High-strength steel sheet and method of manufacturing the same
US11085107B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 13, 2016 |
| Grant date | Aug 10, 2021 |
| Priority date | — |
| Expiry date | Feb 11, 2038 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/005
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A steel sheet has a composition containing, by mass %, C: 0.04% to 0.20%, Si: 0.6% to 1.5%, Mn: 1.0% to 3.0%, P: 0.10% or less, S: 0.030% or less, Al: 0.10% or less, N: 0.010% or less, one, two, or all of Ti, Nb, and V in an amount of 0.01% to 1.0% each, and the balance being Fe and inevitable impurities, a microstructure including, in terms of area ratio, 50% or more of ferrite, in which an average grain diameter at a position located 50 μm from a surface of the steel sheet in a thickness direction is 3000×(tensile strength TS (MPa))−0.85 μm or less, C precipitates having a grain diameter of less than 20 nm formed in steel is 0.010 mass % or more, and a amount of precipitated Fe is 0.03 mass % to 1.0 mass %, and a roughness Ra of 3.0 μm or less.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.