High-strength steel sheet and method for manufacturing the same
US11345973B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 29, 2018 |
| Grant date | May 31, 2022 |
| Priority date | — |
| Expiry date | Jul 16, 2038 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/008
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Provided are a high-strength steel sheet having a yield strength of 550 MPa or more and excellent fatigue-strength of a weld and a method for manufacturing the steel sheet.A high-strength steel sheet has a specified chemical composition, a steel microstructure observed in a cross section in a thickness direction parallel to a rolling direction including 40% to 75% of a martensite phase in terms of volume fraction, in which a total volume fraction of martensite grains whose average grain diameter ratios with respect to adjacent ferrite grains are ¼ or more and 1 or less is 60% or more with respect to an entire martensite phase, and a yield strength (YP) of 550 MPa or more.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.