| 摘要 |
PROBLEM TO BE SOLVED: To stably produce a hot dip Al-Zn alloy plated steel sheet excellent in crack resistance and corrosion resistance without increasing the producing stage and adding special elements into a plating bath. SOLUTION: In the method for producing a hot dip Al-Zn alloy plated steel sheet in which, in continuous-type hot dip plating equipment, a steel sheet is annealed and is successively applied to hot dip plating in a hot dip Al-Zn plating bath contg. 20 to 95 wt.% Al, a steel sheet having surface roughness Ra (μm) satisfying the inequality of [(100+80CW)<1/2> -10]/40>=Ra in accordance with the coating weight CW (g/m<2> ) per side of the plated steel sheet to be produced is used as an original sheet, and the hot dip plating of 10 to 45 g/m<2> coating weight per side is applied. The plated steel sheet obtd. by this producing method has excellent crack resistance because of the reduced coating and moreover it has excellent corrosion resistance since the generation of spotlike rust in the pat subjected to severe working is suppressed.
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