Method of manufacturing steel sheet having excellent deep-drawability
US4973367A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 22, 1989 |
| Grant date | Nov 27, 1990 |
| Priority date | — |
| Expiry date | Dec 22, 2009 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D8/0478
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method of manufacturing a steel sheet having excellent deep-drawability. A steel blank is rolled into a steel sheet having a predetermined thickness. The steel contains C: not more than 0.008 wt %, Si: not more than 0.5 wt %, Mn: not more than 1.0 wt %, P: not more than 0.15 wt %, S: not more than 0.02 wt %, Al: 0.010 to 0.10 wt %, N: not more than 0.008 wt %, and at least one element selected from the group consisting of Ti and Nb which is contained in an amount satisfying the relationship of 1.2 (C/12+N/14).ltoreq.(Ti/48+Nb/93). In at least one pass, rolling is conducted within a temperatures range lower than the Ar3 transformation point but not lower than 500.degree. C., in such a manner that the roll radius R (mm) and the blank thickness t (mm) before rolling by rolls satisfy the relationships of R.ltoreq.200 and R.sup.2 .times..sqroot.t.ltoreq.100000, and the total rolling reduction at temperature lower than the Ar3 transformation point is not lower than 60%. The hot-rolled steel sheet possesses a high level of Lankford value, and is free from cold-working embrittlement. The method may include the step of obtaining, after the rolling, pickling, annealing and hot dip galvaniz…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.