| 摘要 |
PROBLEM TO BE SOLVED: To manufacture metallic parts composed of a stainless steel by welding without damaging a passive state film of the surface. SOLUTION: This spot welding machine comprises a pair of electrodes 5, 11 arranged to be capable of approaching/separating each other, supply means 13, 17 to supply an inert gas in an area between the electrodes, and a control means to control the current conducting and the supply of the inert gas between a pair of the electrodes 5, 11. The control means stops the supply of the inert gas after a given time passes from the stop of the current conducting. Thus, after the workpiece is cooled to the temperature not to be oxidized in the air, machine parts in a good surface condition are obtained without damaging a passive state film on the surface even when the workpiece is exposed to the air in an oxidization atmosphere. Further, since the machine parts do not require a special surface treatment such as plating and the like, as a whole, the manufacturing cost of the metallic parts with a welding structure can be reduced. |
