Title:
STEEL SHEET AND STEEL SHEET MANUFACTURING METHOD
Document Type and Number:
WIPO Patent Application WO/2022/070608
Kind Code:
A1
Abstract:
This steel sheet has a predetermined chemical composition. At a 1/4 depth position of the sheet thickness from the surface, the area percentage of GAM0.5-1.7 is 50-100%, the area percentage of GAM>1.7 is 0-20%, the area percentage of GAM≤0.5 is 0% or more but less than 50%, the area percentage of retained austenite is 0% or more but less than 4%, and the total area percentage, the average grain size, and the average dislocation density of the retained austenite, fresh martensite, cementite, and perlite are 0-10%, 15.0 μm or less, and 1.0×1014/m2-4.0×1015/m2, respectively. At a sheet thickness center portion, the total of pole densities of {211}<011> and {332}<113> is 12.0 or less, and the tensile strength is 980 MPa or more.
Inventors:
YOSHIDA MITSURU (JP)
YAMAZAKI TSUYOSHI (JP)
YAMAZAKI TSUYOSHI (JP)
Application Number:
PCT/JP2021/029121
Publication Date:
April 07, 2022
Filing Date:
August 05, 2021
Export Citation:
Assignee:
NIPPON STEEL CORP (JP)
International Classes:
C21D9/46; C22C38/00; C22C38/58
Domestic Patent References:
| WO2014188966A1 | 2014-11-27 | |||
| WO2014132968A1 | 2014-09-04 | |||
| WO2019009410A1 | 2019-01-10 | |||
| WO2020022778A1 | 2020-01-30 | |||
| WO2014132968A1 | 2014-09-04 |
Foreign References:
| JP2020164941A | 2020-10-08 | |||
| JP2008255484A | 2008-10-23 | |||
| JP2014205890A | 2014-10-30 | |||
| JP2009084648A | 2009-04-23 |
Other References:
TSUCHIYAMA, T: "Heat Treatment", vol. 42, 2002, article "Physical Meaning of Tempering Parameter and Its Application for Continuous Heating or Cooling Heat Treatment Process", pages: 163 - 168
See also references of EP 4223892A4
See also references of EP 4223892A4
Attorney, Agent or Firm:
TANAI Sumio et al. (JP)
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