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:
Mar. 01, 2022
Filed:
Oct. 31, 2018
Nippon Steel Corporation, Tokyo, JP;
Yoko Sueyasu, Tokyo, JP;
Hiroaki Tahira, Tokyo, JP;
Ken Yoshino, Tokyo, JP;
Kison Nishihara, Tokyo, JP;
NIPPON STEEL CORPORATION, Tokyo, JP;
Abstract
A hot forged steel material in the present embodiment includes a chemical composition that consists of, in mass %, C: 0.14 to 0.20%, Si: 0.20 to 1.00%, Mn: 1.00 to 1.90%, P: 0.030% or less, S: 0.030% or less, V: 0.16 to 0.30%, Al: 0.015 to 0.050%, N: 0.0050 to 0.0250%, Cr: 0.10 to 0.30%, Cu: 0 to 0.10%, and Nb: 0 to 0.10%, with the balance being Fe and impurities, and that satisfies Formula (1) and Formula (2), wherein a grain size number of ferrite in the steel is 9.0 or more, and an absorbed energy at −30° C. is 100 J or more in the Charpy impact test using a V notch specimen.0.36≤C+(Si+Mn)/6+(Cr+V)/5+Cu/15<0.68  (1)51/12×C−V≤0.52  (2)