METHOD FOR MANUFACTURING AL-ZN BASED HOT DIP PLATED STEEL SHEET HAVING EXCELLENT SURFACE APPEARANCE AND PAINTABILITY

摘要

Disclosed is a method to manufacture an Al-Zn based plated steel sheet with excellent appearance and paintability. A method to manufacture the Al-Zn based plated steel sheet with excellent appearance and paintability, which is one aspect of the present invention, comprises: a step of preparing the Al-Zn based plating bath comprising 35-55 wt% of zinc (Zn), 0.5-3.0 wt% of silicon (Si), and the remainder consisting of aluminum (Al) and inevitable impurities; a step of manufacturing the Al-Zn based plated steel sheet by dipping and plating steel sheet based material into the Al-Zn based plating bath; and a step of cooling the molten Al-Zn based plated steel sheet. In the cooling step, an aluminum powder of which a grain size of 18-32 μm is injected to a surface of the molten Al-Zn based plated steel sheet at a speed of 40-80 g/m^2/min.