VERFAHREN ZUR HERSTELLUNG EINES KALT GEWALZTEN STAHLBANDES, DAS HOCHEMPFINDLICH IST FUER EINE UMWANDLUNGSBEHANDLUNG.

摘要

A cold rolled steel strip having an excellent conversion coating property is produced by a process comprising: anodic electrolytically treating at least one non-plated surface of a cold rolled steel strip to form a layer of oxides thereon, and cathodic electrolytically treating the above-mentioned surface to remove a portion of the oxide layer to an extent that the remaining portion of the oxide layer is in an amount corresponding to a quantity of electricity of from 0.05 to 4.0 millicoulomb/cm2 which is necessary to completely remove the remaining portion of the oxide layer by means of a cathodic electrolytic treatment in an aqueous solution containing 19.06 g/l of borax and having a pH of 6.4 at a constant current density of 5 microampere/cm2 and is in the form of a number of separate dots corresponding to a natural reduction time of from 1.0 to 200 seconds.