place and being used during the equilibrium stages (32), (52), (60) or the multi-axis forging process shown in Figures 2 (b), (d) and (f), it will be recognized that the thermal management system 33 may or may not be in place during the stages of forging with press 28, 46, 56 described in Figures 2 (a), (c) and ( and).

One aspect of the present disclosure includes a non-exhaustive embodiment wherein one or more stages of press forging together with the three orthogonal axes of a workpiece are repeated until a total deformation of at least 1.0 is achieved in the workpiece. job. The total deformation is the total rectilinear tension. The phrase "rectilinear tension" is also known by a person skilled in the art as "logarithmic tension" or "effective tension". With reference to Figure 2, this is exemplified in step (g), that is, repeating (step 64) one or more of the stages of forging with press (28), (46), (56) until a deformation is achieved total of at least 1.0, or in the range of at least 1.0 to less than 3.5 on the work piece. It is further recognized that after the desired deformation is achieved in any of the forging stages with press (28) or (46) or (56) and that a forging with additional press is not necessary, and the optional balance stages are not necessary (ie, allow the inner region of the workpiece to cool to a temperature equal to or close to the temperature of the workpiece forging (32) or (52) or (60) and to heat the outer surface of the workpiece (34) or (54) or (62) at a temperature equal to or close to the temperature of the forging of the workpiece), the workpiece can be simply cooled to room temperature, in a not exhaustive, by inactivation in a liquid, or in another non-exhaustive mode, by cooling with air or any faster rate of cooling.

It will be understood that in a non-exhaustive embodiment, the total deformation is the total deformation in the entire work piece after the forging of multiple axes, as described herein. In non-restrictive embodiments according to the present disclosure, the total deformation may comprise equal deformations in each orthogonal axis, or deformation Total can comprise erent deformations in one or more orthogonal axes.

According to a non-exhaustive modality, after beta annealing, a work piece can be forged with multiple axes at two erent temperatures in the field of the alpha-beta phase. For example, with reference to Figure 3, repeating step (64) of Figure 2 may include repeating one or more steps (a) - (optional b), (c) - (optional d), and (e) - (optional f) at a first temperature in the alpha-beta phase field until a certain deformation is achieved, and then repeat one or more steps (a) - (optional b), (c) - (optional d), and (e) - (optional f) at a second temperature in the alpha-beta phase field until after a final press forging stage (a), (b), or (c) (ie, ( 28), (46), (56)) achieve a total deformation of at least 1.0 or in the range of at least 1.0 to less than 3.5 in the workpiece. In a non-exhaustive mode, the second temperature in the alpha-beta phase field is smaller than the first temperature in the alpha-beta phase field. It is recognized that carrying out the method to repeat one or more steps (a) - (optional b), (c) - (optional d), and (e) - (optional f) in more than two temperatures of forging with press MAF is within the scope of the present description as long as the temperatures are concentrated within the range of temperature of forging. It is also recognized that, in a non-exhaustive mode, the second temperature in the alpha-beta phase field is greater than the first temperature in the alpha-beta phase field.

In another non-exhaustive embodiment according to the present disclosure, different reductions are used for the impact of the A-axis, the impact of the B-axis and the impact of the C-axis to provide equal deformation in all directions. Applying high-speed deformation MAF to exert equal warpage in all directions results in less cracking, and an equiaxed algrain structure for the work piece. For example, unequal deformation can be exerted on a cubic workpiece by starting with a 4-inch cube that is forged on the A axis at a height of 3.0 inches. This reduction in axis A causes the workpiece to swell along the B axis and the C axis. If a second reduction in the direction of the B axis reduces the axis dimension B at 3.0 inches, more deformation is exerted on the work piece on the B axis than on the A axis.

Thus, a further impact in the direction of the C axis to reduce the C axis to 3.0 inches would exert more deformation on the workpiece on the C axis than on the A axis or the B axis. As another example, to exert a equalized deformation in all orthogonal directions, a cubic workpiece ("impact") is forged on axis A at a height of 3.0 inches, rotated 90 degrees and impact on axis B at a height of 3, 5 inches, and then rotate 90 degrees and hit the C axis at a height of 4.0 inches. This last sequence will result in a cube with sides of approximately 4 inches and even deformation equaled in each orthogonal sense of the cube. A general equation for calculating the reduction in each orthogonal axis of a cubic workpiece during the high deformation velocity MAF in Equation 1.

Equation 1: deformation = -In (height of spacer / starting height) A general equation is provided to calculate the total deformation in Equation 2: Equation 2: total deformation = "-In (height of spacer / start height) Different reductions can be made by using spacers in the forging apparatus that provide different heights of spacers, or by any alternative means known to the person skilled in the art.

In a non-exhaustive embodiment according to the present disclosure, now referring to Figure 5, and considering Figure 3, a process (70) for the production of ultra-fine grain titanium alloy includes: subjecting to beta annealing (71) a titanium alloy workpiece; cooling (72) the workpiece subjected to beta annealing 24 to a temperature below the beta transus temperature of the titanium alloy of the workpiece; heating (73) the workpiece 24 to a workpiece forging temperature within a temperature range of the workpiece that falls within the al+ beta e field of the titanium alloy of the titanium of the work piece; and an MAF of high deformation velocity (74) of the workpiece, where the high deformation velocity MAF (74) includes the press forging reductions to the orthogonal axes of the workpiece at different spacer heights. In a non-restrictive multi-axis forging mode (74) according to the present disclosure, the workpiece 24 is forged by press (75) on the first orthogonal axis (axis A) at a considerable reduction spacer height. The phrase "forging with press ... to a height of spacer of considerable reduction", as used herein, refers to the forging with press of the workpiece along an axis orthogonal to the desired final dimension of the workpiece together with the specific orthogonal axis. Therefore, the term "considerable reduction spacer height" is defined as the height of the spacer used to obtain the final dimension of the workpiece along with each orthogonal axis. All stages of press forging for the spacer height of considerable reduction should occur using a sufficient deformation rate to adiabatically warm an internal region of the workpiece After forging with press (75) the workpiece 24 in the direction of the first axis A orthogonal to a considerable reduction spacer height, as shown in Figure 3 (a), the process (70) optionally further comprises allowing (step 76, indicated in Figure 3 (b)) that an internal region adiabatically heated (not shown) of the workpiece be cooled to a temperature equal to or close to the setting temperature of the workpiece. Cooling times of the internal region may vary, for example, from 5 seconds to 120 seconds, from 10 seconds to 60 seconds, or from 5 seconds to 5 minutes, and a person skilled in the art will recognize that cooling times will depend of the size, shape and composition of the work piece, as well as the characteristics of the environment surrounding the work piece.

During the optional cooling time period of the inner region, an aspect of a thermal management system 33 according to non-exhaustive embodiments described herein may comprise heating (step 77) an outer surface region 36 of the workpiece 24 at a temperature equal to or close to the forging temperature of the workpiece. In this way, the temperature of the Workpiece 24 is maintained in a uniform or nearly uniform and substantially isothermal condition at or near the workpiece forging temperature before each impact of high-speed deformation MAF. In certain non-restrictive embodiments, by using the thermal management system 33 to heat the outer surface region 36, as well as when the adiabatically heated internal region is allowed to cool during a cooling time in the specific internal region, the The temperature of the workpiece returns to a substantially uniform temperature equal to or close to the setting temperature of the intermediate workpiece to each of the forging impacts A, B and C. In other non-exhaustive embodiments according to this description, by using the thermal management system 33 to heat the outer surface region 36, as well as when the adiabatic heated internal region is allowed to cool during a cooling time in the specific internal region, the temperature of the piece working temperature returns to a substantially uniform temperature within the range of the forging temperature of the work piece between each impact of forging A, B and C.

In a non-restrictive embodiment, an outer surface region 36 of the workpiece 24 can be heated using one or more external surface heating mechanisms 38 of the thermal management system 33. The possible examples of the heating mechanisms of the external surface 38 include, but are not limited to, flame heaters adapted for heating to flame; induction heaters adapted for induction heating; and radiant heaters adapted for radiant heating of the workpiece 24. Other mechanisms and techniques for heating an outer surface region of the workpiece will be apparent to those skilled in the art upon consideration of the present disclosure, and such mechanisms and techniques. they are within the scope of the present description. A non-exhaustive embodiment of a heating mechanism of the external surface region 38 may comprise a box oven (not shown). A box furnace with several heating mechanisms can be configured to heat the region of the external surface of the work piece using, for example, one or more flame heating mechanisms, radiant heating mechanisms and / or any other heating mechanism. adequate heating known now or later by a person skilled in the art.

In another non-exhaustive mode, the temperature of the outer surface region 36 of the workpiece 24 can be heated (34) and maintained at a temperature equal to or close to the setting temperature of the workpiece and within the range of the workpiece setting temperature using one or more die heaters 40 of a thermal management system 33. The die heaters 40 can be used to hold the dies 42 or the die-pressing forging surfaces 44 of the dies at a temperature equal to or close to that of the die forging. workpiece or at temperatures within the range of the workpiece's forging temperature. In a non-restrictive modality, the dies 42 of the thermal management system are heated to a temperature within a range that includes the temperature of the workpiece forging up to 100 ° F (55.6 ° C) below the workpiece forging temperature of work. The die heaters 40 can heat the dies 42 or the die surface with die press 44 by any known suitable heating mechanism now or later by a person skilled in the art, including, but not limited to, flame heating mechanisms, radiant heating mechanisms, conduction heating mechanisms and / or induction heating mechanisms. In a non-exhaustive embodiment, a die heater 40 may be a component of a box furnace (not shown). While the thermal management system 33 is shown in its place and being used during the cooling stages of the multi-axis forging process, it is recognized that the thermal management system 33 may be in place or not during the stages of Forging with press.

In a non-exhaustive mode, after pressing forging at a considerable reduction spacer height (75) on axis A (see Figure 3), which is also referred to herein as "A" reduction, and after the optional steps of allowing (76) and heating (77), if applied, subsequent press forgings to block spacer heights, which may include optional heating and cooling stages, are applied on axes B and C for "fix" the piece of work. The phrase "forging with a press ... height of blocking reduction spacer", hereinafter referred to otherwise as forging with press at a first height of blocking reduction spacer ((78), (87), (96)) and press-forming a second blocking reduction spacer ((81), (90), (99)), it defines as a step of forging with a press that is used to reduce or "fix" the protrusion occurring near the center of any face after the forging with a press at a height of spacer of considerable reduction. The protrusion at or near the center of any face results in a triaxial stress state that is introduced into the faces, which could result in cracking of the workpiece. The steps of pressing forging at a first height of reduction spacer and forging with press to a second height of blocking reduction spacer, also referred to herein as a first block reduction, second block reduction or simply block reductions are they use to deform the faces with protuberances, so that the faces of the work piece are flat or substantially flat before the next pressing forging at a height of considerable reduction spacer next to an orthogonal axis. Blocking reductions involve forging with a press at a spacer height that is greater than the height of the spacer used at each stage of the forging with a press spacer height of considerable reduction. While the rate of deformation of all the first and second blocking reductions described herein may be sufficient to adiabatically heat an internal region of the work piece, in a non-exhaustive mode, the adiabatic heating during the first and the second blocking reduction may not occur since the total deformation incurred in the first and in the second blocking reduction may not be sufficient to significantly heat, adiabatically, the workpiece. Since block reductions are made at heights of spacers that are greater than those used in press forging at a considerable reduction spacer height, the deformation added to the workpiece in a blockage reduction may not be sufficient to adiabatically heating an internal region of the work piece. As will be seen, the incorporation of the first and second blocking reduction in a high-speed deformation MAF process, in a non-restrictive mode, results in a forging sequence of at least one cycle consisting of: ABCBCAC , where A, B and C comprise the forging with press at the height of spacer of considerable reduction, and where B, C, C and A comprise the forging with press in the first and second height of blocking reduction spacer; or in another non-exhaustive mode at least one cycle consisting of: A-B-C-B-C-A-C-A-B, where A, B and C comprise the forging with press at the height of considerable reduction spacer, and where B, C, C, A, A and B comprise the forging with press in the first and second height of blocking reduction spacer.

With reference again to Figures 3 and 5, in a non-exhaustive mode, after the step of forging by press to a considerable reduction of the height of spacer (75) in the first orthogonal axis (a reduction A) and, if applied , after the optional steps of permitting (76) and heating (77), as described above, the work piece is forged by press (78) on the B axis at a first spacer height of the blocking reduction. While the deformation rate of the first blocking reduction may be sufficient to adiabatically heat an internal region of the work piece, in a non-exhaustive mode, adiabatic heating during the first blocking reduction may not occur. that the deformation in which the first blocking reduction is incurred may not be sufficient to warm, adiabatically, significantly the piece of work. Optionally, the adiabatic heated inner region of the work piece is allowed to cool to a temperature equal to or close to the workpiece forging temperature, while the region on the external surface of the workpiece. it is heated (80) to a temperature equal to or close to the forging temperature of the workpiece. All cooling times and heating methods for the reduction A (75) described hereinabove and in other embodiments of the present disclosure are applicable to steps (79) and (80) and to all the following optional steps to allow The inner region of the workpiece will cool and heat the region of the external surface of the workpiece.

The workpiece is then forged by press (81) on the C-axis to a second height of blocking reduction spacer that is greater than the spacer height of the considerable reduction. The first and second lock reductions are applied to return the work piece, substantially, the shape prior to the forging of the work piece. While the deformation speed of the second blocking reduction may be sufficient to heating, in an adiabatic manner, an internal region of the work piece, in a non-restrictive mode, the adiabatic heating during the second blocking reduction may not occur since the deformation in which the second blocking reduction was incurred may not be enough to heat significantly, in an adiabatic way, the work piece. Optionally, the adiabatic heated internal region of the workpiece is allowed to (82) cool to a temperature equal to or close to the setting temperature of the workpiece, while the region on the external surface of the workpiece it is heated (83) to a temperature equal to or close to the forging temperature of the workpiece.

The workpiece is then forged by press for a considerable reduction spacer height (84) in the direction of the second orthogonal axis, or axis B. Hereinafter, a forging by means of press is referred to as a spacer height of considerable reduction in axis B (84) as a reduction B. After reduction B (84), optionally, the internal region adiabatically heated of the work piece is left (85) to cool to a temperature equal to or close to the temperature of forging of the workpiece, while the region on the external surface of the workpiece is heated (86) to a temperature equal to or close to the forging temperature of the workpiece.

The workpiece is then forged by press (87) on the C-axis to a first height of blocking reduction spacer that is greater than the spacer height of the considerable reduction. While the deformation rate of the first blocking reduction may be sufficient to adiabatically heat an internal region of the work piece, in a non-restrictive mode, the adiabatic heating during the first blocking reduction may not occur. that the deformation in which the first blocking reduction is incurred may not be sufficient to heat, significantly adiabatically, the work piece. Optionally, the adiabatic heated internal region of the work piece is allowed to cool to a temperature equal to or close to the workpiece forging temperature, while the region on the external surface of the workpiece it is heated (89) to a temperature equal to or close to the forging temperature of the workpiece.

The workpiece is then forged by press (90) on the A axis to a second height of blocking reduction spacer which is greater than the spacer height of the considerable reduction. The first and second lock reductions are applied to return the work piece, substantially, the shape prior to the forging of the work piece. While the deformation rate of the second blocking reduction may be sufficient to adiabatically heat an internal region of the work piece, in a non-restrictive mode, the adiabatic heating during the second blocking reduction may not occur. that the deformation in which the second blocking reduction was incurred may not be sufficient to heat the workpiece significantly adiabatically. Optionally, the adiabatic heated inner region of the workpiece is allowed to cool to a temperature equal to or close to the workpiece forging temperature, while the region on the external surface of the workpiece is cooled. it is heated (92) to a temperature equal to or close to the forging temperature of the workpiece.

The workpiece is then forged by press for a considerable reduction spacer height (93) in the direction of the third orthogonal axis, or axis C. Hereinafter referred to forging by press is referred to a spacer height of considerable reduction in the C axis (93) as a reduction C. After the reduction C (93), optionally, the internal region adiabatically heated of the work piece is left (94) to cool to a temperature equal to or close to the forging temperature of the workpiece, while the region on the external surface of the workpiece is heated (95) to a temperature equal to or close to the forging temperature of the workpiece.

The workpiece is then forged by press (96) on the A axis to a first height of blocking reduction spacer that is greater than the spacer height of the considerable reduction. While the deformation rate of the first blocking reduction may be sufficient to adiabatically heat an internal region of the work piece, in a non-restrictive mode, the adiabatic heating during the first blocking reduction may not occur. that the deformation in which incurred in the first blocking reduction may not be enough to warm, significantly adiabatically, the work piece. Optionally, the adiabatic heated inner region of the work piece is allowed to cool to a temperature equal to or close to the workpiece forging temperature, while the region on the external surface of the workpiece it is heated (98) to a temperature equal to or close to the forging temperature of the workpiece.

The workpiece is then forged by press (99) on the B axis to a second height of blocking reduction spacer that is greater than the spacer height of the considerable reduction. The first and second lock reductions are applied to return the work piece, substantially, the shape prior to the forging of the work piece. While the deformation rate of the second blocking reduction may be sufficient to adiabatically warm an internal region of the work piece, in a non-restrictive mode, the adiabatic heating during the second blocking reduction may not occur. that the deformation in which the second blocking reduction was incurred may not be sufficient to warm significantly, in an adiabatic way, the work piece. Optionally, the adiabatic-heated internal region of the workpiece is allowed to (100) cool to a temperature equal to or close to the setting temperature of the workpiece, while the region on the external surface of the workpiece it is heated (101) to a temperature equal to or close to the forging temperature of the workpiece.

With reference to Figure 5, in non-exhaustive modalities, one or more of the stages of forging by press (75), (78), (81), (84), (87), (90), (93), (96) and (99) are repeated (102) until a total deformation of at least 1.0 is reached in the titanium alloy workpiece. In another non-exhaustive mode, one or more of the stages of forging by press (75), (78), (81), (84), (87), (90), (93), (96) and (99) are repeated (102) until a total strain in a range of at least 1.0 to less than 3.5 is reached in the titanium alloy workpiece. It will be recognized that after achieving the desired deformation of at least 1.0 or alternatively the desired deformation in a range of at least 1.0 to less than 3.5 in any of the stages of forging by press (75), (78 ), (81), (84), (87), (90), (93), (96) and (99), the equilibrium stages (ie, allow the internal region of the workpiece to cool (76), (79), (82), (85), (88), (91), (94), (97) or (100) and heat the external surface of the workpiece (77), (80), (83), (86), (89), (92), (95), (98) or (101)) are not necessary and the work piece can be cooled to room temperature. In a non-restrictive embodiment, the cooling comprises liquid inactivation, such as, for example, inactivation with water. In another non-exhaustive embodiment, the cooling comprises cooling with a cooling speed of cooling by air or more quickly.

The process described above includes a repeated sequence of press forging at a considerable reduction spacer height followed by press forging to a first and second lock reduction spacer heights. A forging sequence representing a total MAF cycle as described in the non-exhaustive modality described above can be represented as A-B-C-B-C-A-C-A-B, where the reductions (impacts) that are in bold and underlined are forged by press at a height of reduction spacer considerable and reductions that are not bold or underlined are first or second block reductions. It will be understood that all press-forging reductions, including press forgings at considerable reduction spacer heights and first and second block reductions, of the MAF processes according to the present disclosure are carried out with a high deformation velocity which is sufficient to adiabatically heat the internal region of the workpiece, for example, and not restrictively, a strain rate in the range of 0.2 s1 to 0.8 s1, or in the range of 0.2 s_1 to 0.4 s1. It will also be understood that adiabatic heating may not occur, substantially, during the first and second block reductions due to the lower degree of deformation in these reductions, compared to the considerable reductions. It will also be understood that, as optional steps, the forging by intermediate successive press reduces the adiabatic heating of the internal region of the workpiece, which is allowed to cool to a temperature equal to or close to the workpiece forging temperature. , and the outer surface of the workpiece is heated to a temperature equal to or close to the setting temperature of the workpiece by the thermal management system described herein. It is believed that these optional steps may be more beneficial when the method is used to process larger work pieces. It is further understood that the embodiment of the forging sequence ABCBCACAB described herein may be repeated in whole or in part until a total deformation of at least 1.0 or in the range of at least 1.0 to less is achieved. 3.5 in the work piece.

The protrusion in the workpiece is the result of a combination of a die cutout of the surface and the presence of warmer material near the center of the workpiece. As the protrusion increases, the centers of each face are subjected to gradually triaxial loads that initiate cracking. In the sequence A-B-C-B-C-A-C-A-B, the use of intermediate blocking reductions at each forging by press with respect to a considerable reduction spacer height reduces the tendency of cracking in the workpiece. In a non-restrictive mode, when the workpiece is in the form of a cube, the first height of blocking reduction spacer for a first blocking reduction may be at a Spacer height which is 40% -60% greater than the height of spacer of considerable reduction. In a non-restrictive embodiment, when the workpiece is in the form of a cube, the second height of blocking reduction spacer for the second blocking reduction may be a spacer height that is 15% -30% greater than the height of spacer of considerable reduction. In another non-limiting embodiment, the first spacer height of the blocking reduction can be substantially equivalent to the second spacer height of the blocking reduction.

In non-exhaustive modalities of multi-axis forging of high-speed deformation managed thermally, according to the present description, then after a total deformation of at least 1.0 or in the range of at least 1.0 to less than 3.5, the workpiece comprises a particle size of alpha grain of 4 mm or less, which is considered an ultra fine grain size (UFG). In a non-exhaustive embodiment, according to the present description, applying a total deformation of at least 1.0 or in the range of at least 1.0 to less than 3.5, produces equiaxed grains.

In a non-exhaustive embodiment of a process according to the present description comprising a multi-axis forging and the use of the optional thermal management system, the interface of the workpiece die press is lubricated with lubricants known per se. the expert in the art, such as, but not limited to, graphite, glasses and / or other known solid lubricants.

In certain non-exhaustive embodiments of the methods according to the present disclosure, the workpiece comprises a titanium alloy selected from alpha + beta titanium alloys and metastable beta titanium alloys. In another non-exhaustive embodiment, the workpiece comprises an alpha + beta titanium alloy. In yet another non-exhaustive embodiment, the workpiece comprises a metastable beta titanium alloy. In a non-exhaustive embodiment, a titanium alloy processed by the method according to the present disclosure comprises precipitation and alpha phase growth kinetics which are slower than those of the Ti-6-4 alloy (UNS R56400) and can be made reference to said kinetics in the present as "slower alpha kinetics". In a non-exhaustive modality, the slowest alpha kinetics are achieved when the diffusivity of the alloy species with slower diffusion in the titanium alloy is slower than the diffusivity of aluminum in the Ti-6-4 alloy at the beta transus temperature (Tb). For example, the Ti-6-2-4-2 alloy exhibits alpha kinetics slower than the Ti-6-4 alloy as a result of the presence of additional grain attachment elements., such as silicon, in the Ti-6-2-4-2 alloy. Also, the Ti-6-2-4-6 alloy has alpha kinetics slower than the Ti-6-4 alloy as a result of the presence of additions of alloy beta stabilizers, such as a higher molybdenum content than the alloy T-6-4. The result of the slower alpha kinetics in these alloys is that the annealing of the alloys Ti-6-2-4-6 and Ti-6-2-4-2 before the MAF of high speed of deformation produces a size of relatively stable and fine alpha ribbon and a beta phase structure compared to the Ti-6-4 alloy and certain other titanium alloys that exhibit faster alpha phase growth and precipitation kinetics than the Ti-6-2-4 alloys -6 and Ti-6-2-4-2. The phrase "slower alpha kinetics" was discussed in more detail above in the present description. Examples of titanium alloys that can be processed by methods of methods according to the present disclosure include, in a non-limiting manner. exhaustive, the alloy Ti-6-2-4-2, the alloy Ti-6-2-4-6, the alloy ATI 425 ° (alloy Ti-4AI-2.5V), the alloy Ti-6-6-2 and the Ti-6AI-7Nb alloy.

In a non-exhaustive embodiment of the method according to the present disclosure, beta annealing comprises: heating the workpiece to a beta annealing temperature; maintaining the workpiece at the annealing temperature beta for a sufficient annealing time to form a 100% beta-phase microstructure of titanium; and cooling the workpiece directly to a temperature equal to or close to the forging temperature of the workpiece. In certain non-exhaustive modalities, the annealing temperature beta is in a temperature range that includes the beta transus temperature of the titanium alloy up to 300 ° F (111 ° C) above the beta transus temperature of the titanium alloy. Non-exhaustive modalities include a beta annealing time of 5 minutes to 24 hours. A person skilled in the art, after reading the present description, will understand that other beta annealing temperatures and beta annealing times are within the scope of the embodiments of the present disclosure and that, for example, relatively larger work pieces may need relatively high beta-annealing temperatures and / or longer annealing times to form a 100% beta-phase titanium microstructure.

In certain non-restrictive embodiments in which the workpiece is maintained at the annealing temperature beta to form a 100% beta-phase microstructure of titanium, the workpiece can also be deformed in plastic form at a plastic deformation temperature in the beta phase field of the titanium alloy before cooling the workpiece to a temperature equal to or close to the setting temperature of the workpiece or at room temperature. The plastic deformation of the workpiece may comprise at least one of extrusion, forging by reinforcement and of multiple axes of high deformation speed that forge the workpiece. In a non-restrictive embodiment, the plastic deformation in the beta-phase region comprises a forging by underlining of the workpiece to a bending deformation beta in the range of 0.1 to 0.5. In certain non-exhaustive modes, the temperature of the plastic deformation is in a temperature range that includes the beta temperature transus of the titanium alloy up to 300 ° F (111 ° C) on the transus beta temperature of the titanium alloy.

Figure 6 is a graph of the time-temperature thermomechanical process for a non-restrictive method of plastic deformation of the workpiece on the transus ion temperature and direct cooling to the workpiece's forging temperature. In Figure 6, a non-exhaustive method 200 comprises heating 202 a workpiece comprising a titanium alloy having precipitation and alpha growth kinetics that are slower than those of the Ti-6-4 alloy, for example, a an annealing temperature of beta 204 over the beta transus 206 temperature of the titanium alloy and maintaining or "soaking" the workpiece at the annealing temperature beta 204 to form a beta-phase titanium microstructure in the workpiece. In a non-exhaustive mode according to the present description, after soaking 208, the work piece can be deformed, in a plastic form, 210. In a non-exhaustive mode, the plastic deformation 210 comprises forging by reinforcement. In a non-restrictive embodiment, the plastic deformation 210 comprises forging by undercuts at a rectilinear tension of 0.3. In a modality not exhaustively, the plastic deformation 210 comprises thermally managed deformation high speed multi-axis forging (not shown in Figure 6) at a beta annealing temperature.

Even with reference to Figure 6, after the plastic deformation 210 in the field of the beta phase, in a non-restrictive mode the workpiece is cooled 212 to a forging temperature of the workpiece 214 in the phase field alpha + beta of the titanium alloy. In a non-exhaustive mode, cooling 212 comprises cooling by air or cooling at a speed faster than that achieved through air cooling. In another non-exhaustive embodiment, cooling comprises liquid inactivation, such as, but not limited to, inactivation with water. After cooling 212, the workpiece is subjected to multi-axis forging of high deformation speed 214 according to certain non-exhaustive embodiments of the present description. In the non-exhaustive mode of Figure 6, the work piece is forged by impact or press 12 times, that is, the three orthogonal axes of the work piece are forged by non-sequential press a total of 4 times each . In other words, with reference to Figures 2 and 6, the cycle including steps (a) - (optional b), (c) - (optional d) and (e) - (optional f) is carried out 4 times. In the non-exhaustive mode of Figure 6, after a multi-axis forging sequence involving 12 impacts, the total deformation may be equal to, for example, at least 1.0 or may be in the range of at least 1 , 0 to less than 3.5. After multi-axis forging 214, the workpiece is cooled 216 at room temperature. In a non-exhaustive mode, the cooling 216 comprises cooling by air or cooling at a higher speed than that obtained through air cooling, but other forms of cooling, such as, but not limited to, fluid or liquid inactivation. they are within the scope of the modalities described herein.

One non-limiting aspect of the present disclosure includes a multi-axis forging of high-speed deformation at two temperatures in the alpha + beta phase field. Figure 7 is a graph of a thermomechanical temperature-time process for a non-exhaustive method according to the present disclosure which comprises subjecting the titanium alloy workpiece to multi-axis forging. first temperature of titanium piece forging; optionally using a non-exhaustive mode of a thermal management feature described hereinabove; cooling to a second workpiece forging temperature in the alpha + beta phase; subjecting the titanium alloy workpiece to the second forging temperature of the workpiece to multi-axis forging; and optionally using a non-exhaustive mode of the thermal management feature described herein.

In Figure 7, a non-exhaustive method 230 according to the present disclosure comprises heating the workpiece to an annealing temperature of beta 234 over the transus 236 temperature of the alloy and holding or soaking 238 the workpiece to the Beta annealing temperature 234 to form a beta phase microstructure in the titanium alloy workpiece. After soaking 238, the work piece can be deformed in a plastic form 240. In a non-exhaustive mode, the plastic deformation 240 comprises forging by reinforcement. In another non-exhaustive embodiment, the plastic deformation 240 comprises forging by undercuts at a deformation of 0.3. In still In another non-exhaustive embodiment, the plastic deformation 240 of the workpiece comprises a high-speed multi-axis forging (not shown in Figure 7) at a beta annealing temperature.

Even with reference to Figure 7, after the plastic deformation 240 in the field of the beta phase, the workpiece is cooled 242 at a first setting temperature of the workpiece 244 in the alpha + beta phase field of the titanium alloy. In non-restrictive modalities, the cooling 242 comprises one of air cooling and liquid inactivation. After cooling 242, the workpiece is subjected to multi-axis forging of high deformation speed 246 at the first setting temperature of the workpiece and a thermal management system is optionally employed in accordance with the non-working modes. taxatives described in this. In the non-restrictive embodiment of Figure 7, the work piece is forged by press or impact at the first workpiece forging temperature 12 times with 90 ° of rotation between each impact, ie, the three orthogonal axes of the work piece is subjected to forging by press 4 times each. In other words, with Referring to Figure 2, the cycle including steps (a) - (optional b), (c) - (optional d) and (e) - (optional f) is carried out 4 times. In the non-restrictive embodiment of Figure 7, after subjecting the workpiece to the forging of high deformation high-speed multiple axes 246 at the first forging temperature of the workpiece, 248 is cooled to a second forging temperature. of the work piece 250 in the field of the alpha + beta phase. After cooling 248, the work piece is subjected to multi-axis forging of high deformation speed 250 at the second forging temperature of the workpiece and a thermal management system is optionally employed in accordance with the non-exhaustive modes described herein. In the non-exhaustive mode of Figure 7, the work piece is subjected to forging by press or impact at a second workpiece forging temperature a total of 12 times. It is recognized that the amount of impacts applied to the titanium alloy workpiece at the first and second setting temperatures of the workpiece may vary depending on the desired rectilinear deformation and the desired final grain size, and the amount of appropriate impacts can be determined without undue experimentation considering the present description. After multi-axis forging 250 at the second forging temperature of the workpiece, the workpiece is cooled 252 to room temperature. In non-restrictive modes, cooling 252 comprises one of cooling by air and inactivation by liquid up to room temperature.

In a non-restrictive mode, the first setting temperature of the workpiece is in a first range of workpiece forging temperature of more than 100 ° F (55.6 ° C) below the beta transus temperature of the titanium alloy up to 500 ° F (277.8 ° C) below the beta transus temperature of the titanium alloy, that is, the first forging temperature of the workpiece Ti is in the range of Tp - 100 ° F > Tc > Tp 500 ° F. In a non-exhaustive mode, the second setting temperature of the workpiece is a second range of workpiece forging temperature of more than 200 ° F (277.8 ° C) below the beta transus temperature of the workpiece. the titanium alloy up to 700 ° F (388.9 ° C) below the beta transus temperature, that is, the second forging temperature of the workpiece T2 is in the range of Tp 200 ° F > T2 Tb - 700 ° F. In a non-exhaustive embodiment, the titanium alloy workpiece comprises the alloy Ti-6-2-4-2; 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).

Figure 8 is a graph of the thermomechanical temperature-time process of a non-exhaustive method according to the present description for plastic deformation of a workpiece comprising a titanium alloy on the temperature of beta transus and cooling the workpiece up to a forging temperature of the workpiece, while simultaneously using a high-speed, multi-axis forging deformation with thermally administered workpiece in accordance with non-exhaustive modalities of the present. In Figure 8, a non-exhaustive method 260 for using a high-speed multi-axis forging to refine grains of a titanium alloy comprises heating the workpiece to an annealing temperature of beta 264 over the beta transus 266 temperature of the titanium alloy and holding or soaking 268 the work piece at the annealing temperature beta 264 to form a total beta phase microstructure in the work piece. After soaking 268 the work piece at the annealing temperature beta, the work piece is deformed in a plastic form 270. In a non-exhaustive mode, the plastic deformation 270 may comprise a multi-axis forging of high speed deformation managed thermally. In a non-restrictive embodiment, the workpiece is repeatedly subjected to multi-axis high-speed forging 272 by the optional thermal management system as described herein as the workpiece is cooled through the beta temperature transus Figure 8 shows three stages of intermediate high-speed deformation 272 multi-axis forging, but it will be understood that there may be more or less intermediate multi-axis forging stages 272 of intermediate deformation, as desired. The intermediate deformation high speed multi-axis forging stages 272 mediate the initial deformation high-speed multi-axis forging step 270 at the soaking temperature and the high-speed multi-axis forging step of final deformation in the Phase field alpha + beta 274 of the titanium alloy. Although Figure 8 shows a stage of high-speed multiple-axis forging of final deformation where the temperature of the workpiece continues completely in an alpha + beta phase field, it will be understood after reading the present description that more than one multi-axis forging stage in the alpha + beta phase field can be carried out for refinement of the additional grain. According to non-exhaustive embodiments of the present description, at least one step of multi-axis forging of high-speed final deformation is carried out, in its entirety, at temperatures in the field of the alpha + beta phase of the workpiece. titanium alloy work.

Since the multi-axis forging stages 270, 272, 274 are carried out while the workpiece is cooled through the beta transus temperature of the titanium alloy, a method embodiment such as that shown in FIG. Figure 8 is referred to herein as "multi-axis forging of high velocity deformation through beta transus". In a non-exhaustive embodiment, the thermal management system 33 of Figure (33 of Figure 3) is used in a multi-axis forging via beta transus to maintain the temperature of the workpiece at a uniform or substantially uniform temperature. uniform before each impact at each temperature of multiple forging axes through beta transus and, optionally, to slow down the cooling rate. After the final multi-axis forging 274, the workpiece temperature in the alpha + beta phase field, the workpiece is cooled 276 to room temperature. In a non-exhaustive mode, cooling 276 comprises air cooling.

Non-exhaustive embodiments of multi-axis forging using the thermal management system, as described hereinabove, can be used to process titanium alloy workpieces having cross-sections greater than 4 square inches using equipment Forging by conventional press and the size of the cubic workpieces can be graduated to suit the capabilities of an individual press. It was determined that the alp lamellae or strips of the annealed structure b are easily broken into uniform fine alpha grains at workpiece forging temperatures described in non-limiting embodiments herein. It was also determined that decreasing the temperature of the forging of the workpiece decreases the alpha particle size (grain size).

Without wishing to adhere to any particular theory, it is believed that the refinement of the grain that occurs in non-exhaustive modalities of multi-axis forging of high-speed deformation thermally managed in accordance with the present disclosure occurs by meta-dynamical recrystallization. In the prior art of the multi-axis slow-speed forging process, dynamic recrystallization occurs instantaneously during the application of the deformation to the material. It is believed that in multi-axis forging high-speed deformation according to the present disclosure, meta-dynamical recrystallization occurs at the end of each impact of deformation or forging, while at least the internal region of the workpiece is hot by adiabatic heating. The residual adiabatic heating, the cooling times of the internal region and the heating of the surface region influence the degree of refinement of the grain in non-exhaustive methods of multi-axis forging of high deformation thermally managed according to the present description.

The inventors of the present invention further developed alternative methods according to the present disclosure which provide certain advantages in relation to a process as described above including multi-axis forging and using a thermal management system and a cubic workpiece comprising an alloy of titanium. It is believed that one or more of (1) the cube workpiece geometry used in certain thermally managed multi-axis forging modes described herein, (2) die cooling (ie, letting the temperature of the dies fall significantly below the workpiece forging temperature), and (3) the use of high deformation speeds can concentrate, Disadvantageously, the deformation within a central region of the work piece.

Alternative methods according to the present disclosure can generally obtain fine grain sizes, very fine grains or uniform ultra fine grains through a titanium alloy workpiece the size of a bar. In other words, a piece of work processed by such alternative methods may include the desired grain size, such that an ultrafine grain microstructure, through the workpiece, and not only in a central region of the workpiece. The non-exhaustive modalities of said alternative methods comprise the "multiple extrusion and extrusion" steps carried out on bars having cross-sections greater than 4 square inches. It is intended that the multiple extrusion and extrusion stages confer uniform microstructures of fine grains, very fine grains or ultra-fine grains through the workpiece, substantially preserving the original dimensions of the workpiece. Since the present alternative methods include multiple extrusion and recessing steps, these are referred to herein as the modalities of the "MUD" method. The MUD method includes intense plastic deformation and can produce uniform ultrafine grains in titanium alloy workpieces the size of a bar (eg, 30 inches (76.2 cm) in length). In non-restrictive modes of the MUD method according to the present disclosure, the deformation rates used for the step-up forging and the extrusion forging are in the range of 0.001 s 1 to 0.02 s1. In In contrast, the deformation rates typically used for conventional open die extrusion and upsetting forgings are in the range of 0.03 s1 to 0.1 s1. The deformation speed for MUD is sufficiently slow to avoid adiabatic heating in the workpiece in order to keep the temperature of the forging controlled, however the deformation speed is acceptable for commercial practices.

A schematic representation of the non-restrictive modalities of the MUD method is provided in Figure 9, and a flow diagram of certain modalities of the MUD method is provided in Figure 10. With reference to Figures 9 and 10, a non-exhaustive method 300 for refining grains in a workpiece comprising a titanium alloy using multi-upset and multi-extrusion forging steps comprising heating an elongated titanium alloy workpiece 302 to a workpiece forging temperature in the field of the alpha + beta phase of the titanium alloy. In a non-restrictive embodiment, the shape of the elongate workpiece is cylinder-shaped or similar to a cylinder. In another modality not restrictive, the shape of the workpiece is an octagonal cylinder or a straight octagon.

The elongate workpiece has an initial cross-sectional dimension. For example, in a non-exhaustive mode of the MUD method according to the present disclosure in which the initial workpiece is a cylinder, the initial cross-sectional dimension is the diameter of the cylinder. In a non-exhaustive mode of the MUD method according to the present description in which the initial workpiece is an octagonal cylinder, the initial cross-sectional dimension is the diameter of the circumscribed circle of the octagonal cross-section, ie the diameter of the circle that passes through all vertices of the octagonal cross section.

When the elongate workpiece is at the forging temperature of the workpiece, the workpiece is forged by upsetting 304. After the forging by upsetting 304, in a non-restrictive mode, the workpiece is rotated 90 degrees to orientation 306 and then subjected to multi-pass extrusion forging 312. Actual rotation of the workpiece is optional, and the The objective of the step is to arrange the workpiece in the correct orientation (refer to Figure 9) related to a forging device for the multiple pass extrusion stages 312 following.

Multi-pass extrusion forging involves gradually rotating (represented by arrow 310) the workpiece in a rotational direction (indicated by the direction of arrow 310), followed by extrusion forging 312 of the workpiece after increase in turnover In non-restrictive embodiments, the forgings that rotate gradually 310, and by extrusion 312 are repeated until the work piece comprises the initial transverse dimension. In a non-restrictive embodiment, the stages of forging by reinforcement and the forging by extrusion of multiple passes are repeated until a total deformation of 1.0 is achieved in the work piece. Another non-exhaustive method comprises repeating the heating, forging by reinforcement and forging by extrusion of multiple passes until achieving a total deformation in the range of at least 1.0 to less than 3.5 in the workpiece. In yet another non-exhaustive modality, the stages of heating, of forging by reinforcement and the forging by extrusion of multiple passes are repeated until a total deformation of 10 is achieved in the work piece. It is anticipated that when a total deformation of 10 is conferred to the MUD forging, an ultrafine alpha grain microstructure is produced and that increasing the total deformation conferred to the work piece results in smaller average grain sizes.

One aspect of the present disclosure is to employ a deformation rate during the multi-pass extrusion and reinforcement steps that is sufficient to result in intense plastic deformation of the titanium alloy workpiece which, in non-exhaustive embodiments, additionally result in ultra-fine grain sizes. In a non-restrictive embodiment, a deformation rate used in the upsetting forging is in the range of 0.001 s1 to 0.003 s1. In another non-exhaustive embodiment, a deformation rate used in the multi-pass extrusion forging stages is in the range of 0.01 s1 to 0.02 s1. It was described in Application 538 that the rates of deformation in these ranges do not result in adiabatic heating of the workpiece, which It allows the control of the temperature of the work piece and was considered sufficient for an economically acceptable commercial practice.

In a non-exhaustive mode, after completing the MUD method, the work piece substantially has the original dimensions of the initial elongated article, such as, for example, the cylinder 314 or the octagonal cylinder 316. In another non-exhaustive mode, After completing the MUD method, the work piece has substantially the same cross section as the initial work piece. In a non-restrictive embodiment, a single upset requires several extrusion impacts and intermediate rotations to return to the workpiece a shape that includes the initial cross-section of the workpiece.

In a non-exhaustive modality of the MUD method where the workpiece is in the form of a cylinder, for example, the extrusion forging and gradually rotating additionally comprising multiple stages of rotation of the cylindrical workpiece increments of 15 ° and subsequently forging by extrusion, until the cylindrical workpiece is rotated through 360 ° C and forged by extrusion at each increment. In a non-exhaustive mode of the MUD method where the workpiece has a cylinder shape, after each reinforcement forging, twenty-four stages of extrusion forging are employed with intermediate gradual rotation between extrusion forging stages to substantially return the workpiece. work its initial cross-sectional dimension. In another non-exhaustive mode where the workpiece is in the form of an octagonal cylinder, for example, the extrusion and additionally rotationally forging that comprises multiple stages of rotation of the cylindrical workpiece increases of 45 ° and subsequently the extrusion forging, until the cylindrical workpiece is rotated through 360 ° C and is forged by extrusion at each increment. In a non-restrictive mode of the MUD method where the workpiece has the shape of an octagonal cylinder, after each reinforcement forging, eight stages of forging are used separated by intermediate gradual rotation to substantially return to the workpiece its cross-sectional dimension initial. It was observed in non-exhaustive modalities of the MUD method that the manipulation of an octagonal cylinder by handling the equipment was more accurate than the handling of a cylinder. by managing the equipment. It was also observed that the manipulation of an octagonal cylinder by handling the equipment in a non-exhaustive modality of a MUD method was more accurate than handling a cubic work piece using hand grippers in non-exhaustive modalities of the high-speed MAF process of deformation managed thermally described herein. It will be recognized upon consideration of the present disclosure that other extrusion forging sequences may be used, each including a number of stages of extrusion forging and intermediate gradual rotations of a particular amount of degrees, for other forms of cross-section bars for the purpose that the final shape of the workpiece after the extrusion forging is substantially the same as the initial shape of the workpiece before the reinforcement forging. Said other possible sequences may be determined by a person skilled in the art without undue experimentation and are included within the scope of the present disclosure.

In a non-exhaustive mode of the MUD method according to the present disclosure, a setting temperature of the workpiece comprises a temperature within a Forging temperature range of the workpiece. In a non-restrictive mode, the workpiece forging temperature is in a working temperature forging temperature range of 100 ° F (55.6 ° C) below the beta transus temperature (Tp) of titanium alloy up to 700 ° F (388.9 ° C) below the beta transus temperature of the titanium alloy. In yet another non-exhaustive mode, the workpiece forging temperature is in a range of 300 ° F (166.7 ° C) below the beta transus temperature of the titanium alloy to 625 ° F (347 ° C). C) below the beta transus temperature of the titanium alloy. In a non-restrictive embodiment, the lower end of a workpiece forging temperature range is a temperature in the alpha + beta phase field at which no substantial damage occurs on the surface of the workpiece during impact of forging, as can be determined without undue experimentation by an expert in the art.

In a non-exhaustive mode of the MUD method according to the present disclosure, the temperature range of forging of the workpiece for a Ti-6-2-4-2 alloy, having a transus (Tp) temperature of about of 1820 ° F (993.3 ° C), can be, for example, 1120 ° F (604.4 ° C) to 1720 ° F (937.8 ° C) or in another mode it can be 1195 ° F (646.1 ° C) at 1520 ° F (826.7 ° C).

Non-exhaustive modalities of the MUD method include multiple reheating stages. In a non-exhaustive embodiment, the titanium part of the titanium alloy is heated to the setting temperature of the workpiece after subjecting the titanium alloy workpiece to undercuts. In another non-exhaustive embodiment, the titanium alloy workpiece is heated to the forging temperature of the workpiece before a step of extrusion forging by multiple-pass extrusion. In another non-exhaustive mode, the workpiece is heated as much as is needed to return the actual temperature of the workpiece to or near the setting temperature of the workpiece after a step of forging by undercuts or extrusion.

It was determined that the modalities of the MUD method confer redundant work or extreme deformation, which is also referred to as intense plastic deformation, which aims to create ultra-fine grains in a workpiece comprising a titanium alloy. Without wishing to cling to any particular theory of operation, it is believed that the round or octagonal cross-sectional shape of the cylindrical or octagonal workpieces, respectively, distributes the deformation more evenly than the workpieces of square or rectangular cross sections. Rectangular along the cross-sectional area of the workpiece during a MUD method. The damaging effect of friction between the workpiece and the forging die is also reduced by reducing the area of the workpiece in contact with the die.

In addition, it was also determined that decreasing the temperature during the MUD method reduces the final grain size to a size that is characteristic of the specific temperature that is being used. With reference to Figure 10, in a non-exhaustive modality of a method 400 for refining the grain size of a workpiece, after processing the work piece by the MUD method at the workpiece wrought temperature, The temperature of the workpiece can be cooled 416 to a second forging temperature of the workpiece. In a non-exhaustive modality, after cooling the workpiece to the second setting temperature of the workpiece, the workpiece is forged by upsetting at the second setting temperature of the workpiece 418. The workpiece is rotated 420 or another mode is oriented relative to the forging press for the subsequent stages of extrusion forging. The workpiece is forged by extrusion in multiple stages at the second forging temperature of the workpiece 422. The multi-stage extrusion forging at the second forging temperature of the workpiece 422 comprises increasing rotation of the workpiece 424. of working in a rotary direction (refer to Figure 9) and performing rewinding at the second setting temperature of the workpiece of the workpiece 426 after each increment of rotation. In a non-restrictive embodiment, the steps of upset forging, which rotate in increment 424, and extrusion forging are repeated 426 until the workpiece comprises the transverse start dimension. In another non-exhaustive embodiment, the steps of forging by reinforcement in the second temperature of the workpiece 418, rotation 420, and extrusion forging in multiple stages are repeated until a total deformation of at least 1.0 is achieved, or in the interval 1.0 to less than 3.5, or up to 10 or greater in the workpiece. It is recognized that the MUD method can be continued until any total deformation is imparted to the titanium alloy workpiece.

In a non-exhaustive embodiment comprising a multi-temperature MUD method mode, the setting temperature of the workpiece, or a first setting temperature of the workpiece, is about 1600 ° F (871.1 ° C). ), and the second forging temperature of the workpiece is around 1500 ° F (815.6 ° C). The subsequent workpiece forging temperatures which are lower than the first and second forging temperature of the workpiece, such as a third workpiece forging temperature, a fourth forging temperature of the workpiece of work, etc., are within the scope of non-exhaustive modalities of the present description.

As the forging proceeds, the refinement of the grain results in the reduction of the flow stress at a fixed temperature. It was determined that to decrease the temperature of forging for the stages of reinforcement and extrusion maintains the constant flow stress and increases the speed of microstructural refinement. It is anticipated that in non-exhaustive modes of MUD according to the present disclosure, a total deformation of at least 1.0, in a range of at least 1.0 to less than 3.5, or up to 10 results in a microstructure Ultra-fine alpha equiaxed grain in titanium alloy workpieces, and that the lower temperature of a MUD method of two temperatures (or multiple temperatures) can determine the final grain size after a total deformation of up to 10 is imparted in the MUD forging.

One aspect of the present disclosure includes the possibility that after processing a work piece by the MUD method, the subsequent deformation steps are performed without swelling the size of the refined grain, as long as the temperature of the workpiece is not heated subsequently on the beta transus temperature of the titanium alloy. For example, in a non-exhaustive mode, a subsequent deformation practice following the MUD method may include extrusion forging, multiple extrusion forging, undercurrent forging or any combination of two or more of these forging techniques to temperatures in the alpha + beta phase field of the titanium alloy. In a non-restrictive embodiment, the post-deformation or the forging stages include a combination of multi-pass extrusion forging, underwire forging and extrusion forging to reduce the transverse dimension of the start of the cylinder-like workpiece or other workpiece. work elongated to a fraction of the transverse dimension, such as, for example, non-exhaustively, one half of the transverse dimension, one quarter of the transverse dimension, etc., while maintaining a uniform structure of fine grain, one grain Very fine or ultra-fine grain in the titanium alloy workpiece.

In a non-exhaustive mode of a MUD method, the workpiece comprises a titanium alloy selected from the group consisting of an alpha + beta titanium alloy and a metastable beta titanium alloy. In another non-exhaustive embodiment of a MUD method, the workpiece comprises an alpha + beta titanium alloy. In yet another non-exhaustive embodiment of the multiple recessing and extrusion process described herein, the workpiece comprises a metastable beta titanium alloy. In a modality not For a MUD method, the workpiece is a titanium alloy selected from an alloy Ti-6-2-4-2, an alloy Ti-6-2-4-6, an alloy of titanium ATI 425 ° (TÍ-4AI-2.5V), and an alloy Ti-6-6-2.

Before heating the workpiece to the forging temperature of the workpiece in the alpha-beta phase field according to the MUD modalities of the present description, in a non-exhaustive mode the workpiece can be heated to a beta annealing temperature, maintained at the temperature of the beta anneal during a sufficient annealing time to form a titanium microstructure of 100% beta phase in the workpiece, and cooled to room temperature. In a non-restrictive embodiment, the annealing temperature beta is in a beta annealing temperature range that includes the transus beta temperature of the titanium alloy up to 300 ° F (111 ° C) above the transus ion temperature of the titanium alloy . In a non-restrictive mode, the annealing time is from 5 minutes to 24 hours.

In a non-exhaustive mode, the work piece is a bar that is covered in certain surfaces or in all with a lubricating coating that reduces friction between the work piece and the forging dies. In a non-restrictive embodiment, the lubricant coating is a solid lubricant such as, but not limited to, one of graphite and a glass lubricant. Other lubricant coatings known today or in the future by a person skilled in the art are within the scope of the present disclosure. Furthermore, in a non-exhaustive mode of the MUD method that uses cylinder-type work pieces or other elongated shapes, the contact area between the work piece and the forging dies is small compared to the contact area in multiple forgings. Shafts of a cube-shaped work piece. For example, with a 4-inch cube, two of the 4-inch by 4-inch whole faces of the cube are in contact with the die. With a 5-foot long bar, the length of the bar is larger than a typical 14-inch-long die, and the reduced contact area results in reduced die friction and a microstructure and macrostructure of the workpiece more uniform titanium alloy.

Before heating the work piece comprising a titanium alloy at the forging temperature of the workpiece in the field of the alpha + beta phase according to the MUD modalities of the present description, in a non-exhaustive mode, the work piece is deformed in a plastic way to a plastic deformation temperature in the beta phase change of the titanium alloy after being maintained at a sufficient annealing time to form the 100% beta phase in the titanium alloy and before cooling the alloy at room temperature. In a non-restrictive modality, the plastic deformation temperature is equivalent to the annealing temperature beta. In another non-exhaustive mode, the plastic deformation temperature is in a range of plastic deformation temperature that includes the transus ion temperature of the titanium alloy up to 300 ° F (111 ° C) over the beta transus temperature of the alloy of titanium.

In a non-restrictive mode of the MUD method, plastic deformation of the workpiece in the beta-phase field of the titanium alloy comprises at least one tracing, forging by reinforcement, and high-speed multi-axis forging. deformation in the titanium alloy workpiece. In another non-exhaustive modality, plastic deformation of the work piece in the beta phase field of the titanium alloy comprises forging by underlining and extrusion according to non-exhaustive embodiments of the present description, and where the workpiece is cooled to a temperature equal to or close to the forging temperature of the workpiece. work includes cooling with air. In yet another non-exhaustive embodiment, plastic deformation of the workpiece in the field of the beta phase of the titanium alloy comprises forging the workpiece by stressing to a reduction of 30-35% in height or another dimension, such as length Another aspect of the MUD method of the present disclosure may include heating the forging dies during forging. A non-exhaustive embodiment comprises heating the dies of a forge used to forge the workpiece at temperature in a temperature range limited by the workpiece forging temperature up to 100 ° F (55.6 ° C) below the forging temperature of the work piece.

In non-exhaustive modalities of the MUD method according to the present disclosure, a method for the production of ultra-fine granulated titanium alloys includes: a titanium alloy that has a slower growth rate and kinetics than the Ti-6-4 alloy; the annealing of the alloy to provide a fine and stable alpha ribbon structure; and a high deformation speed that forges the alloy with multiple axis, according to the present description, until reaching a total deformation of at least 1.0, or in a range of at least 1.0 to less than 3.5. The titanium alloy can be chosen from alpha + beta titanium alloys and metastable beta titanium alloys that provide a fine and stable alpha ribbon structure after growth kinetics.

It is believed that certain methods described herein can also be applied to metals and metal alloys that are not titanium alloys to reduce the grain size of the workpieces of those alloys. Another aspect of this description includes non-exhaustive modalities of a method for the forging of high-speed, multi-stage deformation of metals and metal alloys. A non-exhaustive method of the method comprises heating a workpiece comprising a metal or a metal alloy at a forging temperature of the workpiece.

After heating, the workpiece is forged at the forging temperature of the workpiece at a sufficient deformation speed to adiabatically heat an internal region of the workpiece. After the forging, a waiting period is used before the next stage of forging. During the waiting period, the temperature of the internal region adiabatically heated of the metal alloy workpiece is allowed to cool to the setting temperature of the workpiece, while at least one region of a workpiece surface of work is heated to the temperature of forging the work piece. The forging stages of the workpiece and then allowing the adiabatic heated internal region of the work piece to equilibrate with the workpiece forging temperature while heating at least one surface region of the workpiece Working of alloy metal at the temperature of forging the work piece are repeated until a desired characteristic is obtained. In a non-restrictive embodiment, the forging comprises one or more for forging with press, forging by reinforcement, forging by extrusion and forging by rolling. In another non-exhaustive embodiment, the metal alloy is selected from the group consisting of titanium alloys, zirconium and zirconium alloys, aluminum alloys, ferrous alloys and superalloys. In still other non-exhaustive embodiments, the desired feature is one or more of a imparted strain, an average grain size, a shape and a mechanical property. The mechanical properties include, but are not limited to, strength, ductility, fracture resistance and hardness.

The following examples intend to continue describing certain non-exhaustive modalities, without restricting the scope of the present invention. Those skilled in the art will understand that variations of the following examples are possible within the scope of the invention, which is defined solely by the claims.

EXAMPLE 1 An Ti-6-2-4-2 alloy bar was processed according to a commercial forging process, identified in the industry by the AMS 4976 specification number, which is typically used to process the Ti-6-2- alloy. 4-2 .. Referring to the AMS 4976 specification, those skilled in the art will understand the details of the process to achieve the mechanical properties and configuration of the microstructure in the specification. After processing, the alloy was prepared metallographically and the microstructure was evaluated microscopically. As shown in the micrograph of the prepared alloy included as Figure 11 (a), the microstructure includes alpha grains (the regions with lighter colors in the image) which is in the order of 20 mm or longer.

According to a non-limiting embodiment within the present disclosure, a 4.0-inch cube-shaped workpiece of the Ti-6-2-4-2 alloy was subjected to beta annealing at 1950 ° F (1066 ° C). ) for 1 hour and then cooled with air to room temperature. After cooling, the cube-shaped work piece subjected to beta annealing was heated to a workpiece forging temperature of 1600 ° F (871.1 ° C) and forged using four high speed MAF impacts. of deformation. The impacts were to the following orthogonal axes, in the following sequence: A-B-C-A. The impacts were at a spacer height of 3.25 inches, and the head speed was 1 inch per second. There was no deformation speed control on the press, but for the 4-inch cubes, this head speed has as a result a minimum deformation rate during the pressing of 0.25 s1. The time between successive orthogonal impacts was around 15 seconds. The total deformation applied to the work piece was 1.37. The microstructure of the Ti-6-2-4-2 alloy processed in this manner is described in the micrograph of Figure 11 (b). Most of the alpha particles (areas with softer colors) are in the order of 4 mm or less, which is substantially thinner than the alpha grains produced by the above-mentioned commercial forging process and represented by the micrograph of Figure 11 (to).

EXAMPLE 2 An Ti-6-2-4-6 alloy bar was processed according to a commercial forging process, typically used for the T-6-2-4-6 alloy, that is, according to the AMS 4981 specification. Referring to the AMS 4981 specification, the technical experts will understand the details of the process to achieve the mechanical properties and configuration of the microstructure in the specification. After processing, the alloy was prepared metallographically and the microstructure was evaluated microscopically. As shown in the micrograph of the prepared alloy shown in Figure 12 (a), the microstructure exhibits alpha grains (regions with lighter colors) that is in the order of 10 mm or longer.

In a non-exhaustive embodiment in accordance with the present disclosure, a 4.0-inch cube-shaped workpiece of the Ti-6-2-4-6 alloy was subjected to beta annealing at 1870 ° F (1066 ° C) for 1 hour and then cooled with air. After cooling, the cube-shaped work piece subjected to beta annealing was heated to a workpiece forging temperature of 1500 ° F (815.6 ° C) and forged using four high speed velocity deformation MAF impacts. The impacts went to the following orthogonal axes and followed the following sequence: A-B-C-A. The impacts were at a spacer height of 3.25 inches, and the head speed was 1 inch per second. There was no deformation speed control on the press, but for the 4 inch cubes, this spindle speed results in a minimum deformation rate during pressing of 0.25 s1. The time between successive orthogonal impacts was around 15 seconds. The total deformation applied to the work piece was 1.37.

The microstructure of the alloy processed in this way is described in the micrograph of Figure 12 (b). It is noted that most of the alpha particles (areas with softer colors) are in the order of 4 mm or less, and in any case they are finer than the alpha grains produced by the above mentioned commercial forging process and represented by the micrograph of Figure 12 (a).

EXAMPLE 3 In a non-exhaustive embodiment in accordance with the present disclosure, a 4.0-inch cube-shaped workpiece of the Ti-6-2-4-6 alloy was subjected to beta annealing at 1870 ° F (1066 ° C) for 1 hour and then cooled with air. After cooling, the cube-shaped workpiece subjected to beta annealing was heated to a workpiece forging temperature of 1500 ° F (815.6 ° C) and forged using three high-speed MAF impacts. deformation, one in each axis A, B and C (that is, the impacts went to the following orthogonal axes and in the following sequence: ABC). The impacts were at a spacer height of 3.25 inches, and the head speed was 1 inch per second. There was no deformation speed control on the press, but for 4-inch cubes, this spindle speed results in a Minimum deformation rate during pressing of 0.25 s1. The time between the successive impacts was around 15 seconds. After impact cycle A-B-C, the workpiece was reheated to 1500 ° F (815.6 ° C) for 30 minutes. The cube was subjected to MAF of high speed of deformation with an impact each one on axes A, B and C, that is, the impacts went to the following orthogonal axes and in the following sequence: A-B-C. The impacts were at the same spacer height and used the same time and head speed between impacts as used in the first A-B-C sequence of impacts. After the second sequence of impacts of A-B-C, the workpiece was reheated to 1500 ° F (815.6 ° C) for 30 minutes. The cube was then subjected to high-speed deformation MAF with an impact on each of axes A, B and C, ie, a sequence A-B-C. The impacts were at the same spacer heights and used the same time and head speed between impacts as in the first sequence of impacts A-B-C. This embodiment of a multi-axis forging process of high deformation velocity imparted a deformation of 3.46. The microstructure of the alloy processed in this way is described in the micrograph of Figure 13. It is noted that most of the alpha particles (areas with lighter colors) are in the order of 4 mm or less. It is probably believed that the alpha particles comprise individual alpha grains and that each of the alpha grains has a grain size of 4 mm or less and is equiaxed in shape.

EXAMPLE 4 In a non-restrictive embodiment according to the present disclosure, a 4.0-inch cube-shaped workpiece of Ti-6-2-4-2 alloy was subjected to beta annealing at 1950 ° F (1066 ° C) for 1 hour and then cooled with air. After cooling, the cube-shaped workpiece subjected to beta annealing was heated to a workpiece forging temperature of 1700 ° F (926.7 ° C) and held for 1 hour. Two MAF cycles of high strain rate (2 sequences of three A-B-C hits, for a total of 6 hits) were employed at 1700 ° F (926.7 ° C). The time between the successive impacts was around 15 seconds. The forging sequence was: an impact A to a top of 3 inches; an impact B to a limit of 3.5 inches; and an impact C to a limit of 4.0 inches. The forging sequence provides an even deformation to all three orthogonal axes for each MAF sequence of three impacts The spindle speed was 1 inch per second. There was no deformation speed control on the press, but for the 4 inch cubes, this spindle speed results in a minimum deformation rate during pressing of 0.25 s1. The total deformation per cycle is less than forging to a reduction of 3.25 inches in each direction, as in the previous examples.

The workpiece was heated to 1650 ° F (898.9 ° C) and subjected to high strength MAF for three additional impacts (ie, an additional A-B-C cycle subjected to high velocity strain MAF). The forging sequence was: an impact A to a top of 3 inches; an impact B to a limit of 3.5 inches; and an impact C to a limit of 4.0 inches. After the forging, the total deformation transmitted to the work piece was 2.59.

The microstructure of the forged workpiece of Example 4 is described in the micrograph of Figure 14. It is noted that most of the alpha particles (regions of lighter colors) are in a network structure. It is probably believed that alpha particles comprise individual alpha grains and that each of the alpha grains has a grain size of 4 mm or less and has equiaxed shape.

EXAMPLE 5 In a non-restrictive embodiment according to the present disclosure, a 4.0-inch cube-shaped workpiece of Ti-6-2-4-2 alloy was subjected to beta annealing at 1950 ° F (1066 ° C) for 1 hour and then cooled with air. After cooling, the cube-shaped workpiece subjected to beta annealing was heated to a workpiece forging temperature of 1700 ° F (926.7 ° C) and held for 1 hour. MAF was used, in accordance with the present disclosure, to apply 6 press forgings at a considerable reduction spacer height (A, B, C, A, B, C) to the cube-shaped workpiece. In addition, between each pressing forging at a considerable reduction spacer height of 3.25 inches, the first and second blocking reductions were carried out on the shafts to "fix" the work piece. The sequence of general forging used is as follows, where the bold and underlined impacts are press forgings at the height of the considerable reduction spacer: A-B-C-B-C-A-C-A-B-A-B-C-B-C-A-C.

The forging sequence, which includes the spacer heights of the first and the second largest block (in inches) that were used are indicated in the table below. The spindle speed was 1 inch per second. There was no strain rate control on the press, but for the 4.0 inch cubes, this spindle speed results in a minimum strain rate during pressing of 0.25 s1. The time between the impacts was around 15 seconds. The total deformation after the MAF managed thermally in accordance with this non-exhaustive modality was 2.37.

The microstructure of the workpiece forged by the process described in Example 5 is described in the micrograph of Figure 15. It is noted that most of the alpha particles (regions of lighter colors) are elongated. It is probably believed that the alpha particles comprise individual alpha grains and that each of the alpha grains has a grain size of 4 mm or less and is equiaxed in shape.

EXAMPLE 6 In a non-restrictive embodiment according to the present disclosure, a 4.0-inch cube-shaped workpiece of Ti-6-2-4-2 alloy was subjected to beta annealing at 1950 ° F (1066 ° C) for 1 hour and then cooled with air. High-speed deformation MAF was performed thermally managed, according to the present description, was performed on the work piece, which includes 6 impacts (2 ABC cycles of MAF) at 1900 ° C, with 30-second retentions between each impact. The spindle speed was 1 inch per second. There was no deformation speed control on the press, but for the 4 inch cubes, this spindle speed results in a minimum deformation rate during pressing of 0.25 s1. The sequence of 6 hits with intermediate retentions was designed to heat the surface of the piece through the beta transus temperature during MAF, and therefore it can be referred to as a high speed MAF of direct transusional deformation. The results of the process to refine surface structures and minimize cracking during subsequent forging. The workpiece was then heated to 1650 ° F (898.9 ° C), that is, below the beta transus temperature for 1 hour. MAF was applied, according to the present description, to the work piece, including 6 impacts (two MAF A-B-C cycles) with about 15 seconds between impacts. The first three impacts (the impacts in the first ABC cycle of MAF) were performed with a spacer height of 3.5 inches, and the second 3 impacts (the impacts in the second ABC cycle of MAF) were made with a height of 3.25 inch spacer. The workpiece was heated to 1650 ° C and held for 30 minutes between impacts with the 3.5 inch spacer and impacts with the 3.25 inch spacer. The smallest reduction (ie, largest spacer height) used for the first 3 impacts was designed to inhibit cracking as the smaller reduction breaks the boundary structures that can lead to cracking. The workpiece was reheated to 1500 ° F (815.6 ° C) for 1 hour.

MAF was then applied, according to the present description, using 3 cycles of A-B-C (one cycle of MAF) for reductions of 3.25 inches with 15 seconds between each impact. This sequence of heavier reductions is designed to add additional work in non-delimiting structures. The head speed of all impacts described in Example 6 was 1 inch per second.

A total deformation of 3.01 was transferred to the workpiece of Example 6. A micrograph representative of the center of the thermally managed MAF workpiece of Example 6 is shown in Figure 16 (a). A representative micrograph of the surface of the thermally managed MAF workpiece of Example 6 is presented in Figure 16 (b). The microstructure of the surface (Figure 16 (b)) is substantially refined and most of the particles and / or grains have a size of about 4 mm or less, which is an ultra-fine grain microstructure. The central microstructure shown in Figure 16 (a) shows highly refined grains, and it is likely believed that the alpha particles comprise individual alpha grains and each of the alpha grains has a grain size of 4 mm or less and is equiaxed in shape.

It will be understood that the present description illustrates those aspects of the invention pertinent to a clear understanding of the invention. Certain aspects that would be evident to the experts in the field and that, therefore, would not facilitate a better understanding of the invention have not been presented to simplify the present description. Although a limited number of embodiments of the present invention are necessarily described herein, one skilled in the art, upon consideration of the foregoing description, will recognize that many modifications and variations of the invention may be employed. It is intended that all such variations and modifications of the invention be covered by the foregoing description and the following claims.

Claims

1. A method for refining the grain size of a workpiece comprising a titanium alloy, the method comprises: subjecting the work piece to beta annealing; cooling the workpiece subjected to beta annealing at a temperature below the beta transus temperature of the titanium alloy; Y Forging the workpiece with multiple axes, where the forging of multiple axes comprises forging the workpiece with a press at a forging temperature of the workpiece in a range of setting temperature of the workpiece in the direction of a first orthogonal axis of the workpiece with a deformation speed that is sufficient for heating, adiabatically, an internal region of the workpiece, press-forging the workpiece at a forging temperature of the workpiece in the forging temperature range of the workpiece in the direction of a second orthogonal axis of the workpiece with a deformation speed that is sufficient to heat, of Adiabatic form an internal region of the workpiece, press-forging the workpiece at a forging temperature of the workpiece in the forging temperature range of the workpiece in the direction of a third orthogonal axis of the workpiece. workpiece with a deformation speed that is sufficient to heat, adiabatically, an internal region of the work piece, and repeat at least one of the forging stages with press until a total deformation of at least 1.0 is achieved in the work piece.

2. The method of claim 1, wherein at least one of the stages of press forging is repeated until a total deformation in the range of at least 1.0 to less than 3.5 is achieved in the workpiece.

3. The method of claim 1, wherein a strain rate used during pressing forging is in the range of 0.2 s1 to 0.8 s1.

4. The method of claim, wherein the workpiece comprises one of an alpha + beta titanium alloy and a metastable beta titanium alloy.

5. The method of claim 1, wherein the workpiece comprises an alloy of titanium alpha-t-beta.

6. The method of claim 4 or 5, wherein the titanium alloy comprises at least one of alloy additions of grain fixation and beta stabilization content effective to decrease phase precipitation and alpha growth kinetics.

7. The method of claim 1, wherein the workpiece comprises a titanium alloy that is selected from the alloy Ti-6AI-2Sn-4Zr-6Mo (UNS R56260), the alloy Ti-6AI-2Sn-4Zr-2Mo-0.08 Yes (UNS R54620), the Ti-4AI-2.5V alloy (UNS R54250), the Ti-6AI-7Nb alloy (UNS R56700) and the Ti-6AI-6V-2Sn alloy (UNS R56620).

8. The method of claim 1, wherein cooling the workpiece subjected to beta annealing comprises cooling the workpiece to room temperature.

9. The method of claim 1, wherein cooling the workpiece subjected to beta annealing comprises cooling the piece of work at a temperature equal to or close to the temperature of forging the work piece.

10. The method of claim 1, wherein the beta reworking of the workpiece comprises heating the workpiece to a beta annealing temperature in a beta transus temperature range of the titanium alloy up to 300 ° F (111 ° C) on the beta transus temperature of the titanium alloy.

11. The method of claim 1, wherein the beta annealing of the workpiece comprises heating the workpiece to a beta annealing temperature for a time within the range of 5 minutes to 24 hours.

12. The method of claim 1, further comprising plastic deformation of the workpiece at a plastic deformation temperature in the beta phase field of the titanium alloy before cooling the workpiece subjected to beta annealing.

13. The method of claim 12, wherein plastic deformation of the workpiece at a temperature of plastic deformation in the field of the beta phase of the titanium alloy comprises at least one extrusion, forging by reinforcement, and forging multiple axis high deformation speed in the workpiece.

14. The method of claim 12, wherein the temperature of the plastic deformation is in a range of the beta transus temperature of the titanium alloy up to 300 ° F (111 ° C) above the beta transus temperature of the titanium alloy.

15. The method of claim 12, wherein plastic deformation of the workpiece comprises the forging of multiple high-speed deformation axes, and where the workpiece is cooled comprises high-speed deformation multiple-axis forging as the Workpiece is cooled to the forging temperature of the workpiece in the field of the alpha + beta phase of the titanium alloy.

16. The method of claim 12, wherein plastic deformation of the workpiece comprises the forging by undercuts of the workpiece to a deformation of the workpiece. beta stress in the range of 0.1 to 0.5.

17. The method of claim 1, wherein the forging temperature of the workpiece is in a range of 100 ° F (55.6 ° C) below the beta transus temperature of the titanium alloy up to 700 ° F (388). , 9 ° C) below the beta transus temperature of the titanium alloy.

18. The method of claim 1 further comprises intermediate and successive steps of press forging, which allows the internal region of the adiabatically heated workpiece to be allowed to cool to a temperature equal to or close to the temperature of the forging. the workpiece in the setting temperature range of the workpiece, and heating the external surface of the workpiece to a temperature equal to or close to the setting temperature of the workpiece in the forging range of the workpiece. Workpiece.

19. The method of claim 18, wherein the adiabatic heated internal region of the work piece is allowed to cool for a cooling time of the inner region in the range of 5 seconds to 120 seconds.

20. The method of claim 18, wherein heating the external surface of the workpiece comprises heating using one or more of flame heating, box-furnace heating, induction heating and radiant heating.

21. The method of claim 18, wherein the dies of a forge used to forge the work piece are heated to a temperature in a range from the forging temperature of the workpiece to 100 ° F (55.6 ° C) below of the forging temperature of the work piece.

22. The method of claim 1, wherein after a total deformation of at least 1.0 is achieved, the workpiece comprises an average alpha particle grain size in the range of 4 mm or less.

23. The method of claim 1, wherein repeating at least one of the forging stages with press until a total deformation of at least 1.0 is achieved in the workpiece comprises press forging the workpiece at a second temperature of forging the work piece, where the second forging temperature of the workpiece is within the alpha-beta phase field of the titanium alloy of the workpiece, and where the second forging temperature of the workpiece is less than the temperature for forging the work piece.

24. A method for refining the grain size of a workpiece comprising a titanium alloy, the method comprises: subject the workpiece to beta annealing - cool the work piece subjected to beta annealing at a temperature below the beta transus temperature of the titanium alloy; Y Forging the workpiece with multiple axes, where the forging of multiple axes comprises the forging with press at a forging temperature of the workpiece in a temperature range of forging the workpiece in the direction of a first axis A orthogonal to the workpiece up to a height of spacer of considerable reduction with a deformation speed that is sufficient to heat, adiabatically, an internal region of the workpiece, forging the workpiece with the press at the forging temperature of the workpiece in the direction of a second orthogonal axis B of the workpiece with respect to a first height of the blocking reduction spacer, forging the work piece with the press at the forging temperature of the work piece in the direction of a third orthogonal axis C of the workpiece with respect to a second height of the blocking reduction spacer, forging the work piece with the press at the forging temperature of the workpiece in the direction of the second orthogonal axis B of the workpiece up to the height of the considerable reduction spacer with a deformation speed which is sufficient to heat, of adiabatic form, an internal region of the work piece, forging the work piece with the press at the forging temperature of the workpiece in the direction of the orthogonal third axis C of the workpiece with respect to the first height of the blocking reduction spacer, forging with a press the workpiece at the forging temperature of the workpiece in the direction of the first orthogonal axis A of the workpiece with respect to the second height of the blocking reduction spacer, Forging the work piece with temperature press Forging the workpiece in the direction of the orthogonal third axis C of the workpiece up to the height of the considerable reduction spacer with a deformation speed which is sufficient to heat, adiabatically, an internal region of the work piece. job, forging with a press the workpiece at the forging temperature of the workpiece in the direction of the first orthogonal axis A of the workpiece with respect to the first height of the blocking reduction spacer, forging the workpiece with the press at the forging temperature of the workpiece in the direction of the second orthogonal axis B of the workpiece with respect to the second height of the blocking reduction spacer, and repeat at least one of the preceding press forging stages until a total deformation of at least 1.0 is achieved in the workpiece.

25. The method of claim 24, wherein at least one of the pressing forging steps is repeated until a total deformation of at least 1.0 to less than 3.5 is achieved in the workpiece.

26. The method of claim 24, wherein a speed of The deformation used during pressing forging is in the range of 0.2 s1 to 0.8 s1.

27. The method of claim 24, wherein the workpiece comprises one of an alpha + beta titanium alloy and a metastable beta titanium alloy.

28. The method of claim 24, wherein the workpiece comprises an alpha + beta titanium alloy.

29. The method of claim 27 or 28, wherein the titanium alloy comprises at least one of alloy additions of grain fixation and beta stabilization content to decrease the alpha phase precipitation and the kinetics of alpha phase growth.

30. The method of claim 24, wherein the workpiece comprises a titanium alloy that is selected from the alloy Ti-6AI-2Sn-4Zr-6Mo (UNS R56260), the alloy Ti-6AI-2Sn-4Zr-2Mo-0.08 Yes (UNS R54620), the Ti-4AI-2.5V alloy (UNS R54250), the Ti-6AI-7Nb alloy (UNS R56700) and the Ti-6AI-6V-2Sn alloy (UNS R56620).

31. The method of claim 24, wherein cooling the workpiece subjected to beta annealing comprises cooling the workpiece to room temperature.

32. The method of claim 24, wherein cooling the workpiece subjected to beta annealing comprises cooling the workpiece to the forging temperature of the workpiece.

33. The method of claim 24, wherein the annealing of the workpiece comprises heating the workpiece to a beta annealing temperature in a beta transus temperature range of the titanium alloy up to 300 ° F (111 ° C) on the beta transus temperature of the titanium alloy.

34. The method of claim 24, wherein the beta annealing of the workpiece comprises heating the workpiece to a beta annealing temperature for a time in the range of 5 minutes to 24 hours.

35. The method of claim 24, further comprising plasticly deforming the workpiece to a plastic deformation temperature in the beta phase field of the titanium alloy before cooling the work piece subjected to beta annealing to a temperature below the beta transus temperature of the titanium alloy.

36. The method of claim 35, wherein plastic deformation of the workpiece at a plastic deformation temperature in the beta-phase field of the titanium alloy comprises at least one extrusion, reinforcement forging, and multiple forging. deformation high-speed axis in the workpiece.

37. The method of claim 35, wherein the temperature of the plastic deformation lies in a range of the beta transus temperature of the titanium alloy of the workpiece up to 300 ° F (111 ° C) above the beta transus temperature of the titanium alloy of the work piece.

38. The method of claim 35, wherein plastic deformation of the workpiece comprises the forging of multiple axes of high deformation speed, and where to cool the workpiece subjected to beta annealing It comprises the multi-axis forging of high-speed deformation as the workpiece is cooled to the forging temperature of the workpiece in the field of the alpha + beta phase of the titanium alloy.

39. The method of claim 35, wherein plastic deformation of the workpiece comprises forging the work piece to undergo a bending deformation beta in the range of 0.1 to 0.5.

40. The method of claim 24, wherein the forging temperature of the workpiece is in a range of 100 ° F (55.6 ° C) below the beta transus temperature of the titanium alloy up to 700 ° F (388). ° C) below the beta transus temperature of the titanium alloy.

41. The method of claim 24, wherein the successive intermediate stages of forging with press, the internal region of the work piece heated adiabatically is allowed to cool to a temperature equal to or close to the setting temperature of the workpiece in the Forging temperature range of the workpiece, and the outer surface region of the workpiece is heated to a temperature equal to or close to the setting temperature of the workpiece in the forging range of the workpiece.

42. The method of claim 41, wherein the internal region adiabatically heated of the work piece is allowed to cool for a time in the range of 5 seconds to 120 seconds.

43. The method of claim 41, wherein heating the external surface of the workpiece comprises heating using one or more of flame heating, box-furnace heating, induction heating and radiant heating.

44. The method of claim 41, wherein the dies of a forge used to forge the work piece are heated to a temperature in a range from the forging temperature of the workpiece to 100 ° F (55.6 ° C) below of the forging temperature of the work piece.

45. The method of claim 24, wherein after that achieves a total deformation of at least 1.0, the workpiece comprises an average alpha particle grain size of 4 mm or less.

46. The method of claim 24, wherein repeating at least one of the pressing forging stages until a total deformation of at least 1.0 is achieved in the workpiece comprises crimping the workpiece at a second temperature of the workpiece. forging of the workpiece, where the second forging temperature of the workpiece is within the alpha-beta phase field of the titanium alloy workpiece, and where the second forging temperature of the workpiece work is less than the forging temperature of the work piece. SUMMARY Methods for refining the grain size of a titanium alloy workpiece include beta-annealing the workpiece, cooling the workpiece subjected to beta annealing at a temperature lower than the transus ion temperature of the titanium alloy , and forge with multiple axes at high deformation speed the workpiece. The forging of multiple axes at high speed of deformation is used until achieving a total deformation of at least 1 in the workpiece of titanium alloy, or until a total deformation of at least 1 to 3.5 is achieved in the piece working titanium alloy. The titanium alloy of the workpiece may comprise at least one addition of alloys of grain fixation and beta stabilization content effective to decrease phase precipitation and alpha growth kinetics.