PURPOSE: To continue the annealing line and the surface treating line by coating a specific metal compound to a steel plate or applying a specific metal plating thereto prior to annealing in a treating line of thin steel plate.
CONSTITUTION: By forming the coating film on the steel plate by coating a compound or electroplating and forming a metal diffusion layer by annealing to enhance a corrosion resistance thereof, the continuation of a treating line is made possible because a surface treated film becomes thin. The coating compound is selected from one or more of Ni, Co, P compound and, for example, used at a concn. of 1W10% as an acetate. The electrolytic plating of Ni, Co, Sn or Cr is applied at 0.001W1μ thickness. The treated steel plate is immediately subjected heat treatment, for example, at 500W800°C to form the layer containing aforementioned metal diffused in the surface of the steel plate. This treated steel plate is immediately subjected to the skin pass and immersed in an aqueous solution containing Cr and/or P compound or subjected to electrolysis to form a nonmetallic Cr oxide layer or an oxide layer of a base metal.
OOYAGI YASHICHI
NAKANO HIROBUMI
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| JPS5290432A | 1977-07-29 | |||
| JPS5154010A | 1976-05-12 |