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

摘要

Provided is a steel sheet having excellent surface roughening resistance and a manufacturing method thereof. The steel sheet for cans contains 0.0040 to 0.01% C and 0.02 to 0.12% Nb. An average ferrite grain size in a cross section in the rolling direction in a region ranging from a surface layer of the steel sheet to a position 1/4 of a sheet thickness away from the surface layer of the steel sheet is set to 7 µm or more and 10 µm or less, and the average ferrite grain size in a cross section in the rolling direction in a region ranging from the position 1/4 of a sheet thickness away from the surface layer of the steel sheet to a sheet thickness center portion of the steel sheet is set to 15 µm or less. The average ferrite grain size in the cross section in the rolling direction in the region ranging from the surface layer of the steel sheet to the position 1/4 of a sheet thickness away from the surface layer of the steel sheet is set smaller than the average ferrite grain size in the cross section in the rolling direction in a region ranging from the position 1/4 of a sheet thickness away from the surface layer of the steel sheet to the sheet thickness center portion of the steel sheet. The steel sheet for cans is obtained by cooling a steel sheet at 50 to 100°C/s within 1 second after final finish rolling, is wound at 500°C to 600°C, is subsequently subjected to pickling treatment, is subjected to cold rolling at a reduction rate of 90% or more, and is subjected to continuous annealing at a temperature of equal to or more than a recrystallization temperature to 800°C or below.