CoCr alloys and methods for making same

• US 20050155679A1
• Filed: 04/09/2003
• Published: 07/21/2005
• Est. Priority Date: 04/09/2003
• Status: Abandoned Application

• Current Assignee: Coastcast Corporation SA, Gainsmart Group Limited, Guinsmart Group Limited, Precison Metal Products, Inc.
• Original Assignee: Coastcast Corporation SA, Precision Metal Products Incorporated (HBD Industries Incorporated)
• Inventors: Nootens, Steve, Wyte, Michael
• Application Number:
  US10/410,895
• Publication Number:
  US 20050155679A1
• Time in Patent Office: Days
• US Class Current: 148/557
• CPC Class Codes: B22D 21/025 Casting heavy metals with high melting point, i.e. 1000 - 1600 degrees C, e.g. Co 1490 degrees C, Ni 1450 degrees C, Mn 1240 degrees C, Cu 1083 degrees C
• CPC Class Codes: C22C 1/02 by melting C22C1/1036 takes precedence
• CPC Class Codes: C22C 19/07 based on cobalt
• CPC Class Codes: C22F 1/10 of nickel or cobalt or alloys based thereon

Abstract

A method of producing a forged part is described. The method includes the steps of: preparing an ingot consisting essentially of:

ElementWeight PercentC0.00-0.35Si0.00-1.00Cr26.00-30.00Mo5.00-7.00Ni0.00-1.00Fe0.00-0.75Mn0.00-1.00N0.00-0.25CoBalance(b) determining the ingot melting temperature; (c) determining the pouring temperature; (d) minimizing the difference between the pouring temperature and the mold temperature to no more than about 100° F.; (e) designing an investment casting preform geometry to achieve uniform reduction in all sections of the part; (f) preparing an investment mold; (g) molding the part by casting; (h) placing the part in a forging die; (i) subjecting the part to one or more forging hits at a forging preheat of between about 1700° F. and about 1800° F. to achieve a reduction of about 15% to about 20%; (j) vacuum annealing the part at between about 1800° F. and about 2400° F. for about 30 minutes to about 8 hours under a partial pressure of argon; (k) quenching the part to below about 1400° F. in about 5 minutes or less under a minimum of about 5 bars of argon; and (l) subjecting the part to one or more forging hits at between about 1200° F. and about 2200° F. to achieve a final about 3% to about 60% of reduction. The pouring temperature is preferably no more than about 100° F. from the ingot melting temperature. The investment mold has one or more gates. The forging die is designed to match the preform geometry to facilitate homogeneous percentage reduction in all areas and section thicknesses of the part.

Claims

1. A method for producing a forged part, the method comprising the steps of:

(a) providing an ingot having a chemistry that meets the chemical requirements of ASTM forging and casting specifications;

(b) casting the ingot into a preform by molding; and

(c) subjecting the cast preform to one or more hot forging hits, thereby forming the part.

2. The method of claim 1 further comprising the step of subjecting the part to a thermal process after step (c).

3. The method of claim 2 further comprising the step of subjecting the part to one or more forging hits after subjecting the part to the thermal process.

4. The method of claim 3 further comprising the step of developing a casting preform geometry.

5. The method of claim 4 further comprising the step of developing a casting mold configuration.

6. The method of claim 5 further comprising the step of establishing casting parameters including mold and ingot melt temperatures.

7. The method of claim 2 wherein the thermal process is an annealing process.

8. The method of claim 1 wherein the ingot consists essentially of:

9. The method of claim 8 wherein the ingot further comprises

10. The method of claim 8 wherein the ingot further comprises

11. The method of claim 1 wherein step (c) further comprises the step of using a specially designed die to achieve approximately 90% of the metal movement required to meet the final product dimension and impart both the required grain structure and physical properties for the part.

12. The method of claim 1 wherein the ingot consists essentially of:

13. The method of claim 12 wherein the ingot further comprises

14. The method of claim 12 wherein the ingot further comprises

15. The method of claim 1 wherein the one or more hot forging hits are done at a temperature between about 1200°

F. and about 2200°

F.

16. The method of claim 1 wherein the one or more hot forging hits are done at a temperature between about 1700°

F. and about 1800°

F.

17. The method of claim 7 wherein the annealing process comprises vacuum annealing at between about 1800°

F. and about 2400°

F. for between about 30 minutes to about 8 hours under a partial pressure of argon.

18. The method of claim 7 wherein the annealing process comprises vacuum annealing at between about 2005°

F. and about 2235°

F. for between about 3 hours and 45 minutes and 4 hours and 15 minutes under a partial pressure of argon.

19. The method of claim 3 wherein the one or more hot forging hits are done at a temperature between about 1200°

F. and about 2200°

F.

20. The method of claim 1 wherein the forged part meets the requirements of ASTM F-799 and ASTM F-1537 for warm worked product.

21. The method of claim 6 wherein the casting parameters further include pouring temperature, and wherein the pouring temperature is no more than about 100°

F. from the ingot melting temperature.

22. The method of claim 21 wherein the pouring temperature is between about 20°

F. and 100°

F. from the ingot melting temperature.

23. The method of claim 21 wherein the pouring temperature is between about 75°

F. and about 80°

F. from the ingot melting temperature.

24. The method of claim 21 wherein the difference between the pouring temperature and the mold temperature is no more than 100°

F.

25. The method of claim 24 wherein the difference between the pouring temperature and the mold temperature is (about 2150°

F.±

about 25°

F.)−

(ingot melting temperature+about 80°

F.±

about 20°

F.).

26. The method of claim 24 wherein the difference between the pouring temperature and the mold temperature is (between about 2150°

F. to 2500°

F.)−

(ingot melting temperature+about 80°

F.±

about 20°

F.).

27. The method of claim 1 wherein the cast preform is subject to a single hot forging hit.

28. The method of claim 3 wherein the part is subject to a single forging hit after it is subject to the thermal process.

29. The method of claim 3 wherein the cast preform is subject to a single hot forging hit, and wherein the part is subject to a single forging hit after it is subject to the thermal process.

30. An alloy consisting essentially of:

31. The alloy of claim 30 further comprising:

32. The alloy of claim 30 further comprising:

33. An alloy consisting essentially of:

34. The alloy of claim 33 further comprising:

35. The alloy of claim 33 further comprising:

36. An alloy consisting essentially of

37. The alloy of claim 36 further comprising:

38. The alloy of claim 36 further comprising:

39. An alloy consisting essentially of:

40. The alloy of claim 39 further comprising:

41. The alloy of claim 39 further comprising:

42. An alloy consisting essentially of:

43. The alloy of claim 42 further comprising:

44. The alloy of claim 42 further comprising:

45. An alloy consisting essentially of:

46. The alloy of claim 45 further comprising:

47. The alloy of claim 45 further comprising:

48. A surgical implant produced by casting and forging, wherein the implant meets the mechanical property and microstructural requirements of ASTM F-799 and ASTM F-1537.

49. The surgical implant of claim 48, wherein the implant is a hip stem.

50. A method of producing a forging, the method comprising the steps of:

(a) casting a material having a predetermined shape; and

(b) forging the material to produce a product,

wherein the product meets the mechanical property and microstructural requirements of ASTM F-799 and ASTM F-1537.

51. The method of claim 50 wherein the product is a surgical implant.

52. The method of claim 51 wherein the surgical implant is a hip stem.

53. A method of producing a forged part, the method comprising the steps of:

(a) preparing an ingot consisting essentially of;

ElementWeight PercentC0.00-0.14Si0.00-1.00Cr26.00-30.00Mo5.00-7.00Ni0.00-1.00Fe0.00-0.75Mn0.00-1.00N0.00-0.25CoBalance

(b) determining the ingot melting temperature;

(c) determining the pouring temperature, wherein the pouring temperature is no more than about 100°

F. from the ingot melting temperature;

(d) minimizing the difference between the pouring temperature and the mold temperature to no more than about 100°

F.;

(e) designing an investment casting preform geometry to achieve uniform reduction in all sections of the part;

(f) preparing an investment mold, wherein the investment mold has one or more gates;

(g) molding the part by casting;

(h) placing the part in a forging die, wherein the forging die is designed to match the preform geometry to facilitate homogeneous percentage reduction in all areas and section thicknesses of the part;

(i) subjecting the part to one or more forging hits at a forging preheat of between about 1700°

F. and about 1800°

F. to achieve a reduction of about 15% to about 20%;

(j) vacuum annealing the part at between about 1800°

F. and about 2400°

F. for about 30 minutes to about 8 hours under a partial pressure of argon;

(k) quenching the part to below about 1400°

F. in about 5 minutes or less under a minimum of about 5 bars of argon; and

(l) subjecting the part to one or more forging hits at between about 1200°

F. and about 1500°

F. to achieve a final about 5% of reduction.

54. The method of claim 53 wherein the part meets the grain size requirements of ASTM F-799 and ASTM F-1537 for warm worked product.

55. The method of claim 53 wherein the ingot further comprises:

56. The method of claim 53 wherein the ingot further comprises:

57. The method of claim 53 wherein the investment mold has a single gate.

58. A forging produced by the following method:

(a) preparing an ingot consisting essentially of

ElementWeight PercentC0.21-0.35Si0.00-1.00Cr27.00-30.00Mo5.00-7.00Ni0.00-1.00Fe0.00-0.75Mn0.00-1.00N0.00-0.25CoBAL

(b) determining the ingot melting temperature;

(c) determining the pouring temperature, wherein the pouring temperature is no more than about 100°

F. from the ingot melting temperature;

(d) minimizing the difference between the pouring temperature and the mold temperature to no more than about 100°

F.;

(e) designing an investment casting preform geometry to achieve uniform reduction in all sections of the part;

(f) preparing an investment mold, wherein the investment mold has one or more gates;

(g) molding the part by casting;

(h) placing the part in a forging die, wherein the forging die is designed to match the preform geometry to facilitate homogeneous percentage reduction in all areas and section thicknesses of the part;

(i) subjecting the part to one or more forging hits at a forging preheat of between about 1700°

F. and about 1800°

F. to achieve a reduction of about 15% to about 20%;

(j) vacuum annealing the part at between about 1800°

F. and about 2400°

F. for about 30 minutes to about 8 hours under a partial pressure of argon;

(k) quenching the part to below about 1400°

F. in about 5 minutes or less under a minimum of about 5 bars of argon; and

(l) subjecting the part to one or more forging hits at between about 1200°

F. and about 1500°

F. to achieve a final about 5% of reduction.

59. The forging of claim 58 wherein the part meets the grain size requirements of ASTM F-799 and ASTM F-1537 for warm worked product.

60. The forging of claim 58 wherein the ingot further comprises:

61. The forging of claim 58 wherein the ingot further comprises:

62. The forging of claim 58 wherein the investment mold has a single gate.

63. A forged part consisting essentially of

64. The forged part of claim 63, wherein the forged part is a surgical implant.