MANUFACTURE OF STEEL SHEET COATED WITH LEAD-TIN ALLOY EXCELLENT IN CORROSION RESISTANCE

摘要

PURPOSE:To improve corrosion resistance, by acid pickling a steel steet precoated with Ni, Co or these alloy with hydrochloric acid, washing it with water, and then hot-dip coating it under a wet condition as such with a Pb-Sn alloy. CONSTITUTION:The surface of a steel sheet having said surface clarified is electroplated with Ni, Co or these alloy. This coated steel sheet is washed with water and then acid pickled with hydrochloric acid. Alternatively, the coated steel sheet may be further washed with water and then treated with an aqueous solution containing a chloride. The steel sheet under a wet condition after being subjected to said pretreatment is hot-dip coated with a Pb-Sn alloy. Hence, corrosion resistance is improved.