Steel Sheet And Manufacturing Method Of Steel Sheет

Abstract: A steel sheet according to an aspect of the present invention has a predetermined chemical composition. A ratio Hs/Hc between the Vickers hardness Hs of a surface layer soft portion and the Vickers hardness Hc at the 1/4 depth position is 0.65 or smaller. In the ferrite in the surface layer soft portion, a ratio ML/ Mc between the Taylor factor M value ML of the L cross-section and the Taylor factor M value Mc of the C cross-section is 0.95 or greater. An island-shaped hard phase in the surface layer soft portion has an aspect ratio of 3.0 or smaller and a long diameter of 5.0 µm or smaller.

Patent Information

Application #

Filing Date

03 June 2025

Publication Number

28/2025

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. ISHIKAWA Kyohei

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

2. YOKOYAMA Takafumi

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

3. TAKEDA Kengo

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

Specification

Documents

Application Documents

#	Name	Date
1	202517053673-TRANSLATIOIN OF PRIOIRTY DOCUMENTS ETC. [03-06-2025(online)].pdf	2025-06-03
2	202517053673-STATEMENT OF UNDERTAKING (FORM 3) [03-06-2025(online)].pdf	2025-06-03
3	202517053673-REQUEST FOR EXAMINATION (FORM-18) [03-06-2025(online)].pdf	2025-06-03
4	202517053673-PROOF OF RIGHT [03-06-2025(online)].pdf	2025-06-03
5	202517053673-PRIORITY DOCUMENTS [03-06-2025(online)].pdf	2025-06-03
6	202517053673-POWER OF AUTHORITY [03-06-2025(online)].pdf	2025-06-03
7	202517053673-FORM 18 [03-06-2025(online)].pdf	2025-06-03
8	202517053673-FORM 1 [03-06-2025(online)].pdf	2025-06-03
9	202517053673-DECLARATION OF INVENTORSHIP (FORM 5) [03-06-2025(online)].pdf	2025-06-03
10	202517053673-COMPLETE SPECIFICATION [03-06-2025(online)].pdf	2025-06-03
11	202517053673-FORM 3 [24-10-2025(online)].pdf	2025-10-24