| 摘要 |
PURPOSE:To obtain a product comprising a steel plate containing interposed substances such as Al, Si or the like segregated to a surface layer thereof to which stable and good galvanizing is applied by assembling an iron plating process between a degreasing or, further, picking process of a cold rolled steel plate and a heating process thereof in a reductive atmosphere. CONSTITUTION:An unwound steel strip receives degreasing and removal of an iron powder adhered to a surface thereof and is washed by water in a degreasing apparatus 9. When the removal of the iron powder or the like is insufficient, simple acid treatment is applied to said steel strip and washing is carried out in a pickling tank 11. Next, electroplating of iron is applied to the steel strip in an electrolytic treatment tank 13 but a thickness thereof is adjusted to 0.01-1.00mu. Said steel strip is washed by water and dried in an apparatus 15 and, after preliminarily heated in a heating furnace 2, further heated in a H2 containing gas atmosphere within a reductive annealing furnace 3. In this case, there is no cause of press flaw formation of the steel plate and, because surface clearing is simple, annealing is mainly carried out and reduction of a H2 concn. and shortening of a time are enabled. Subsequently, the steel strip is subjected to immersion zinc plating in a plating pot in a condition without contacting with the air and a plated product with good close adhesiveness is obtained. |
