Surface Treated Steel Sheet

Abstract: [Problem] To further improve corrosion resistance after forming. [Solution] The surface-treated steel sheet according to the present invention has: a plating layer that is located on at least one surface of the steel sheet and contains zinc and nickel; and a coating film that is located on the plating layer and contains at least an epoxy resin and an isocyanate resin. The ratio of the total length of cracks occurring in the coating film to the total length of cracks occurring in the plating layer is 80% or less in a region 60 µm long in a direction orthogonal to the thickness direction when a viewing a cross-section cut in the thickness direction after applying 10% tensile elongation.

Patent Information

Application #

Filing Date

15 October 2025

Publication Number

52/2025

Publication Type

INA

Invention Field

CHEMICAL

Status

Email

Parent Application

Applicants

NIPPON STEEL CORPORATION

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

Inventors

1. FUJII, Takashi

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

2. KAWAMURA, Yasuaki

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

3. TOSHIN, Kunihiko

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

4. NAKAGAWA, Akira

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

Specification

Documents

Application Documents

#	Name	Date
1	202517099611-TRANSLATIOIN OF PRIOIRTY DOCUMENTS ETC. [15-10-2025(online)].pdf	2025-10-15
2	202517099611-STATEMENT OF UNDERTAKING (FORM 3) [15-10-2025(online)].pdf	2025-10-15
3	202517099611-REQUEST FOR EXAMINATION (FORM-18) [15-10-2025(online)].pdf	2025-10-15
4	202517099611-PROOF OF RIGHT [15-10-2025(online)].pdf	2025-10-15
5	202517099611-PRIORITY DOCUMENTS [15-10-2025(online)].pdf	2025-10-15
6	202517099611-POWER OF AUTHORITY [15-10-2025(online)].pdf	2025-10-15
7	202517099611-FORM 18 [15-10-2025(online)].pdf	2025-10-15
8	202517099611-FORM 1 [15-10-2025(online)].pdf	2025-10-15
9	202517099611-DRAWINGS [15-10-2025(online)].pdf	2025-10-15
10	202517099611-DECLARATION OF INVENTORSHIP (FORM 5) [15-10-2025(online)].pdf	2025-10-15
11	202517099611-COMPLETE SPECIFICATION [15-10-2025(online)].pdf	2025-10-15