Steel sheet for can lid and method for producing the same (as amended)

Abstract

A steel sheet for can lids contains, in mass %, 0.020-0.060% of C, 0.01-0.05% of Si, 0.20-0.60% of Mn, 0.001-0.100% of P, 0.008-0.020% of S, 0.0130-0.0190% of N, and from 0.005% to {−4.20×N+0.110}% of Al, with Mnf being 0.30% to 0.58% (inclusive), where Mnf=Mn−1.7×S, and with the balance made up of Fe and unavoidable impurities. The lower yield strength YP (N/mm 2 ) and the yield point elongation YPEl (%) of this steel sheet for can lids after an aging treatment at 210° C. for 10 minutes satisfy YP≥355, YPEl≥2, YPEl≥(60/(YP−355))+2 and YP≤4.09×YPEl+476. A method for producing this steel sheet for can lids.

1 . A steel sheet for a can lid, comprising, in terms of % by mass:
 C: 0.020% to 0.060%;   Si: 0.01% to 0.05%;   Mn: 0.20% to 0.60%;   P: 0.001% to 0.100%;   S: 0.008% to 0.020%;   N: 0.0130% to 0.0190%; and   Al: 0.005% to {−4.20×N+0.110}% (where N in the formula represents an N content (% by mass) in steel),   wherein, when Mnf=Mn−1.7×S (where Mn and S in the formula respectively represent an Mn content (% by mass) and a S content (% by mass) in the steel), Mnf is 0.30% or more and 0.58% or less,   the balance is Fe and unavoidable impurities, and   after 210° C.×10 minutes of an aging treatment, a lower yield strength YP (N/mm 2 ) and a yield point elongation YPEl (%) satisfy YP≥355, YPEl≥2, YPEl≥(60/(YP−355))+2, and YP≤4.09×YPEl+476.   
     
     
         2 . A method for producing the steel sheet for a can lid according to  claim 1 , comprising:
 re-heating a steel slab to a temperature of 1150° C. or higher;   hot-rolling the re-heated steel slab at a coiling temperature of 680° C. or lower to produce a hot-rolled steel sheet;   cold-rolling the hot-rolled steel sheet to produce a cold-rolled steel sheet;   recrystallization-annealing the cold-rolled steel sheet; and   temper-rolling the resulting steel sheet at an elongation of 3% or less.