Title:
HIGH-STRENGTH STEEL SHEET AND METHOD FOR PRODUCING SAME
Document Type and Number:
WIPO Patent Application WO/2023/135980
Kind Code:
A1
Abstract:
The present invention provides a high-strength steel sheet which has a tensile strength of 1,320 MPa or more, while exhibiting excellent bore expanding properties and delayed fracture resistance. This high-strength steel sheet has a specific component composition; the amount of diffusible hydrogen in the steel is 0.50 ppm by mass or less; tempered martensite and bainite are 70.0% or more; fresh martensite is 15.0% or less; iron-based carbides present in the tempered martensite and bainite have an average circle-equivalent radius of 0.10 µm or less and an average aspect ratio of 4.5 or less; and the proportion p of tempered martensite and bainite containing iron-based carbides, which have major axes facing the same direction within the range of 0° to 10°, at a number density of 7 to 35 per µm2 is 25% to 70%.
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Inventors:
MORIMOTO RYOHEI (JP)
YANG LINGLING (JP)
TOJI YUKI (JP)
YANG LINGLING (JP)
TOJI YUKI (JP)
Application Number:
PCT/JP2022/044851
Publication Date:
July 20, 2023
Filing Date:
December 06, 2022
Export Citation:
Assignee:
JFE STEEL CORP (JP)
International Classes:
C22C38/00; C21D9/46; C22C38/60; C22C18/00
Domestic Patent References:
| WO2021019947A1 | 2021-02-04 | |||
| WO2018055695A1 | 2018-03-29 | |||
| WO2020179387A1 | 2020-09-10 |
Foreign References:
| JP2021123801A | 2021-08-30 | |||
| JP2016050343A | 2016-04-11 |
Attorney, Agent or Firm:
ITOH Hideaki et al. (JP)
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