To provide a coated steel sheet in which, after ordinary hot dipping and coating/baking, yield elongation is suppressed to ≤3% to suppress deterioration in appearance due to the occurrence of buckling pattern and stretcher strain at bending.
A steel slab having a composition which consists of, by mass, 0.01 to 0.10% C, ≤0.3% Si, ≤0.5% Mn, ≤0.05% P, ≤0.02% S, ≤0.04% Al, ≤0.004% N, 0.0002 to 0.0020% B and the balance Fe with inevitable impurities and in which a relation between the contained N and B is regulated to a prescribed relation is subjected to hot rolling at 630 to 750°C hot rolling coiling temperature, and then the cold rolled steel sheet subjected to pickling and cold rolling is subjected to hot dipping treatment while regulating annealing temperature to 650 to 850°C, thereby producing a steel sheet for coating which has a structure having 20 to 80 μm ferrite grain size.
SUZAKI TSUNETOSHI
MATSUMOTO TAKASHI
Okada Manri
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