Cold-rolled steel sheet and manufacturing method therefor
US10870902B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 23, 2016 |
| Grant date | Dec 22, 2020 |
| Priority date | — |
| Expiry date | Nov 8, 2037 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/008
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A cold-rolled steel sheet has: a predetermined chemical composition; and a microstructure in which tempered martensite and bainite are contained in a total area ratio of 95-100% with respect to a whole volume of the microstructure; a number of predetermined inclusion groups is at most 0.8/mm2, the inclusion groups being formed by one or more inclusion particles, the one or more inclusion particles having a major axis length of 0.3 μm or more and extending and/or distributed in a dot-sequence manner along a rolling direction; a number of carbides mainly composed of Fe having a predetermined size is at most 3,500/mm2; a number of carbides that are distributed in the tempered martensite and/or in the bainite and that have a diameter of 10 nm to 50 nm is at least 0.7×107/mm2; and prior γ grains have a mean grain size of 18 μm or less.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.