Title:
曲げ加工性に優れた黒色表面被覆高強度溶融Ｚｎ−Ａｌ−Ｍｇ系めっき鋼板及びその製造方法
Document Type and Number:
Japanese Patent JP6816550
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide a molten Zn-Al-Mg-based plated steel sheet that has higher tensile strength than the conventional molten Zn-Al-Mg-based plated steel sheet and realizes an improvement in both strength and bending processability at the same time while suppressing an excessive increase in manufacturing cost and to provide a method for manufacturing the plated steel sheet.SOLUTION: There is provided a black surface-coated high-strength molten Zn-Al-Mg-based plated steel sheet excellent in bending processability with a tensile strength of 780 to 1,100 MPa, which is a plated steel sheet having a molten Zn-Al-Mg-based coating layer on the surface of a steel sheet stock having a predetermined chemical composition; comprises as the main phase a single phase composed of either of a bainitic ferrite phase and a ferrite phase each having a dislocation density of 1.8×10/mto 5.7×10/mor a phase including the bainitic ferrite phase and the ferrite phase, has an area ratio of a hard second phase and cementite of 3% or less, has a carbide including Ti with an average particle diameter of 20 nm or less dispersed and precipitated and has a diffusible hydrogen concentration of 0.30 ppm or less; and has a black oxide of Zn distributed in a molten Zn-Al-Mg-based coating layer having a specific composition and has a lightness Lof the coating layer surface of 60 or less. There is also provided a method for manufacturing the black surface-coated high-strength molten Zn-Al-Mg-based plated steel sheet.SELECTED DRAWING: None
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Inventors:
Susumu Fujiwara
Uesugi Shinya
Tomoji Shigetomi
Uesugi Shinya
Tomoji Shigetomi
Application Number:
JP2017027637A
Publication Date:
January 20, 2021
Filing Date:
February 17, 2017
Export Citation:
Assignee:
Nippon Steel Corporation
International Classes:
C22C38/00; C21D3/06; C21D9/46; C22C18/00; C22C18/04; C22C38/14; C23C2/06; C23C2/28; C23C8/12
Domestic Patent References:
| JP2012012658A | ||||
| JP2013241665A | ||||
| JP2013241666A | ||||
| JP2013072121A | ||||
| JP2016160499A | ||||
| JP2014189812A | ||||
| JP9087739A | ||||
| JP2017145441A |
Foreign References:
| WO2015093596A1 | ||||
| WO2016157896A1 |
Attorney, Agent or Firm:
Michiharu Soga
Kajinami order
Kazuhiro Oyaku
Satoshi Iino
Kajinami order
Kazuhiro Oyaku
Satoshi Iino