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. 20, 1991
Filed:
Nov. 30, 1989
Yoshihisa Miwa, Aki, JP;
Mazda Motor Corporation, Hiroshima, JP;
Abstract
A method for manufacturing a steel member which comprises the steps of preparing a steel material of a composition containing C in a quantity of 0.15 to 0.35 wt %, Si in a quantity of not greater than 0.50 wt %, Mo in a quantity of 0.05 to 0.50 wt %, Mn in a quantity of 0.50 to 1.30 wt %, Cr in a quantity of 0.50 to 1.30 wt %, V in a quantity of 0.05 to 0.20 wt %, N in a quantity not greater than 0.02 wt %, Al in a quantity of not greater than 0.10 wt % and Fe being the balance relative to the total weight of the steel material, wherein the product of the sum of the Mn content and the Cr content times the Mo content is chosen to be within the range of 0.1 to 0.6, hot-forging the steel material at a predetermined heating temperature to provide the steel member, and continuously cooling the steel member at a predetermined cooling speed of 0.4.degree. to 4.0.degree. C./sec to impart a substantially bainite structure or a combined bainite and ferrite structure to the steel member.