| 摘要 |
PROBLEM TO BE SOLVED: To suppress powdering, to obtain excellent sliding characteristics and to effectively prevent the generation of slipping flaws by specifying the range of the content of iron in a plating layer with specified coating weight and the range of the center line average roughness in the plating layer. SOLUTION: The range of the content of iron in a plating layer of a hot dip galvannealed steel sheet with <=45 g/m2 plating coating weight is controlled to 11 to 15 wt.%. The range of the center line average roughness Ra in this plating layer is controlled to 0.5 to 0.8μm. After hot dip plating, alloying treatment or the like is applied. In the producing process of the plated steel sheet, based on the relation between the content of iron in the plating layer with the objective plating coating weight and the powdering properties, the upper limit of the iron content imparting good powdering properties is decided. Based on the relation between the iron content andζphase intensity, from theζphase intensity imparting good slidability, the lower limit of the iron content is decided. Based on the relation between the center line average roughness of the plating layer in the iron content at the lower limit and the slidability, the upper limit of the center line average roughness imparting good slidability is decided.
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