High-strength steel sheet and method for manufacturing the same
US10760142B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 28, 2015 |
| Grant date | Sep 1, 2020 |
| Priority date | — |
| Expiry date | Oct 28, 2036 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC22C38/60
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Provided are a high-strength steel sheet and a method for manufacturing the steel sheet. The high-strength steel sheet has a specified chemical composition with the balance being Fe and inevitable impurities, a microstructure including, in terms of area ratio, 30% or more of a ferrite phase, 40% to 65% of a bainite phase and/or a martensite phase, and 5% or less of cementite, in which, in a surface layer that is a region within 50 μm from the surface in the thickness direction, the area ratio of a ferrite phase is 40% to 55% and the total area ratio of a bainite phase having a grain diameter of more than 5 μm and/or a martensite phase having a grain diameter of more than 5 μm is 20% or less, and a tensile strength is 980 MPa or more.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.