Hot-rolled steel sheet and method for manufacturing same
US11492679B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 21, 2019 |
| Grant date | Nov 8, 2022 |
| Priority date | — |
| Expiry date | Oct 21, 2039 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/008
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
This hot-rolled steel sheet has a predetermined chemical composition, in which in a case where the thickness is denoted by t, a metallographic structure at a t/4 position from the surface includes, by area fraction, 77.0% to 97.0% of bainite or tempered martensite, 0% to 5.0% of ferrite, 0% to 5.0% of pearlite, 3.0% or more of residual austenite, and 0% to 10.0% of martensite, in the metallographic structure, the average grain size excluding the residual austenite is 7.0 μm or less, the average number density of iron-based carbides having a diameter of 20 nm or more is 1.0×106 carbides/mm2 or more, a tensile strength is 980 MPa or more, and an average Ni concentration on the surface is 7.0% or more.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.