Steel sheet for two-piece can and manufacturing method therefor

Abstract

A steel sheet for two-piece cans is suitable not only for drawing and ironing, but also for forming beads or geometric shapes on a can body and can be preferably used to form a special-shaped two-piece can. The steel sheet for two-piece cans contains, in mass %, C: 0.020% to 0.080%, Si: 0.04% or less, Mn: 0.10% to 0.60%, P: 0.02% or less, S: 0.015% or less, Al: 0.010% to 0.100%, and N: 0.0005% to 0.0030%, the balance being Fe and unavoidable impurities. The steel sheet has a tensile strength of 480 MPa or more, an elongation of 7% or more, a yield elongation of 3% or less, and a ferrite grain size of less than 6 μm.

1 - 3 . (canceled) 
     
     
         4 . A steel sheet for two-piece cans, comprising, in mass %, C: 0.020% to 0.080%, Si: 0.04% or less, Mn: 0.10% to 0.60%, P: 0.02% or less, S: 0.015% or less, Al: 0.010% to 0.100%, and N: 0.0005% to 0.0030%, the balance being Fe and unavoidable impurities,
 wherein the high-strength steel sheet has a tensile strength of 480 MPa or more,   an elongation of 7% or more,   a yield elongation of 3% or less, and   a ferrite grain size of less than 6 μm.   
     
     
         5 . The steel sheet for two-piece cans according to  claim 4 , further comprising, in mass %, B: 0.0001% to 0.0030%. 
     
     
         6 . A method of manufacturing the steel sheet for two-piece cans according to  claim 4  comprising:
 heating a slab to a heating temperature of 1,130° C. or higher; 
 hot rolling the slab subjected to the heating under a condition of a hot rolling finishing temperature of 820 to 930° C. to obtain a hot-rolled sheet; 
 coiling the hot-rolled sheet obtained in the hot rolling at a coiling temperature of 640° C. or lower; 
 pickling the hot-rolled sheet subjected to the coiling; 
 subjecting the pickled hot-rolled sheet to primary cold rolling under a condition of a rolling reduction of 85% or more to obtain a cold-rolled sheet; 
 subjecting the cold-rolled sheet obtained in the primary cold rolling to continuous annealing under an annealing temperature of 620° C. to 690° C. to obtain an annealed sheet; and 
 subjecting the annealed sheet obtained in the continuous annealing to secondary cold rolling at a rolling reduction of 6 to 20%. 
 
     
     
         7 . A method of manufacturing the steel sheet for two-piece cans according to  claim 5  comprising:
 heating a slab to a heating temperature of 1,130° C. or higher; 
 hot rolling the slab subjected to the heating under a condition of a hot rolling finishing temperature of 820 to 930° C. to obtain a hot-rolled sheet; 
 coiling the hot-rolled sheet obtained in the hot rolling at a coiling temperature of 640° C. or lower; 
 pickling the hot-rolled sheet subjected to the coiling; 
 subjecting the pickled hot-rolled sheet to primary cold rolling under a condition of a rolling reduction of 85% or more to obtain a cold-rolled sheet; 
 subjecting the cold-rolled sheet obtained in the primary cold rolling to continuous annealing under an annealing temperature of 620° C. to 690° C. to obtain an annealed sheet; and 
 subjecting the annealed sheet obtained in the continuous annealing to secondary cold rolling at a rolling reduction of 6 to 20%.