Highly corrosion resistant Zn-Al-Mg-Si alloy-plated steel material and process for its production

摘要

A Zn-Al-Mg-Si alloy-plated steel material with excellent corrosion resistance, characterized by comprising, in terms of wt%, Al: at least 45% and no greater than 70%, Mg: at least 3% and less than 10%, Si: at least 3% and less than 10%, with the remainder Zn and unavoidable impurities, wherein the Al/Zn ratio is 0.89-2.75 and the plating layer contains a bulky Mg2Si phase; also, a Zn-Al-Mg-Si alloy-plated steel material with excellent corrosion resistance, characterized by comprising, in terms of wt%, Al: at least 45% and no greater than 70%, Mg: at least 1% and less than 5%, Si: at least 0.5% and less than 3%, with the remainder Zn and unavoidable impurities, wherein the Al/Zn ratio is 0.89-2.75 and the plating layer contains a scaly Mg2Si phase.