| 摘要 |
PROBLEM TO BE SOLVED: To provide an automotive Al series plated steel sheet excellent in corrosion resistance, workability, weldability and recycling properties. SOLUTION: In this automotive Al series plated steel sheet, the surface of a steel sheet is provided with an Al series plated layer containing, by mass, 3 to 9% Mg, 6 to 10% Si, and the balance Al with inevitable impurities by 10 to 100 g/m2 per side, an oxidized film layer essentially consisting of Mg on the surface of the Al series plated layer is controlled to 20Åor less, and the upper layer thereof is provided with a zinc phosphate film layer containing zinc and phosphorus in a weight ratio (zinc/phosphorus) of 2.3 to 3.2 by 0.3 to 2.5 g/m2, and, in the case the Al series plated layer is observed by cross-sectional gradient polishing of 5 deg., a lumpy Mg2Si phase in which the longest side is 5 to 100μm is contained in the plated layer by 0.5 to 30% in an area fractional ratio. In place of the zinc phosphate film layer, an organic resin film layer of 0.3 to 3μm containing a high polymer solid lubricant of 1 to 20 mass% to the total content of the organic resin and the high polymer solid lubriacant may be adopted.
|
