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:
Jan. 21, 2025
Filed:
Jun. 25, 2019
Jfe Steel Corporation, Tokyo, JP;
Masafumi Tada, Tokyo, JP;
JFE STEEL CORPORATION, Tokyo, JP;
Abstract
Disclosed is a non-heat-treated steel that has low deformation resistance during cold forging in bolt head forming and excellent product yield, and that can be manufactured without the need to perform heat treatment for controlling strength variation. The disclosed steel has a chemical composition containing C: 0.18-0.24%, Si: 0.10-0.22%, Mn: 0.60-1.00%, Al: 0.010-0.050%, Cr: 0.65-0.95%, Ti: 0.010-0.050%, B: 0.0015-0.0050%, N: 0.0050-0.0100%, P: 0.025% or less inclusive of 0, S: 0.025% or less inclusive of 0, Cu: 0.20% or less inclusive of 0, and Ni: 0.30% or less inclusive of 0, in a range satisfying: 0.45≤C+Si/24+Mn/6+Ni/40+Cr/5≤0.60 and N≤0.519Al+0.292Ti, with the balance being Fe and inevitable impurities; and a microstructure in which bainite is present in an area ratio of 95% or more, where the microstructure contains prior austenite grains with a grain size number of 6 or more, and strength variation is 100 MPa or less.