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.
Patent No.:
Date of Patent:
Jul. 06, 1993
Filed:
Mar. 13, 1992
Hiroshi Koyama, Yokohama, JP;
Yasuo Sato, Yokohama, JP;
Katsuyuki Nishioka, Yokohama, JP;
Akira Tange, Yokohama, JP;
Tadayoshi Akutsu, Yokohama, JP;
NHK Spring Co., Ltd., Yokohama, JP;
Abstract
A spring steel containing 0.35 to 0.50% of carbon is refined to the hardness of .phi. 2.50 to 2.70 mm in Brinell indentation diameter (HBD) by rapid cooling for quenching and tempering. This spring steel is subjected to warm shot peening at a temperature of 150.degree. to 300.degree. C. (423 to 573 K.) by using long-lived practical shots with the normal hardness of .phi. 2.65 to 2.80 mm in HBD, whereupon a high-strength spring is obtained having a compressive residual stress in its surface and enjoying the maximum shearing stress of 110 to 135 kgf/mm.sup.2 (1080 to 1325 MPa).