Cold Rolled Steel Sheet And Steel Member

Abstract: This cold-rolled steel sheet has a predetermined chemical composition, and when the sheet thickness in units of millimeters is defined as t and a position range of t/8 to 3t/8 from the surface in the sheet thickness direction is defined as a t/4 position, a microstructure at the t/4 position contains, in terms of volume ratio, at least 95% of martensite. In this microstructure, the volume ratio of tempered martensite is 95% or less, the prior austenite grain size is 7.0 µm or less, and the grain boundary segregation degree of Mn is 2.0 or less.

Patent Information

Application #

Filing Date

11 September 2025

Publication Number

48/2025

Publication Type

INA

Invention Field

METALLURGY

Status

Email

Parent Application

Applicants

NIPPON STEEL CORPORATION

6-1, Marunouchi 2-chome, Chiyoda-ku, Tokyo 1008071

Inventors

1. SUZUKI Yuya

c/o NIPPON STEEL CORPORATION, 6-1, Marunouchi 2-chome, Chiyoda-ku, Tokyo 1008071

Specification

Documents

Application Documents

#	Name	Date
1	202517086354-TRANSLATIOIN OF PRIOIRTY DOCUMENTS ETC. [11-09-2025(online)].pdf	2025-09-11
2	202517086354-STATEMENT OF UNDERTAKING (FORM 3) [11-09-2025(online)].pdf	2025-09-11
3	202517086354-REQUEST FOR EXAMINATION (FORM-18) [11-09-2025(online)].pdf	2025-09-11
4	202517086354-PROOF OF RIGHT [11-09-2025(online)].pdf	2025-09-11
5	202517086354-PRIORITY DOCUMENTS [11-09-2025(online)].pdf	2025-09-11
6	202517086354-POWER OF AUTHORITY [11-09-2025(online)].pdf	2025-09-11
7	202517086354-FORM 18 [11-09-2025(online)].pdf	2025-09-11
8	202517086354-FORM 1 [11-09-2025(online)].pdf	2025-09-11
9	202517086354-DRAWINGS [11-09-2025(online)].pdf	2025-09-11
10	202517086354-DECLARATION OF INVENTORSHIP (FORM 5) [11-09-2025(online)].pdf	2025-09-11
11	202517086354-COMPLETE SPECIFICATION [11-09-2025(online)].pdf	2025-09-11