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:
Aug. 02, 2016
Filed:
May. 02, 2013
Nhk Spring Co., Ltd., Yokohama-shi, Kanagawa, JP;
Hideki Okada, Yokohama, JP;
Akira Tange, Yokohama, JP;
Koichi Tango, Yokohama, JP;
Isao Sumiyoshi, Yokohama, JP;
NHK SPRING CO., LTD., Yokohama-Shi, Kanagawa, JP;
Abstract
A steel for high-strength spring has an Actransformation temperature as an indicator of the decarburization performance, which is calculated by Equation (1) below, is from 859 to 885° C., a maximum hardened diameter DI as an indicator of the hardening performance, which is calculated by Equation (2) below, is from 70 to 238 mm, and a temper hardness HRC as an indicator of the spring performance, which is calculated by Equation (3) below, is from 50 to 55.Ac=910−203×√{square root over (C)}−15.2Ni+44.7Si+104V+31.5Mo+13.1W  (1)DI=D  (2)HRC=38.99+17.48C+2.55Si−2.28Ni+2.37Cr+8.04Ti  (3)wherein, D=8.65×√{square root over (C)}, f=1+0.64×% Si, f=1+4.10×% Mn, f=1+2.83×% P, f=1−0.62×% S, f=1+0.27×% Cu, f=1+0.52×% Ni, and f=1+2.33×% Cr.