METHOD FOR MANUFACTURING ELECTRO-GALVANIZED STEEL SHEET HAVING GOOD CORROSION RESISTANCE AND SURFACE HARDNESS

摘要

PURPOSE: A method for manufacturing an electro-galvanized steel sheet is provided to improve corrosion resistance and hardness of plating layer during electro-galvanizing by performing plating after adding a proper amount of solution comprising Fe and W to a galvanizing bath based on chlorides. CONSTITUTION: The method for manufacturing an electro-galvanized steel sheet having good corrosion resistance and surface hardness is characterized in that plating is performed by adding a solution prepared by mixing the dissolved solutions after dissolving iron chloride and sodium tungstenate into water with a ratio of Fe to W being 1:0.05 to 1:3 to the plating bath so that the total sum of the two metals Fe and W is 0.01 milli mole to 0.1 mole when performing electro-galvanizing in an acidic chloride based electro-galvanizing bath. The electro-galvanizing solution for chloride bath is prepared by adding a solution prepared by mixing the dissolved solutions after dissolving iron chloride and sodium tungstenate into water with a ratio of Fe to W being 1:0.05 to 1:3 in an acidic chloride based electro-galvanizing bath to the plating bath so that the total sum of the two metals Fe and W is 0.01 milli mole to 0.1 mole.