PRODUCTION OF STEEL SHEET ELECTROPLATED ON ONE SIDE

摘要

PURPOSE:To improve the suitability to chemical conversion of both sides in the production of a steel sheet electroplated on one side wherein electroplating is applied thinly on the non-plating side as well and is thereafter removed by reverse current by conducting slight current on the plating side or maintaining said side under no current. CONSTITUTION:A steel strip 1 which is subjected to defatting, pickling and washing is passed in a plating cell 5. Strong current is conducted to a lower anode 13 with the strip 1 as cathode and weak current to an upper anode 12, and thin plating is applied on one side of the steel strip. The strip is passed in a treating cell after washing. An indirect current conduction method wherein the thin plating layer atop the strip 1 is removed by conducting current between a lower anode 18 and an upper cathode 17 and plating is applied on the bottom surface as well by weak current is executed or a direct conduction method wherein strong current is conducted between the strip 1 and the cathode 17 through a roll 19 and weak current is conducted between the strip 1 and the anode 18 is executed in the treatment cell. A method wherein the anode 18 is omitted is equally good. The suitability to chemical conversion of the strip 1 is improved by such method. The indirect current conduction method requires high voltage and makes cost high and therefore the direct current conduction method is preferred.