METHOD FOR MANUFACTURING ZN-AL ALLOY COATED STEEL SHEET AND APPARATUS THEREOF

摘要

The present invention relates to a method for manufacturing a hot-dip galvanized steel sheet having excellent corrosion resistance and surface quality used in building interior/exterior materials and home appliances. The present invention is based on a Zn-Al-Mg-based zinc hot dip galvanizing bath used in manufacturing existing high anti-corrosive hot-dip galvanized steel sheet, and an Mg oxide is suppressed during a manufacturing process by adding a small amount of Ba to secure excellent corrosion resistance and surface quality. A Zn-Al alloy coated steel sheet undergoes plating in a plating bath including 92 to 95 wt% of zinc, 3 to 5 wt% of aluminum, 1 to 3 wt% of magnesium, 0.01 to 0.001 wt% of barium, and the balance of inevitable impurities to manufacture a Zn-Al alloy coated steel sheet having excellent surface and front end surface corrosion resistance and fine surface appearance. A Zn-Al alloy coated steel sheet having excellent corrosion resistance by forming an MgZn2 phase of an inter-metal compound due to an Mg component in a plated layer and excellent corrosion resistance and surface quality by preventing formation of an MgO oxide film in an upper portion of the plating bath due to addition of Ba can be manufactured.;COPYRIGHT KIPO 2016