Thermomechanical processing of high strength non-magnetic corrosion resistant material

• US 9,192,981 B2
• Filed: 03/11/2013
• Issued: 11/24/2015
• Est. Priority Date: 03/11/2013
• Status: Active Grant

• Current Assignee: ATI Properties LLC (CNH Industrial N.V.)
• Original Assignee: ATI Properties Incorporated (Allegheny Technologies Incorporated)
• Inventors: Forbes Jones, Robin M., Smith, George J. Jr., Floder, Jason P., Thomas, Jean-Philippe A., Minisandram, Ramesh S.
• Primary Examiner(s): TOLAN, EDWARD THOMAS
• Application Number:
  US13/792,285
• Publication Number:
  US 20140255719A1
• Time in Patent Office: 988 Days
• Field of Search: 723/56, 727/00
• US Class Current: 1/1
• CPC Class Codes: B21J 1/02 Preliminary treatment of metal stock without particular shaping, e.g. salvaging segregated zones, forging or pressing in the rough modifying the physical properties by deformation C21D7/00, C22F1/00
• CPC Class Codes: B21J 1/04 Shaping in the rough solely by forging or pressing
• CPC Class Codes: B21J 5/022 Open die forging
• CPC Class Codes: B21J 5/08 Upsetting
• CPC Class Codes: B21J 7/14 Forging machines working with several hammers
• CPC Class Codes: C21D 6/004 containing Cr and Ni
• CPC Class Codes: C21D 7/13 by hot working
• CPC Class Codes: C21D 8/005 of ferrous alloys C21D8/02 - C21D8/12 take precedence
• CPC Class Codes: C22C 38/001 containing N
• CPC Class Codes: C22C 38/002 containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
• CPC Class Codes: C22C 38/02 containing silicon
• CPC Class Codes: C22C 38/06 containing aluminium
• CPC Class Codes: C22C 38/42 with copper
• CPC Class Codes: C22C 38/44 with molybdenum or tungsten
• CPC Class Codes: C22C 38/46 with vanadium
• CPC Class Codes: C22C 38/48 with niobium or tantalum
• CPC Class Codes: C22C 38/50 with titanium or zirconium
• CPC Class Codes: C22C 38/52 with cobalt
• CPC Class Codes: C22C 38/54 with boron
• CPC Class Codes: C22C 38/58 with more than 1.5% by weight of manganese
• CPC Class Codes: Y10T 428/1241 : Nonplanar uniform thickness or nonlinear uniform diameter [e.g., L-shape]

Abstract

A method of processing a non-magnetic alloy workpiece comprises heating the workpiece to a warm working temperature, open die press forging the workpiece to impart a desired strain in a central region of the workpiece, and radial forging the workpiece to impart a desired strain in a surface region of the workpiece. In a non-limiting embodiment, after the steps of open die press forging and radial forging, the strain imparted in the surface region is substantially equivalent to the strain imparted in the central region. In another non-limiting embodiment, the strain imparted in the central and surface regions are in a range from 0.3 inch/inch to 1 inch/inch, and there exists no more than a 0.5 inch/inch difference in strain of the central region compared with the strain of the surface region of the workpiece. An alloy forging processed according to methods described herein also is disclosed.

Claims

1. A method of processing a non-magnetic alloy workpiece, comprising:

heating the workpiece to a warm working temperature;

open the press forging the workpiece to impart a desired strain to a central region of the workpiece; and

radial forging the workpiece to impart a desired strain to a surface region of the workpiece;

wherein after the open die press forging and the radial forging, the strain imparted to the central region and the strain imparted to the surface region are each in a range of from 0.3 inch/inch to 1.0 inch/inch;

wherein a difference in strain from the central region to the surface region is not more than 0.5 inch/inch.

2. The method of claim 1, wherein after the open die press forging and the radial forging, the strain imparted to the central region and the strain imparted to the surface region are each in a range of from 0.3 inch/inch to 0.8 inch/inch.

3. The method of claim 1, wherein after the open the press forging and the radial forging, the strain imparted to the surface region is substantially equivalent to the strain imparted to the central region.

4. The method of claim 1, wherein the open the press forging precedes the radial forging.

5. The method of claim 1, wherein the radial forging precedes the open the press forging.

6. The method of claim 1, wherein the warm working temperature is in a range spanning a temperature that is one-third of an incipient melting temperature of the non-magnetic ahoy up to a temperature that is two-thirds of an incipient melting temperature of the non-magnetic ahoy.

7. The method of claim 1, wherein the warm working temperature comprises any temperature up to the highest temperature at which recrystallization (dynamic or static) does not occur in the non-magnetic ahoy.

8. The method of claim 1, wherein the non-magnetic ahoy comprises one of a non-magnetic stainless steel alloy, a nickel ahoy, a cobalt alloy, and an iron alloy.

9. The method of claim 1, wherein the non-magnetic alloy comprises a non-magnetic austenitic stainless steel alloy.

10. The method of claim 9, wherein the warm working temperature is from 950°

F. to 1150°

F.

11. The method of claim 1, further comprising, prior to heating the workpiece to the warm working temperature, annealing the workpiece.

12. The method of claim 11, wherein the workpiece comprises a non-magnetic stainless steel alloy;

and annealing the workpiece comprises heating the workpiece at 1850°

F. to 2300°

F. for 1 minute to 10 hours.

13. The method of claim 11, wherein the heating the workpiece to the warm working temperature further comprises allowing the workpiece to cool from an annealing temperature to the warm working temperature.

14. The method of claim 1, wherein the workpiece comprises a circular cross-section.

15. The method of claim 14, wherein the circular cross-section of the workpiece has a diameter greater than 5.25 inches.

16. The method of claim 14, wherein the circular cross-section of the workpiece has a diameter greater than or equal to 7.25 inches.

17. The method of claim 14, wherein the circular cross-section of the workpiece has a diameter in a range of 7.25 inches to 12.0 inches.

18. A method of processing a non-magnetic austenitic stainless steel alloy workpiece, the method comprising:

heating the workpiece to a warm working temperature in the range of 950°

F. to 1150°

F.;

open die press forging the workpiece to impart a final strain of between 0.3 inch/inch to 1.0 inch/inch in a central region of the workpiece; and

radial forging the workpiece to impart a final strain of between 0.3 inch/inch to 1,0 inch/inch in a surface region of the workpiece;

wherein a difference in strain from the central region to the surface region is not more than 0.5 inch/inch.

19. The method of claim 18, wherein:

open the press forging the workpiece imparts a final strain of between 0.3 inch/inch to 0.8 inch/inch in a central region of the workpiece; and

radial forging the workpiece imparts a final strain of between 0.3 inch/inch to 0.8 inch/inch in a surface region of the workpiece.

20. The method of claim 18, wherein the open die press forging precedes the radial forging.

21. The method of claim 18, wherein the radial forging precedes the open die press forging.

22. The method of claim 18, further comprising, prior to heating the workpiece to the warm working temperature, annealing the workpiece.

23. The method of claim 22, wherein annealing the workpiece comprises heating the workpiece at 1850°

F. to 2300°

F. for 1 minute to 10 hours.

24. The method of claim 22, wherein the heating the workpiece to the warm working temperature further comprises allowing the workpiece to cool from the annealing temperature to the warm working temperature.

25. The method of claim 18, wherein the workpiece comprises a circular cross-section.

26. The method of claim 25, wherein the circular cross-section of the workpiece has a diameter of greater than 5.25 inches.

27. The method of claim 25, wherein the circular cross-section of the workpiece has a diameter of greater than or equal to 7.25 inches.

28. The method of claim 25, wherein the circular cross-section of the workpiece has a diameter in a range of 7.25 inches to 12.0 inches.