Steel sheet and plated steel sheet
US11649531B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 4, 2017 |
| Grant date | May 16, 2023 |
| Priority date | — |
| Expiry date | Sep 1, 2038 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC22C2204/00
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A steel sheet has a specific chemical composition and has a structure represented by, by area ratio, ferrite: 5 to 60%, and bainite: 40 to 95%. When a region that is surrounded by a grain boundary having a misorientation of 15° or more and has a circle-equivalent diameter of 0.3 μm or more is defined as a crystal grain, the proportion of crystal grains each having an intragranular misorientation of 5 to 14° to all crystal grains is 20 to 100% by area ratio. A precipitate density of Ti(C,N) and Nb(C,N) each having a circle-equivalent diameter of 10 nm or less is 1010 precipitates/mm3 or more. A ratio (Hvs/Hvc) of a hardness at 20 μm in depth from a surface (Hvs) to a hardness of the center of a sheet thickness (Hvc) is 0.85 or more.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.