ANTICORROSIVE OVERLAP-COATED IRON OR STEEL MATERIAL CHROMATE TREATED PLATED STEEL

摘要

ANTICORROSIVE OVERLAP-COATED IRON OR STEEL MATERIALAbstract of the DisclosureAnticorrosive overlapped coatings so far employed forsuch iron and steel materials as plates, pipes, bars orwires are formed by electroplating an Sn base - Zn alloylayer on the surface of the iron or steel material andapplying a chromate-treatment to the alloy layer. How-ever, this requires a long time for the formation of aplated layer of a suitable thickness, and consequentlya reduction of the plating time together with a furtherimprovement of the anticorrosive effect is desired. Thepresent invention has succeeded in making it possible toreduce the plating time while improving the anticorrosioneffect and in improving the productivity by forming theelectroplated layer of an Sn base - Zn alloy directly, orover an electroplated layer of Zn, on the surface of theiron or steel material, then forming an electroplatedlayer of Zn on the layer of the alloy, and further apply-ing a chromate-treatment on the Zn layer.