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:
Jun. 25, 2019
Filed:
Jan. 23, 2012
Yoshihiro Daitoh, Chiba, JP;
Yoshihiro Daitoh, Chiba, JP;
NIPPON STEEL & SUMITOMO METAL CORPORATION, Tokyo, JP;
Abstract
A steel for carburizing or carbonitriding use consisting of, by mass %, C: 0.1 to 0.3%, Si: 0.01 to 0.15%, Mn: 0.6 to 1.5%, S: 0.012 to 0.05%, Cr: 0.5 to 2.0%, Al: 0.030 to 0.050%, Ti: 0.0006 to 0.0025%, N: 0.010 to 0.025%, and O: 0.0006 to 0.0012%, and, optionally, at least one selected from Mo≤0.5%, Ni≤1.5% and Cu≤0.4%, and the balance of Fe and impurities. P and Nb are P≤0.025% and Nb≤0.003% respectively. Formulas of [−5.0≤log (Ti×N)≤−4.4] and [−12.5≤log (Al×O)≤−11.7] are satisfied. Austenite grain coarsening is prevented even when the steel is heated in the process of carburizing or carbonitriding, and even under various hot forging temperatures. The steel has excellent bending fatigue strength after carburizing or carbonitriding.