Zn-Mg-Al Manufacturing Method of Film Laminate Steel Sheet Using Ground Zn-Mg-Al Coating Sheet Having High Corrosion Resistance and Steel Sheet Using the Same

摘要

The present invention relates to a method for manufacturing a film-laminated steel sheet using a material grinding a Zn-Mg-Al-based high corrosion resistant plated steel sheet, and a steel sheet manufactured thereby, and the objective of the present invention is to improve corrosion resistance of a cut or processed part by using the Zn-Mg-Al-based high corrosion resistant plated steel sheet as a material. According to the present invention, the method comprises: a step (S10) of forming a hairline layer (20) on a surface of a base steel sheet (10); a step (S20) of forming a pretreatment layer (30) on the hairline layer (20) and the lower part of the base steel sheet (10); a step (S30) of coating a coating composition on an upper pretreatment surface (30) to form an upper coating layer (40); a step (S40) of coating a coating composition on a lower pretreatment layer (30) to form a lower coating layer (60); and a step (S50) of laminating a film on the upper coating layer (40). The base steel sheet (10) is a Zn-Mg-Al-based alloy comprising: 94 to 98 wt% of Zn; 1 to 4 wt% of Mg; 0.1 to 15 wt% of Al; and the remainder of inevitable impurities. In the step (S10), the base steel sheet (10) passes through a roll including sandpaper rotated at the speed of 1,000 to 3,500 RPM for a hairline or a predetermined pattern to be formed on a surface of the base steel sheet (10).