| 摘要 |
PROBLEM TO BE SOLVED: To produce a hot dip metal coated steel sheet excellent in roll- formability hardly developing both pocket waves and periodical wavy defects and fluting and to provide a producing method by which this steel can be produced at a low cost. SOLUTION: This hot dip metal coated steel sheet is composed of a steel sheet having the composition consisting of <=0.12% C, <=0.10% Si, 0.10-2.00% Mn, <=0.10% P, 0.0050-0.0200% N, <=0.100% Al and the balance Fe with inevitable impurities, and the structure of >=10.0μm average crystal grain diameter, and a plating layer coating this steel sheet, and has <=6.0% yield elongation. The hot dip coated steel sheet is produced by successive processes of hot-rolling, cold-rolling, annealing, plating and leveller working, in this order. In these processes, it is important to regulate the FDT in the hot-rolling to lower than the Ar1 transformation point and the elongation ratio in the leveller working after plating to >0.3% to 2.0%.
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