PRODUCTION OF ELECTROGALVANIZED STEEL SHEET HAVING EXCELLENT WELDABILITY

摘要

PURPOSE:To improve weldability by heating a galvanized steel sheet in an oxidizing atmosphere under specific conditions to form an oxide film thereon. CONSTITUTION:A galvanized steel sheet is heated for >=30sec at 50-200 deg.C in an atmosphere in which >=1% oxygen exists to form an inert film centering at the oxide on the surfase of the plating layer. Water is sprayed onto the surface of the steel sheet during heating or steam is blown into the heating furnace to improve the effect of the above-mentioned heat treatment.