Method for producing a high strength coated steel sheet having improved strength, formability and obtained sheet
US11718888B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 23, 2020 |
| Grant date | Aug 8, 2023 |
| Priority date | — |
| Expiry date | Jul 11, 2041 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/008
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method is for producing a high strength coated steel sheet having an improved ductility and an improved formability, and a chemical composition containing: 0.13%≤C≤0.22%, 1.9%≤Si≤2.3%, 2.4%≤Mn≤3%, Al≤0.5%, Ti≤0.05%, Nb≤0.05%, the remainder being Fe and unavoidable impurities. The sheet is annealed at temperature TA higher than Ac3 but less than 1000° C. for a time of more than 30 s, quenched by cooling to a quenching temperature QT between 200° C. and 280° C. in order to obtain a structure consisting of austenite and at least 50% of martensite, the austenite content being such that the final structure can contain between 3% and 15% of residual austenite and between 85% and 97% of the sum of martensite and bainite, without ferrite, heated up to a partitioning temperature PT between 430° C. and 490° C. and maintained at this temperature for a time Pt between 10 s and 100 s, hot dip coated and cooled to the room temperature.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.