High-strength cold rolled steel sheet and process for producing the same
US7559997B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 23, 2003 |
| Grant date | Jul 14, 2009 |
| Priority date | — |
| Expiry date | Jul 19, 2024 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/008
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The invention provides a high strength cold rolled steel sheet comprising ferrite phases and second phases, in which the mean grain size of the ferrite phases is 20 μm or less, the volume fraction of the second phase is 0.1% or more to less than 10%, the absolute value |Δr| of in-plane anisotropy of r value is less than 0.15, and the thickness is 0.4 mm or more. The high strength cold rolled steel sheet of the present invention has a tensile strength of 370 to 590 MPa, and has excellent stretchability, dent resistance, surface precision, secondary working embrittlement, anti-aging, and surface appearance, therefore it is suitable for outer panels of automobile.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.