| 摘要 |
PURPOSE: A chemically processed steel sheet remarkably improved in corrosion resistance by generating a converted layer, which contains both soluble and scarcely-soluble metal compounds, with a self-repairing faculty on an Al-Si alloy plating layer formed on a steel base is provided. CONSTITUTION: The chemically processed steel sheet comprises a steel base coated with an Al-Si alloy plating layer, and a converted layer, which contains both of at least one scarcely-soluble compound and at least one soluble manganese or titanium compound, generated on a surface of the plating layer, wherein the Al-Si alloy plating layer has Si content adjusted to 5-13 mass % Si as a whole and to 7-80 mass % at its surface, wherein the Al-Si alloy plating layer has the rugged surface that Si-rich particles are distributed as convex parts thereon, wherein the scarcely-soluble compound is titanium oxide, hydroxide or phosphate, and the soluble compound is manganese oxide, hydroxide or fluoride, the converted layer is composed of an oxide, hydroxide or phosphate of a valve metal as the scarcely-soluble compound and a fluoride of a valve metal as the soluble compound, wherein the valve metal is selected from Ti, Zr, Hf, V, Nb, Ta, Mo and W, the converted layer contains the oxide or hydroxide and the fluoride at an F/O atomic ratio not less than {fraction (1/100)}, the converted layer further contains one or more of soluble or insoluble metal phosphates and complex phosphates, and the converted layer further contains at least a lubricant. |
