STEEL SHEET FOR CANS HAVING EXCELLENT SURFACE ROUGHENING RESISTANCE, AND METHOD FOR PRODUCING SAME

摘要

Disclosed are: a steel sheet for cans, which has excellent surface roughening resistance; and a method for producing the steel sheet for cans. The steel sheet for cans contains 0.0040-0.01% of C and 0.02-0.12% of Nb. The average ferrite crystal grain size in a cross-section in the rolling direction from the steel sheet surface to 1/4 of the thickness of the sheet is 7-10 µm (inclusive), and the average ferrite crystal grain size in a cross-section in the rolling direction from 1/4 to the center of the thickness of the sheet is 15 µm or less. In addition, the average ferrite crystal grain sizes satisfy the following relation: (the average ferrite crystal grain size in a cross-section in the rolling direction from the steel sheet surface to 1/4 of the thickness of the sheet) < (the average ferrite crystal grain size in a cross-section in the rolling direction from 1/4 to the center of the thickness of the sheet). The steel sheet for cans can be obtained by cooling a steel sheet at 50-100°C/s within 1 second after the final finish rolling, winding up the thus-cooled steel sheet at 500-600°C, subjecting the thus-wound steel sheet to pickling, cold-rolling the resulting steel sheet at a draft of 90% or more, and subjecting the thus-rolled steel sheet to continuous annealing at a temperature not less than the recrystallization temperature but not more than 800°C.