High-strength steel sheet and process for producing the same
US8177924B2 · kind B2 · utility
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Key dates
| Filing date | Jun 1, 2007 |
| Grant date | May 15, 2012 |
| Priority date | — |
| Expiry date | May 24, 2028 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/005
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A high-strength steel sheet comprises a metallic structure consisting of a ferrite phase and a hard second phase dispersed in the ferrite phase, the hard second phase in the metallic structure having an area ratio of 30 to 70%, and the ferrite of which grain sizes are not more than 1.2 μm having an area ratio of 15 to 90% in the ferrite phase. The term ds is an average grain size of the ferrite of which grain sizes are not more than 1.2 μm, the term dL is an average grain size of ferrite of which grain sizes are more than 1.2 μm, and the ds and the dL satisfy the following equation (1):dL/ds≧3 (1).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.