| 摘要 |
PURPOSE: To obtain a steel sheet excellent in pressable property in a steel sheet provided with a chemical film on the surface of a plated steel sheet, a lubricating layer as a second layer formed by applying a water-base lubricating material contg. a lubricant and baking the material and a surface lubricating layer as a third layer by specifying the component, coating weight, composition, thickness, etc., of each layer. CONSTITUTION: This surface-treated steel sheet consists of a thin steel sheet 1, a plating film 2 on the steel sheet, a chemical film 3 of chromate or phosphate, a lubricating film 4 and a surface lubricating layer 6, and a lubricant 5 is dispersed in the lubricating layer 4. Each film can be formed on one or both sides, and the thickness on the front and rear and composition of each film can be changed in accordance with its use. For example, the lubricating film consists of resin, silica and polyolefin wax and has 0.3-5.0μm thickness, the coating weight of the chemical film is controlled to 5-100mg Cr/m<2> or 0.2-2.0g phosphate/m<2> , the plating film consists of Zn, Zn alloy, Al or Al alloy, and coating weight is adjusted to 5-200g/m<2> . The baking of the lubricating coating material is started at least 4sec after coating.
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