公开(公告)号：US12227851B2

公开(公告)日：2025-02-18

申请号：US16615955

申请日：2017-09-01

Applicant: NIPPON STEEL NISSHIN CO., LTD.

Inventor： Susumu Fujiwara ,  Shinya Uesugi ,  Tomoharu Shigetomi

IPC: C23C2/06 ,  C21D3/06 ,  C21D8/02 ,  C22C18/04 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C22C38/32 ,  C23C2/02 ,  C23C2/26 ,  C23C2/28

Abstract: A high-strength surface-coated steel sheet includes a base steel sheet having a composition by mass of C: 0.01 to 0.20%, Si: 0.01 to 0.50%, Mn: 0.10 to 2.50%, P: 0.005 to 0.050%, B: 0.0005 to 0.010%, Ti: 0.01 to 0.20%, Nb: 0 to 0.10%, Mo: 0 to 0.50%, Cr: 0 to 0.50%, Al: 0.01 to 0.10%, and the balance of Fe and inevitable impurities; and a Zn—Al—Mg-based coating layer disposed on a surface of the base steel sheet, The steel sheet has a diffusible hydrogen concentration in the base steel sheet of 0.30 ppm or less and having a time until occurrence of red rust of 7000 hours or more as measured by a salt spray test. The high-strength hot-dip Zn—Al—Mg-based-plated steel sheet has a significantly lowered in-steel concentration of hydrogen which has entered the steel in a plating line and exhibits excellent corrosion resistance.