High-strength thin steel sheet drawable and excellent in shape fixation property and method of producing the same
US7503984B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 4, 2002 |
| Grant date | Mar 17, 2009 |
| Priority date | — |
| Expiry date | Jun 2, 2023 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/008
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The present invention provides a high-strength thin steel sheet drawable and excellent in a shape fixation property and a method of producing the same. For the steel sheet, on a plane at the center of the thickness of a steel sheet, the average ratio of the X-ray strength in the orientation component group of {100}<011> to {223}<110> to random X-ray diffraction strength is 2 or more and the average ratio of the X-ray strength in three orientation components of {554}<225>, {111}<112> and {111}<110> to random X-ray diffraction strength is 4 or less. The arithmetic average of the roughness Ra of at least one of the surfaces is 1 to 3.5 μm; the surfaces of the steel sheet are covered with a composition having a lubricating effect; and the friction coefficient of the steel sheet surfaces at 0 to 200° C. is 0.05 to 0.2. Further, the present invention also relates to a method of producing said steel sheet, characterized by: rolling a steel sheet having the chemical components specified in the present invention at a total reduction ratio of 25% or more in the temperature range of the Ar3 transformation temperature +100° C. or lower.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.