Title:
STEEL SHEET, MEMBER, METHOD FOR PRODUCING SAID STEEL SHEET, AND METHOD FOR PRODUCING SAID MEMBER
Document Type and Number:
WIPO Patent Application WO/2022/209520
Kind Code:
A1
Abstract:
Provided is a steel sheet that has a tensile strength of at least 1,310 MPa and is capable of achieving excellent press formability using steel that mainly comprises a martensite structure that has excellent delayed fracture resistance. The steel sheet has: an ingredient composition that includes, in % by mass, 0.12%–0.40% C, no more than 1.5% Si, more than 1.7% and no more than 3.5% Mn, no more than 0.05% P, no more than 0.010% S, no more than 1.00% sol. Al, no more than 0.010% N, 0.002%–0.080% Ti, and 0.0002%–0.0050% B, with the remainder being Fe and unavoidable impurities; a metal structure that has an area ratio, relative to the entire martensite structure, of at least 85%, and a ratio between the length LS of a sub-block boundary in the martensite relative to the length LB of the block boundary, LS/LB, which fulfills a prescribed formula (1); and a tensile strength of at least 1,310 MPa.
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Inventors:
YOSHIOKA SHIMPEI (JP)
KANEKO SHINJIRO (JP)
HONDA YUMA (JP)
KANEKO SHINJIRO (JP)
HONDA YUMA (JP)
Application Number:
PCT/JP2022/008469
Publication Date:
October 06, 2022
Filing Date:
February 28, 2022
Export Citation:
Assignee:
JFE STEEL CORP (JP)
International Classes:
C21D9/46; C22C38/00; C22C38/14; C22C38/60
Domestic Patent References:
| WO2016129214A1 | 2016-08-18 | |||
| WO2017115748A1 | 2017-07-06 | |||
| WO2016152163A1 | 2016-09-29 | |||
| WO2021149676A1 | 2021-07-29 |
Foreign References:
| JP2011202195A | 2011-10-13 | |||
| JP2014196557A | 2014-10-16 | |||
| JP2010248565A | 2010-11-04 | |||
| JP2010215958A | 2010-09-30 | |||
| JP6017341B2 | 2016-10-26 | |||
| JP2019002078A | 2019-01-10 |
Attorney, Agent or Firm:
SUGIMURA Kenji (JP)
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