| 摘要 |
PROBLEM TO BE SOLVED: To provide a hot dip Al-Zn alloy plated steel sheet extremely excellent in corrosion resistance by executing chemical conversion treatment, coating or the like in general. SOLUTION: As to this invention, the fact that, in the case Zn condensed parts causing corrosion in a plating film are eliminated,β-Zn crystal grains are finely dispersed into an Al matrix to make the structure of dendrite parts and inter-dendrite parts the approximately same one, the electrochemical contact corrosion can be improved to obtain a plating film excellent in corrosion resistance has been found and, this is a hot dip Al-Zn alloy plated steel sheet contg. 20 to 95 wt.% Al in a plating film, in which the average grain size of theβ-Zn crystal grains present in the plating film is <=1/20 of the average plating film thickness, and they are dispersed without being mutually contacted.
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