| 摘要 |
PURPOSE: To produce a precoated steel sheet excellent in corrosion resistance, at the time of coating the surface of a steel sheet with an Al-Cr plating layer contg. a specified amt. of Cr, a chemically treated layer and a coating material in succession, by specifying the structure of the Al-Cr plated layer. CONSTITUTION: On the surface of a steel sheet, an Al-Cr plating layer contg., by weight, 1 to 20% Cr is formed by a vapor deposition plating method, and the plating layer constituted by a structure contg. an Al phase in which Cr is allowed to enter into solid solution and Al13 Cr2 as an intermetallic compound is obtd. On the surface of this plating layer, a chemically treated layer of chromic acid series, zinc phosphate series or the like is formed, and the surface of this chemically treated layer is furthermore coated with a coating material of polyester series, acrylic series, urethane series or the like. Thus, the precoated steel sheet in which corrosion is hard to occur in the cutting edge faces, thus, corrosion resistance is excellent and the blistering of the coating film from the cutting edge faces is hard to generate, can be obtd.
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