초록 ▼

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 el

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 ≥2.8 and also exhibits the difference (rmax-rmin) between the maximum value rmax and the minimum value rmin satisfying the condition of (rmax-rmin)≤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°; conducting secondary cold rolling at a rolling reduction not smaller than about 30% so as to provide a total rolling reduction not smaller than about 78%; and conducting final annealing at a temperature which is between the recrystallization temperature and about 920°C.

대표청구항 ▼

A method of producing a cold-rolled steel sheet suitable for deep drawing, comprising: preparing a blank steel material having 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.

A method of producing a cold-rolled steel sheet suitable for deep drawing, comprising: preparing a blank steel material having 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; subjecting said material to a hot rolling; conducting primary cold rolling on said material at a rolling reduction not smaller than about 30%; conducting intermediate annealing on said material at a temperature ranging between the recrystallization temperature and about 920°; conducting secondary cold rolling on said material at a rolling reduction of not smaller than about 30% so as to provide a total rolling reduction not smaller than about 78%; and conducting final annealing on said material at a temperature which is between the recrystallization temperature and about 920°C.