| 摘要 |
PURPOSE:To color the steel plate to a desired color tone in good reproducibility by a method wherein two steel plates to be colored to the desired color tone are immersed in a coloring liquid in such a manner that two of them are mutually contacted and surfaces thereof to be colored are respectively faced outwardly and the potential difference between the outer side surface and a reference electrode is measured. CONSTITUTION:Even if the finished surface of the stainless steel plate is different at a front surface and a back surface, said steel plate is colored to the desired color tone in good reproducibility. That is, the two steel plates are laid on upon another in such a manner that the surfaces thereof to be colored to a desired color tone are faced outwardly and immersed in a mixed aqueous solution of chromic acid and sulfuric acid or the like. The difference between the potential of the outwardly faced surfaces and that of a reference electrode (white electrode) immersed in the coloring liquid is measured. In the relation of this potential difference and a desired color tone, when the color tone is reached to a preliminarily determined value, said steel plates are withdrawn from the coloring liquid. |
