Methods of beta processing titanium alloys

• US 7,611,592 B2
• Filed: 02/23/2006
• Issued: 11/03/2009
• Est. Priority Date: 02/23/2006
• Status: Active Grant

• Current Assignee: ATI Properties Incorporated (Allegheny Technologies Incorporated)
• Original Assignee: ATI Properties Incorporated (Allegheny Technologies Incorporated)
• Inventors: Davis, R. Mark, Arnold, Matthew J.
• Primary Examiner(s): Wyszomierski; George
• Assistant Examiner(s): Shevin; Mark L
• Application Number:
  US11/360,065
• Publication Number:
  US 20070193018A1
• Time in Patent Office: 1,349 Days
• Field of Search: 295/271, 295/275, 295/277, 148669-671, 148/421, 420417-421
• US Class Current: 148/671
• CPC Class Codes: B21B 1/46 for rolling metal immediately subsequent to continuous casting metal-rolling stands B21B13/22; continuous casting B22D11/00, e.g. into moulds with rolls B22D11/06
• CPC Class Codes: B21B 3/00 Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metalsaltering special metallurgical properties of alloys, other than structure consolidation or mechanical properties resulting therefrom C21D, C22F
• CPC Class Codes: C22C 14/00 Alloys based on titanium
• CPC Class Codes: C22F 1/183 of titanium or alloys based thereon
• CPC Class Codes: Y10T 29/4998 Combined manufacture including applying or shaping of fluent material
• CPC Class Codes: Y10T 29/49988 Metal casting
• CPC Class Codes: Y10T 29/49991 Combined with rolling

Abstract

Various non-limiting embodiments of the present invention relate to methods of processing titanium alloys wherein the alloys are subjected to deformation above the beta transus temperature (T_β) of the alloys. For example, one non-limiting embodiment provides a method of processing an alpha+beta or a near-beta titanium alloy comprising deforming a body of the alloy at a first temperature (T₁) that is above the T_β of the alloy; recrystallizing at least a portion of the alloy by deforming and/or holding the body at a second temperature (T₂) that is greater than T₁; and deforming the body at a third temperature (T₃), wherein T₁≧T₃>T_β; wherein essentially no deformation of the body occurs at a temperature below T_β during the method of processing the titanium alloy.

Claims

1. A method of processing a titanium alloy comprising:

deforming a body of a titanium alloy at a first temperature (T₁) that is above the beta-transus temperature (T_β

) of the titanium alloy;

at least one of;

(i) deforming the body at a second temperature (T₂), wherein T₂ is at least 50°

F. greater than T₁ to recrystallize at least a portion of the titanium alloy, or (ii) holding the body at T₂ for a time period sufficient to recrystallize at least a portion of the titanium alloy; and

deforming the body at a third temperature (T₃), wherein T₁≧

T₃>

T_β

;

wherein the titanium alloy is one of an alpha+beta alloy and a near-beta alloy, and

wherein essentially no deformation of the body occurs at a temperature below T_β

during the method of processing the titanium alloy.

2. The method of claim 1 wherein the titanium alloy is an alpha+beta alloy.

3. The method of claim 2 wherein the alpha+beta titanium alloy is Ti-6Al-4V.

4. The method of claim 1 wherein the titanium alloy is a near-beta titanium alloy.

5. The method of claim 4 wherein the near-beta titanium alloy is one of Ti-5Al-2Sn-2Zr-4Mo-4Cr, Ti-6Al-2Sn-2Zr-2Cr-2Mo-0.15Si, and Ti-4.5Al-3V-2Mo-2Fe.

6. The method of claim 1 wherein the body is a homogenized cast ingot.

7. The method of claim 1 wherein deforming the body at T₁ includes at least one of forging, cogging, extrusion, drawing and rolling.

8. The method of claim 1 wherein deforming the body at T₁ comprises deforming the body at T₁ to attain a total percent reduction in cross- sectional area of at least 15 percent during deformation at T₁.

9. The method of claim 1 wherein deforming the body at T₁ comprises deforming the body at T₁ to attain a total percent reduction in cross-sectional area ranging from 20 percent to 70 percent during deformation at T₁.

10. The method of claim 1 wherein deforming the body at T₁ comprises deforming the body at T₁ to attain a total percent reduction in cross-sectional area ranging from 25 percent to 65 percent during deformation at T₁.

11. The method of claim 1 wherein T₁ is at least 50°

F. greater than T_β

.

12. The method of claim 1 wherein T₁ ranges from 50°

F. greater than T_β

to 800°

F. greater than T_β

.

13. The method of claim 1 further comprising cooling the body to a temperature below T_β

of the titanium alloy after deforming at T₁ and prior to at least one of deforming the body at T₂ or holding the body at T₂.

14. The method of claim 1 wherein T₂ ranges from T₁+50°

F. to T₁+800°

F.

15. The method of claim 1 wherein T₂ ranges from T₁+75°

F. to T₁+500°

F.

16. The method of claim 1 wherein T₂ ranges from T₁+100°

F. to T₁+200°

F.

17. The method of claim 1 wherein T₂ is at least T₁+150°

F.

18. The method of claim 1 wherein prior to deforming the body at T₃, the body is subjected to at least two cycles of deforming the body at T₁ and deforming or holding the body at T₂, wherein for each of the at least two cycles T₁ is independently chosen and ranges from T_β

+50°

F. to T_β

+800°

F. and T₂ is independently chosen and ranges from T₁+50°

F. to T₁+800°

F.

19. The method of claim 1 wherein prior to deforming the body at T₃, the body is cooled from T₂ to a temperature below T_β

of the titanium alloy and is subsequently heated at T₃.

20. The method of claim 1 wherein deforming the body at T₃ comprises forging the body.

21. The method of claim 1 wherein deforming the body at T₃ comprises deforming the body at T₃ to attain a total percent reduction in cross-sectional area of at least 15 percent during deformation at T₃.

22. The method of claim 1 wherein deforming the body at T₃ comprises deforming the body at T₃ to attain a total percent reduction in cross-sectional area ranging from 20 percent to 70 percent during deformation at T₃.

23. The method of claim 1 wherein deforming the body at T₃ comprises deforming the body at T₃ to attain a total percent reduction in cross-sectional area ranging from 25 percent to 65 percent during deformation at T₃.

24. The method of claim 1 wherein T₃ is at least 50°

F. greater than T_β

.

25. The method of claim 1 wherein T₃ ranges from 50°

F. greater than T_β

to 800°

F. greater than T_β

.

26. The method of claim 1 wherein after deforming the body at T₃ the alloy is cooled to an ambient temperature by at least one of air cooling, forced air cooling and liquid quenching.

27. The method of claim 1 wherein after conducting the method of processing, the body is essentially free of strain induced porosity.

28. A method of processing an alpha+beta or a near-beta titanium alloy, the method comprising:

deforming the titanium alloy at a first temperature (T₁) that is above the beta-transus temperature (T_β

) of the titanium alloy;

recrystallizing at least a portion of the titanium alloy by at least one of deforming or holding the titanium alloy at a temperature that is at least 50°

F. greater than T₁;

deforming the titanium alloy at a temperature ranging from greater than T_β

up to T₁; and

cooling the titanium alloy to a temperature below T_β

without deforming the titanium alloy during cooling;

wherein between the steps of deforming the titanium alloy at T₁ and cooling the titanium alloy to a temperature below T_β

, deformation of the titanium alloy occurs only at temperatures above T_β

.

29. A method of processing an ingot of a titanium alloy, the method comprising:

heating the ingot until at least a portion of the ingot attains a first temperature that is at least 50°

F. above the beta-transus temperature (T_β

) of the titanium alloy;

deforming the ingot at T₁ to attain a total percent reduction in cross-sectional area of at least 15 percent during deformation at T₁;

heating the ingot until at least a portion of the ingot attains a second temperature (T₂) that is at least 50°

F. greater than T₁;

at least one of (i) deforming the body at T₂ to recrystallize at least a portion of the titanium alloy, and (ii) holding the ingot at T₂ for a time period sufficient to recrystallize at least a portion of the titanium alloy;

allowing at least a portion of the ingot to attain a third temperature (T₃), wherein T₁≧

T₃>

T_β

; and

deforming the ingot at T₃ to attain a total percent reduction in cross-sectional area of at least 15 percent during deformation at T₃,

wherein the titanium alloy is one of an alpha+beta titanium alloy and a near-beta titanium alloy, and wherein between the steps of deforming the ingot at T₁ and deforming the ingot at T₃, essentially no deformation of the ingot occurs at a temperature below T_β

.

30. The method of claim 29 wherein subsequent to deforming the ingot at T₃, the ingot is cooled to a temperature below T_β

and deformed to attain a total percent reduction in cross-sectional area of no greater than 25 percent.