SURFACE TREATED STEEL SHEET FOR ELECTRONIC EQUIPMENT PARTS

PURPOSE:To obtain a steel sheet for electronic equipment parts in which superior rust resistance and weldability are provided to one side and also superior rust resistance and whisker resistance are provided to the other side by plating one side of a steel sheet with Ni, Sn, and Zn, subjecting the other side to surface roughing and then to plating with Ni and Zn, exerting heating to alloy respective plating layers on the steel sheet surfaces, and further applying chromate treatment to the above layers. CONSTITUTION:One side of a steel sheet is subjected to surface working so that >0.4mu surface roughness Ra is reached, and then, this surface is plated with Ni by 0.05-0.10g/m coating weight and further plated, if necessary, with Zn by >=0.05g/m coating weight. Subsequently, the other side of the steel sheet is plated with Ni by >=0.05g/m coating weight, and further, a tinning layer in >=0.05g/m coating weight and also a galvanizing layer in a coating weight 10-80% of the coating weight of the tinning layer are formed on the above. After heating is carried out to convert the above plating layers into an Fe Ni alloy plating layer and a plating layer of the alloy of respective metals, respectively, chromate films are formed on both sides, respectively.