| 摘要 |
PROBLEM TO BE SOLVED: To produce a steel sheet excellent in plating adhesion by executing dip pickling or, preferably, executing electrolytic pickling by the electric quantity equal to or above a specified one with a pickling soln. added with a specified amt. of thiourea and then executing electrogalvannealing of a Zn alloy. SOLUTION: Dip pickling or, preferably, electrolytic pickling is executed by the electric quantity of >=30 c/dm2 with a pickling soln. added with 15 to 500 ppm thiourea. The Zn alloy is the one contg. one or more kinds among Co, Fe, Ni, Cr and Mn, and preferably is a composite Zn alloy contg. these by 0.01 to 10 wt.% in total and a high molecular organic matter composed of C, H and O of 0.01 to 10 wt.% by the C content. The high-molecular organic matter composed of C, H and O is dextrin, dextran or at least one kind of organic compd. of high molecular weight having the effect equal to that of these and/or an organic compd. of high molecular weight produced therefrom by the reaction of decomposition, polymerization, or the like, at the time of electroplating.
|
