PROCESS FOR PHOSPHATIZING STEEL ZINC-COATED ON ONE SIDE ONLY

摘要

A process is disclosed for phosphatizing the zinc-coated surface of a steel strip electrolytically zinc-coated on one side only by a short spraying or immersion treatment with acid phosphatizing solutions which contain 1.0 to 6.0 g/l Zn2+ cations, 0.5 to 5.0 g/l Ni2+ cations and 14 to 25 g/l PO43 anions. The "free acid" content amounts to 3.5 to 8.0 points; the total acid content amounts to 22 to 40 points.