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:
Apr. 24, 2018
Filed:
Feb. 05, 2013
Nippon Steel & Sumitomo Metal Corporation, Tokyo, JP;
Denso Corporation, Aichi, JP;
Naoki Matsui, Tokyo, JP;
Masashi Higashida, Tokyo, JP;
Hitoshi Matsumoto, Tokyo, JP;
Yutaka Neishi, Tokyo, JP;
Taizo Makino, Tokyo, JP;
Kouji Morita, Aichi, JP;
Yoshihiro Tanimura, Aichi, JP;
Naoyuki Sashima, Aichi, JP;
Toshimasa Itou, Aichi, JP;
NIPPON STEEL & SUMITOMO METAL CORPORATION, Tokyo, JP;
DENSO CORPORATION, Aichi, JP;
Abstract
A rolled steel bar for hot forging consisting, by mass percent, of C: 0.25-0.50%, Si: 0.40-1.0%, Mn: 1.0-1.6%, S: 0.005-0.035%, Al: 0.005-0.050%, V: 0.10-0.30%, and N: 0.005-0.030%, and the balance of Fe and impurities, i.e., P: 0.035% or less and O: 0.0030% or less, wherein Fn1=C+Si/10+Mn/5+5Cr/22+1.65V−5S/7 is 0.90 to 1.20. The predicted maximum width of nonmetallic inclusions at the time when a cumulative distribution function obtained by extreme value statistical processing by taking the width of nonmetallic inclusion in an R/2 part of a longitudinal cross section of the steel bar as W (μm) is 99.99% is 100 μm or narrower. The number density of sulfides each having a circle-equivalent diameter of 0.3 to 1.0 μm observed per unit area of the R/2 part of a transverse cross section of the steel bar is 500 pieces/mmor higher.