The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Apr. 16, 1991

Filed:

Mar. 08, 1989
Applicant:
Inventors:

Shohachi Nishiuchi, Saitama, JP;

Shigeo Ohta, Saitama, JP;

Hitoshi Imai, Saitama, JP;

Haruo Meguro, Saitama, JP;

Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
B21J / ; B21C / ; B21K / ;
U.S. Cl.
CPC ...
72 44 ; 72358 ; 72352 ;
Abstract

A billet is successively cold worked into a product such as a countershaft, an outer race for a constant-velocity joint, or the like by forming a chemically converted lubricating coating on a surface of the billet, forging the billet into an intermediate product at a temperature below a transformation temperature of the billet, covering a surface of said intermediate product with lubricating oil in a die cavity in a die assembly, and forging the intermdiate product at a temperature below the transformation temperature and before the intermediate product gains a predetermined hardness due to age hardening resulting from the first forging step.


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