Cold-rolled steel sheet having excellent bendability and hole expandability and method for manufacturing same
US12428691B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 2017 |
| Grant date | Sep 30, 2025 |
| Priority date | — |
| Expiry date | May 28, 2040 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/008
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Provided are a cold-rolled steel sheet and a method for manufacturing same, the steel sheet containing, by weight %, 0.03 to 0.07% of C, 0.3% or less of Si, 2.0 to 3.0% of Mn, 0.01 to 0.10% of Sol·Al, 0.3 to 1.2% of Cr, 0.03 to 0.08% of Ti, 0.01 to 0.05 of Nb, 0.0010 to 0.0050% of B, 0.001-0.10% of P, 0.010% or less of S, 0.010% or less of N, the balance being Fe and other impurities, and having a microstructure comprising 75% or more to less than 87% by area of a transformed structure and 13 to 25% by area of ferrite, wherein the transformed structure includes martensite and bainite, the martensite has an average particle diameter of 2 μm or less, the bainite has an average particle diameter of 3 μm or less, the bainite fraction of 3 μm or more is 5% or less.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.