COLD ROLLED STEEL SHEET WITH SUPERIOR SUITABILITY TO PHOSPHATING AND MANUFACTURE

摘要

PURPOSE:To improve the suitability of a cold rolled steel sheet to phosphating by depositing an Ni layer of a specified thickness and a Zn layer of a specified thickness on each of the surfaces of the steel sheet. CONSTITUTION:A cold rolled steel sheet is subjected to short-time cathodic electrolysis in a Zn plating bath to deposit a Zn layer by 0.001-0.01g/m<2>, and the steel sheet is subjected to short-time Ni plating in an Ni plating bath to deposit an Ni layer by 0.001-0.1g/m<2>. The Ni plating may be carried out by electrolysis or electroless substitution plating. An Fe layer may be deposited by 0.001-1g/m<2> in place of the Zn layer. The electrodeposition is suitably applied to the steel sheet after pickling or continuous annealing.