PURPOSE: To remove easily the discoloring material on the non-plated surface of a one-side electrogalvanized steel sheet and to improve remarkably appearance of the non-plated surface by treating said surface with an aq. oxalic acid soln. to form the film of iron oxalate on the non-plated surface.
CONSTITUTION: The non-plated surface of a steel sheet electrogalvanized on one side is subjected to rinsing in succession to plating and is then treated in an aq. oxalic acid soln. or an aq. soln. mixture composed of oxalic acid and oxycarboxylic acid. The film of ≤0.1g/m2 iron oxalate is formed on the non-plated surface mentioned above. For example, lactic acid, tartaric acid, etc. are used as said oxycarboxylic acid. The good appearance is industrially easily on the non-plated surface of the one-side electrogalvanized steel sheet and at the same time temporary rust preventiveness and phosphotability are improved as well by the above-mentioned surface treatment (post treatment) of the non-plated surface.
FURUTA AKIHIKO
HONMA TOSHIYUKI
| JPS5837192A | 1983-03-04 | |||
| JPS52110242A | 1977-09-16 |