| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to obtain a high-reliability joint in resistance welding, such as spot welding, by forming lower plating layers consisting of an Al material and upper plating layers consisting of a Cr material or Mo material on both sides of a steel sheet. SOLUTION: The lower plating layers 2 consisting of the Al or an alloy consisting essentially of the Al are formed on both sides of the steel sheet 1. The upper plating layers 5 consisting of the Cr or an alloy consisting essentially of the Cr or Mo or an alloy consisting essentially of the Mo are formed on the lower plating layers 2. The thickness of the lower plating layers 2 is substituted to >=5 to <=30μm and the thickness of the upper plating layers 5 to >=0.3 to <=5.0μm. When the welding of the steel sheets 1 to each other is executed by pressing welding electrodes 3 to the steel sheet surfaces via the upper plating layers 5 by spot welding, the reaction between the lower plating layers 2 and the welding electrodes 3 is suppressed and the wear of the front ends of the electrodes is extremely little. The diameter of a nugget 4 is kept constant and the strength of the supporting welding is kept nearly constant as well.
|
