| 摘要 |
PURPOSE:To produce a steel plate which is coated with dissimilar metals on double sides and has high corrosion resistance by galvanizing a steel strip undercoated on one side with Fe, Ni, Co, Cu, Sn, etc. in a specific thickness range then applying an alloying treatment on the undercoating side. CONSTITUTION:After a steel strip is defatted and is removed of iron powder, the strip is pickled and is cleaned of surfaces; thereafter, single metal of Fe, Ni, Co, Cu, Sn or an alloy of >=2 kinds among said metals is undercoated on one side of the steel strip to 0.015-1.0mu thickness. Such steel strip is cleaned of surfaces by a gas reducing system or the like and then galvanized. The coating weight of zinc on the surface on the undercoated side is controlled in a state equal to or smaller than the coating weight on the other side, preferably to <=1/1.5 or more preferably <=1/3 said coating weight by gas wipers, and the plating is alloyed by heating in a 400-700 deg.C range, whereby the alloy coating layer is formed quickly and the good galvanized layer is obtained. |
