| 摘要 |
PURPOSE:To improve the appearance and chemical convertibility of a non- plating surface by conducting a steel plate which is thinly plated on the non- plating surface,with the non-plating surface as an anode, into a vertical type electrolytic cell and forming a passive film thereon while removing the thin plating therefrom. CONSTITUTION:The steel plate subjected to the thin plating for protection on the non-plating surface is conducted to a current conducting roll 12 and electricity is conducted to the roll to make positive the steel plate. Such steel plate is fed to the vertical type electrolytic cell 10. Liquid blowing nozzles 17, 18 are installed in the cell 10 to exert forcible convection to the plating liquid by a pump. The thin plating for protection on the non-plating surface is removed by the electrolytic effect from the non-plating surface of the steel plate and the passive film is formed thereon in the stage when the steel plate passes through the space between down pass side cathodes 15 and up pass side cathodes 16 as counter electrodes. The gaseous H2 generated from the counter electrodes 15, 16 and the gaseous O2 generated when the steel plate is passive generate the ascending flow by themselves and do not stagnate between the electrodes 15, 16 and the steel plate.
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