SURFACE TREATED STEEL MATERIAL WHICH IS EXCELLENT IN CORROSION RESISTANCE AND WATER RESISTANT ADHESIVE PROPERTY AFTER COATING

摘要

PURPOSE:To obtain a surface treated steel material which is excellent in both its corrosion resistance and water resistant adhesive property after coating, by providing a Zn-Ni alloy electroplating layer containing Ni of a prescribed ratio, on a steel base body, and providing an Fe electroplating layer on said layer. CONSTITUTION:As the first layer on a steel base body, a Zn-Ni alloy electroplating layer whose Ni content is 7-15wt% is formed so as to be = about 10g/m2. Subsequently, on said first layer, an electroplating layer of an Fe-Zn alloy containing =40wt% Fe or Zn is formed. In this regard, as for Fe and Fe-Zn alloy plating of the second layer, it is also possible to contain a small quantity (=20wt%) of other Ni, Co and Mn. A surface treated steel material obtained resultantly has said characteristics, therefore, it can be used sufficiently as a both surface rust preventing steel plate for an automobile.