High strength cold rolled steel sheet with high yield ratio and method for producing the same
US9994941B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 3, 2012 |
| Grant date | Jun 12, 2018 |
| Priority date | — |
| Expiry date | Jan 16, 2035 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/009
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A high strength cold rolled steel sheet has a chemical composition including, by mass %, C: 0.06 to 0.13%, Si: 1.2 to 2.3%, Mn: 0.6 to 1.6%, P: not more than 0.10%, S: not more than 0.010%, Al: 0.01 to 0.10% and N: not more than 0.010%, the balance comprising Fe and inevitable impurities. The steel sheet includes a microstructure containing not less than 90% in terms of volume fraction of ferrite with an average grain diameter of less than 20 μm and 1.0 to 10% in terms of volume fraction of pearlite with an average grain diameter of less than 5 μm. The ferrite has an average Vickers hardness of not less than 130. The steel sheet has a yield ratio of not less than 65% and a tensile strength of not less than 590 MPa.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.