| 摘要 |
PROBLEM TO BE SOLVED: To provide an easy-open lid which is easy in manufacture on the same level in the score technology as the conventional score method, and economically manufactured without any repair coating on a score part. SOLUTION: A surface-treated steel sheet having the composition consisting of, by weight, <=0.20% C, <=0.5% Si, <=1.0% Mn, <=0.15% P, <=0.100% S, <=0.150% soldering Al, <=0.0150% N, and <=0.070% B, and <=0.10% one or two or more Nb and Ti, as necessary, and the balance Fe with inevitable impurities, and having a resin film of 5-100μm in thickness on an outermost layer of front and back sides, is used, and the resin film is remained on the whole surface of the score groove without damaging the resin film by executing the score on inner and outer surfaces of a lid by a score blade in which the sectional shape of the score blade is arc-like, and its radius (R) is 0.050-0.300 mm.
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