Title:
HIGH-STRENGTH STEEL SHEET AND METHOD FOR MANUFACTURING SAME
Document Type and Number:
WIPO Patent Application WO/2022/209838
Kind Code:
A1
Abstract:
The purpose of the present invention is to provide a high-strength steel sheet having a tensile strength of at least 980 MPa, press formability, and fatigue resistance characteristics, and to provide a method for manufacturing the same. The high-strength steel sheet has a component composition in which the MSC defined by a specific formula is 2.7-3.8 mass%, and the microstructure thereof has a specific structure in a surface layer region up to a depth of 100 μm from the steel sheet surface and in an inner region other than the surface layer region. The maximum height of the surface roughness of the steel sheet is 30 μm or less, the tensile strength is 980 MPa or more, the uniform elongation is 6% or more, and the ratio (fatigue limit ratio) of the 107-fold bending fatigue strength to the tensile strength is at least 0.45.
Inventors:
DOAN THI HUYEN (JP)
HASEGAWA HIROSHI (JP)
KIMURA HIDEYUKI (JP)
HASEGAWA HIROSHI (JP)
KIMURA HIDEYUKI (JP)
Application Number:
PCT/JP2022/011492
Publication Date:
October 06, 2022
Filing Date:
March 15, 2022
Export Citation:
Assignee:
JFE STEEL CORP (JP)
International Classes:
C21D8/02; C21D9/46; C22C38/00; C22C38/06; C22C38/60
Domestic Patent References:
| WO2018150955A1 | 2018-08-23 | |||
| WO2016010004A1 | 2016-01-21 | |||
| WO2014188966A1 | 2014-11-27 |
Foreign References:
| JP2016050335A | 2016-04-11 | |||
| JP2012012701A | 2012-01-19 |
Attorney, Agent or Firm:
KUMASAKA Akira et al. (JP)
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