Invention Grant
- Patent Title: High-strength steel sheet
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Application No.: US17054467Application Date: 2019-07-26
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Publication No.: US11486028B2Publication Date: 2022-11-01
- Inventor: Mai Nagano , Koutarou Hayashi , Akihiro Uenishi
- Applicant: NIPPON STEEL CORPORATION
- Applicant Address: JP Tokyo
- Assignee: NIPPON STEEL CORPORATION
- Current Assignee: NIPPON STEEL CORPORATION
- Current Assignee Address: JP Tokyo
- Agency: Birch, Stewart, Kolasch & Birch, LLP
- Priority: JPJP2018-141244 20180727
- International Application: PCT/JP2019/029432 WO 20190726
- International Announcement: WO2020/022481 WO 20200130
- Main IPC: C22C38/58
- IPC: C22C38/58 ; C22C38/02 ; C21D8/02 ; C21D9/46 ; C22C38/06

Abstract:
What is provided is a high-strength steel sheet having a large bake hardening amount and a uniform bake hardenability is provided according to the present invention, the high-strength steel sheet comprising, by mass %: C: 0.13% to 0.40%; Si: 0.500% to 3.000%; Mn: 2.50% to 5.00%; P: 0.100% or less; S: 0.010% or less; Al: 0.001% to 2.000%; N: 0.010% or less; and a remainder consisting of Fe and impurities, wherein martensite is 95% or more in an area ratio, and residual structure is 5% or less in an area ratio, a ratio C1/C2 of an upper limit C1 (mass %) of Si concentrations to a lower limit C2 (mass %) of the Si concentrations in a cross section in a thickness direction is 1.25 or less, precipitates having a major axis of 0.05 μm or more and 1.00 μm or less and an aspect ratio of 1:3 or more are included in a number density of 30/μm2 or more, and a tensile strength is 1300 MPa or more.
Public/Granted literature
- US20210164082A1 HIGH-STRENGTH STEEL SHEET Public/Granted day:2021-06-03
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