MOLTEN Al-Zn-Mg-Si-PLATED STEEL SHEET AND MANUFACTURING METHOD THEREFOR

摘要

The purpose of the present invention is to provide a molten Al-Zn-Mg-Si-plated steel sheet having favorable corrosion resistance of the flat parts and edges and also having excellent machined part corrosion resistance. To achieve said purpose, the present invention is a molten Al-Zn-Mg-Si-plated steel sheet having a plated coating on the surface of a steel sheet and is characterized in that: the plated coating is obtained from an interfacial alloy layer present at the interface with the base steel sheet and a main layer present on said alloy layer; the coating contains 25-80 mass% of Al, greater than 0.6-15 mass% of Si, and greater than 0.1-25 mass% of Mg; and the content of Mg and Si in the plated coating satisfies formula (1). MMg/(MSi−0.6)>1.7 (1) MMg: Mg content (mass%), MSi: Si content (mass%)