Cold-rolled high strength steel plate with composite steel structure of high r-value and method for producing same
US4426235A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 26, 1982 |
| Grant date | Jan 17, 1984 |
| Priority date | — |
| Expiry date | Jan 26, 2002 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/008
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A cold-rolled high strength steel plate with excellent formability and baking hardenability, has the composition (% by weight) 0.2-0.15% of C, 0.02-0.7% of Mn, 0.01-0.1% of Al and 0.002-0.01% of N, optionally at least one element selected from the group consisting of 0.01-0.8% of Si, 0.01-0.1% of P, 0.0002-0.005% of B and 0.01-0.5% of V, and a microstructure comprising ferrite containing 2-30% of bainite and less than 8% of martensite. The steel plate is produced by hot and cold rolling steel of the defined composition followed by rapidly heating to a temperature between the Ac.sub.1 and Ac.sub.3 transformation points, holding at this temperature for less than 5 minutes, and quenching to a temperature below 500.degree. C. at a cooling rate between 50.degree. and 500.degree. C./sec.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.