| 摘要 |
PURPOSE:To stably manufacture the titled steel sheet by successively subjecting a steel sheet to Ni-Fe alloy electroplating, tinning, melting by heating and chromating under specified conditions. CONSTITUTION:An aqueous soln. of 1.0-3.0 pH contg. 30-120g/l Ni and Fe ions in a weight ratio represented by formula I, 45-160g/l in total of 20-120g/l Cl<-> and SO4<-->, <=0.5g/l Fe<++>, and 10-50g/l H3BO3 is prepd. A soluble electrode consisting of metallic Ni and Fe is immersed in the soln. and a steel sheet is electroplated with an Ni-Fe alloy having 10-30% Ni content by 50-500mg/m<2> per one side. The percentage (by area) of Ni in the electrode is represented by formula II. The electroplated steel sheet is washed and tinned by 500-2,500mg/m<2> per one side. After the resulting tin layer is melted by heating, a chromate layer is formed by 5-50mg/m<2> per one side.
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