A surface-treated steel strip with improved welding and capable of coating properties and its production.

摘要

PURPOSE:To offer zinc or zinc alloy galvanized steel sheet excellent in weldability. And to produce stably zinc base electroplated steel sheet free from unplated part and incomplete adhesion and zinc galvanized steel sheet and zinc alloy galvanized steel sheet having alloyed layer free from unplated part and line texture even in the case of steel plate unsuitable for plating. CONSTITUTION:The steel sheet excellent in weldability is a steel sheet consist of the steel sheet adhered with zinc plated layer or zinc alloy plated layer onto at least one face of dead soft steel and having Fe-C plated layer or C concentrated layer formed by diffusion of Fe-C plated layer between the above- mentioned plated layer and base of the steel sheet. After executing Fe-C base plating with 0.01-10g/m2 amount of adherence on to steel sheet and =10wt.% carbon content, selectively annealing to obtain zinc electroplated and zinc galvanized or zinc alloy galvanized steel sheet respectively.