Hot-rolled steel sheet for high-strength galvanized steel sheet or high-strength galvannealed steel sheet and method for manufacturing the same (as amended)
US9758847B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 2, 2012 |
| Grant date | Sep 12, 2017 |
| Priority date | — |
| Expiry date | Nov 2, 2032 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D9/46
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Provided is a hot-rolled steel sheet having a composition containing 0.04 mass percent to 0.20 mass percent C, 0.7 mass percent to 2.3 mass percent Si, 0.8 mass percent to 2.8 mass percent Mn, 0.1 mass percent or less P, 0.01 mass percent or less S, 0.1 mass percent or less Al, and 0.008 mass percent or less N, the remainder being Fe and inevitable impurities. Internal oxides containing one or more selected from the group consisting of Si, Mn, and Fe are present at grain boundaries and in grains in a base metal. The internal oxides present at the grain boundaries in the base metal are located within 5 μm from the surface of the base metal. The difference between the depths at which the internal oxides are formed in the cross direction of the steel sheet is 2 μm or less.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.