METHOD OF FORMING A STAMPED ARTICLE

• US 20130020000A1
• Filed: 07/20/2011
• Published: 01/24/2013
• Est. Priority Date: 07/20/2011
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Carter, Jon T.
• Granted Patent: US 9,279,167 B2
• Time in Patent Office: Days
• US Class Current: 148/714
• CPC Class Codes: B21D 22/208 by heating the blank or deep-drawing associated with heat treatment C21D takes precedence
• CPC Class Codes: C21D 1/06 Surface hardening
• CPC Class Codes: C21D 9/48 deep-drawing sheets

Abstract

A method of forming an article from a metal alloy sheet material includes selectively hardening only a first localized area of the metal alloy sheet material without hardening a second localized area of the metal alloy sheet material, wherein the second area adjoins the first area to thereby form a blank. The blank has a hardened region formed from the first area and having a first hardness, and a non-hardened region adjoining the hardened region and formed from the second area, and having a second hardness that is less than the first hardness. The method includes stamping the blank to thereby form a preform having a pre-protrusion at least partially formed from the hardened region, wherein the pre-protrusion has a first height, annealing the preform to thereby form a workpiece, and stamping the workpiece to increase the first height and thereby form the article.

Claims

1. A method of forming an article from a metal alloy sheet material, the method comprising:

selectively hardening only a first localized area of the metal alloy sheet material without hardening a second localized area of the metal alloy sheet material, wherein the second localized area adjoins the first localized area, to thereby form a blank having;

a hardened region formed from the first localized area and having a first hardness; and

a non-hardened region adjoining the hardened region and formed from the second localized area, wherein the non-hardened region has a second hardness that is less than the first hardness;

stamping the blank to thereby form a preform having a pre-protrusion at least partially formed from the hardened region, wherein the pre-protrusion has a first height;

annealing the preform to thereby form a workpiece; and

stamping the workpiece to increase the first height and thereby form the article.

2. The method of claim 1, further including, concurrent to stamping the blank, preferentially inducing greater deformation of the blank at the non-hardened region than at the hardened region.

3. The method of claim 1, further including, concurrent to stamping the workpiece, preferentially inducing greater deformation of the workpiece at the hardened region than at the non-hardened region.

4. The method of claim 3, wherein stamping the workpiece includes elongating both of the hardened region and the non-hardened region to increase the first height.

5. The method of claim 1, further including, concurrently increasing the first height and minimizing localized tearing of the workpiece at the pre-protrusion.

6. The method of claim 1, further including, concurrent to stamping the blank, increasing the first hardness to a third hardness, and increasing the second hardness to a fourth hardness.

7. The method of claim 6, further including, after stamping the blank, decreasing the third hardness.

8. The method of claim 1, wherein the hardened region and the non-hardened region cooperate to increase the first height and thereby form the article.

9. The method of claim 1, wherein the hardened region has a maximized localized thickness after stamping the blank.

10. The method of claim 1, further including selecting the first localized area according to a desired location of the pre-protrusion on the preform.

11. The method of claim 1, wherein selectively hardening includes annealing the second localized area without annealing the first localized area.

12. The method of claim 1, wherein selectively hardening includes deforming the first localized area without deforming the second localized area.

13. The method of claim 1, wherein selectively hardening includes heating the first localized area without heating the second localized area.

14. The method of claim 1, wherein annealing includes heating the preform to a temperature of from about 250°

C. to about 550°

C.

15. The method of claim 1, wherein the metal alloy sheet material is an age-hardenable metal alloy in sheet form.

16. The method of claim 1, wherein the metal alloy sheet material is a strain-hardenable metal alloy in sheet form.

17. A method of forming an article from a metal alloy sheet material, the method comprising:

selectively hardening only a plurality of first localized areas of the metal alloy sheet material without hardening a plurality of second localized areas of the metal alloy sheet material, wherein each of the plurality of second localized areas adjoins a respective one of the plurality of first localized areas, to thereby form a blank having;

a plurality of hardened regions each formed from a respective one of the plurality of first localized areas, wherein each of the plurality of hardened regions has a first hardness; and

a plurality of non-hardened regions each adjoining a respective one of the plurality of hardened regions and formed from a respective one of the plurality of second localized areas, wherein each of the plurality of non-hardened regions has a second hardness that is less than the first hardness;

stamping the blank to thereby form a preform having a plurality of pre-protrusions each at least partially formed from a respective one of the plurality of hardened regions, wherein each of the plurality of pre-protrusions has a first height;

concurrent to stamping the blank, preferentially inducing greater deformation of the blank at each of the plurality of non-hardened regions than at each of the plurality of hardened regions and thereby increasing the first hardness to a third hardness, and increasing the second hardness to a fourth hardness;

after stamping the blank, annealing the preform to thereby decrease the third hardness and the fourth hardness and form a workpiece;

stamping the workpiece to elongate both of the plurality of hardened regions and the plurality of non-hardened regions to thereby increase the first height and form the article, wherein the article has a plurality of protrusions each formed from a respective one of the plurality of pre-protrusions and having a second height that is greater than the first height; and

concurrent to stamping the workpiece, preferentially inducing greater deformation of the workpiece at each of the plurality of hardened regions than at each of the plurality of non-hardened regions, wherein each of the plurality of hardened regions cooperates with a respective one of the plurality of non-hardened regions to increase the first height to the second height and thereby form the article.

18. The method of claim 17, wherein stamping the workpiece forms the article having a substantially uniform thickness of from about 0.75 mm to about 2.25 mm at each of the plurality of protrusions.

19. A method of forming an article from a metal alloy sheet material, the method comprising:

selectively hardening only a plurality of first localized areas of the metal alloy sheet material without hardening any of a plurality of second localized areas of the metal alloy sheet material, wherein each of the plurality of second localized areas adjoins a respective one of the plurality of first localized areas, or a remainder of the metal alloy sheet material, wherein the remainder excludes the plurality of first localized areas and the plurality of second localized areas, to thereby form a blank having;

a plurality of hardened regions each formed from a respective one of the plurality of first localized areas, wherein each of the plurality of hardened regions has a first hardness; and

a plurality of non-hardened regions each adjoining a respective one of the plurality of hardened regions and formed from a respective one of the plurality of second localized areas, wherein each of the plurality of non-hardened regions has a second hardness that is less than the first hardness;

stamping the blank to thereby form a preform having a plurality of pre-protrusions each at least partially formed from a respective one of the plurality of hardened regions, wherein each of the plurality of pre-protrusions has a first height;

selectively annealing each of the plurality of pre-protrusions without annealing the remainder to thereby form a workpiece; and

stamping the workpiece to increase the first height and thereby form the article.

20. The method of claim 19, wherein selectively annealing includes induction heating each of the plurality of pre-protrusions to a temperature of from about 300°

C. to about 500°

C. for a duration of from about 5 seconds to about 1 minute.