CHROMATE METHOD OF ELECTROGALVANIZED STEEL SHEET FOR IMPROVING BLACKENING RESISTANCE

摘要

PURPOSE: A method for preventing chromate film of electrogalvanized steel sheet from being blackened under humid and high temperature conditions is provided. CONSTITUTION: In a method for coating electrogalvanized steel sheet with chromate solution, the method is characterized in that 3-methyl-5-pyrazoline is added to the chromate solution in an amount of 2 to 10 g/L.