Advanced case carburizing secondary hardening steels

• US 6,485,582 B1
• Filed: 08/17/2000
• Issued: 11/26/2002
• Est. Priority Date: 01/28/1998
• Status: Expired due to Term

• Current Assignee: Carelyn Campbell, Charles J. Kuehmann, Gregory B. Olson, John P. Wise
• Original Assignee: Carelyn Campbell, Charles J. Kuehmann, Gregory B. Olson, John P. Wise
• Inventors: Kuehmann, Charles J., Olson, Gregory B., Wise, John P., Campbell, Carelyn
• Primary Examiner(s): Yee, Deborah
• Application Number:
  US09/640,612
• Time in Patent Office: 831 Days
• Field of Search: 148/328, 148/336, 148/319, 148/335, 148/326, 420/107, 420/108, 420/109, 420/119, 420/43
• US Class Current: 148/319
• CPC Class Codes: C21D 1/18 Hardening C21D1/02 takes precedence; Quenching with or without subsequent tempering quenching devices C21D1/62
• CPC Class Codes: C21D 2221/10 Differential treatment of inner with respect to outer regions, e.g. core and periphery, respectively
• CPC Class Codes: C21D 6/007 containing Co
• CPC Class Codes: C21D 6/04 Hardening by cooling below 0 degrees Celsius
• CPC Class Codes: C21D 9/32 for gear wheels, worm wheels, or the like
• CPC Class Codes: C22C 38/105 containing Co and Ni
• CPC Class Codes: C22C 38/44 with molybdenum or tungsten
• CPC Class Codes: C22C 38/46 with vanadium
• CPC Class Codes: C22C 38/52 with cobalt
• CPC Class Codes: F16H 55/06 Use of materials; Use of treatments of toothed members or worms to affect their intrinsic material properties coatings for lubrication F16H57/041; producing gear wheels from plastics or substances in a plastic state B29D15/00; heat treatment C21D9/32; electrolytic surface treatment C25D; heating by electromagnetic field H05B6/00

Abstract

Steel alloys susceptible to case and core hardening comprising 0.05 to 0.24 weight percent carbon; 15 to 28 weight percent cobalt and 1.5 to 9.5 weight percent in nickel, small percentages of one or more additives: chromium, molybdenum, and vanadium; and the balance iron.

Claims

1. A class of steel alloys comprising, in combination:

a case hardened mixture of about 0.05 to 0.24 weight percent carbon in combination with about 15 to 28 weight percent cobalt, about 1.5 to 9.5 percent weight percent nickel, and one or more additives selected from the group consisting of;

about 3.5 to 9.0 weight percent chromium, up to about 2.5 weight percent molybdenum, and up to 0.2 weight percent vanadium; and

the balance iron, said alloy in the form of an article of manufacture.

2. A gear comprising an alloy of a case hardened mixture of about 0.05 to 0.24 weight percent carbon in combination with about 15 to 28 weight percent cobalt, about 1.5 to 9.5 percent weight percent nickel, and one or more additives selected from the group consisting of:

about 3.5 to 9.0 weight percent chromium, up to about 2.5 weight percent molybdenum, and up to 0.2 weight percent vanadium; and

the balance iron, said gear having a case and a core, said case hardened relative to the core.

3. An article of manufacture made from a material from a class of steel alloys comprising in combination:

a mixture of about 0.05 to 0.24 weight percent carbon in combination with about 15 to 28 weight percent cobalt, about 1.5 to 9.5 weight percent nickel and one or more additives selected from the group consisting of about 3.5 to 9.0 weight percent chromium, up to about 2.5 weight percent molybdenum and up to about 0.2 weight percent vanadium; and

the balance iron, said mixture being formed into a case hardened article of manufacture by carburization.

4. The article of claim 3 wherein the surface of the article is case hardened in the range greater than about 60 Rockwell C.

5. The article of claim 3 wherein the core of the article is hardened in the range greater than about 50 Rockwell C.