Cold-rolled steel sheet for deep drawing and method of producing the same
US5041166A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 31, 1990 |
| Grant date | Aug 20, 1991 |
| Priority date | — |
| Expiry date | Aug 31, 2010 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D8/0473
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A cold-rolled steel sheet suitable for deep drawing has a composition containing up to about 0.005 wt % of C, up to about 0.1 wt % of Si, up to about 1.0 wt % of Mn, up to about 0.1 wt % of P, up to about 0.05 wt % of S, about 0.01 to 0.10 wt % of Al, up to about 0.005 wt % of N, one, two or more elements selected from the group consisting of about 0.01 to 0.15 wt % of Ti, about 0.001 to 0.05 wt % of Nb and about 0.0001 to 0.0020 wt % of B, and the balance substantially Fe and incidental impurities. The steel sheet exhibits a Lankford value (r-value) of about r.gtoreq.2.8 and also exhibits the difference (r.sub.max -r.sub.min) between the maximum value r.sub.max and the minimum value r.sub.min satisfying the condition of (r.sub.max -r.sub.min).ltoreq.about 0.5. The steel sheet is produced by a process having the steps of: conducting hot-rolling on the steel material of the above-described composition; conducting a primary cold rolling at a rolling reduction not smaller than about 30%; conducting intermediate annealing at a temperature ranging between the recrystallization temperature and about 920.degree.; conducting secondary cold rolling at a rolling reduction not smaller than ab…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.