Method for producing an ultra high strength coated or not coated steel sheet and obtained sheet
US11131003B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 15, 2019 |
| Grant date | Sep 28, 2021 |
| Priority date | — |
| Expiry date | Sep 20, 2039 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/26
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method for producing a cold rolled steel sheet having a tensile strength≥1470 MPa and a total elongation TE≥19%, the method comprising the steps of annealing at an annealing temperature AT≥Ac3 a non-treated steel sheet whose chemical composition contains in weight %: 0.34%≤C≤0.40%, 1.50%≤Mn≤2.30%, 1.50≤Si≤2.40%, 0%<Cr≤0.5%, 0%<Mo≤0.3%, 0.01%≤Al≤0.07%, the remainder being Fe and unavoidable impurities, quenching the annealed steel sheet by cooling it to a quenching temperature QT<Ms transformation point and between 150° C. and 250° C., and making a partitioning treatment by reheating the quenched steel sheet to a partitioning temperature PT between 350° C. and 420° C. and maintaining the steel sheet at this temperature during a partitioning time Pt between 15 seconds and 120 seconds.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.