| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce sticking of sputter and welding soot around a nut onto a surface of a steel plate in projection welding without increasing time and labor of an operator. <P>SOLUTION: There is provided a projection welding method in which a nut 50 having a plurality of projections formed on a lower-end side is arranged at a screw hole part on a surface of a steel plate 100, and the nut 50 is welded onto the steel plate 100 while crushing the projections by electrically connecting a lower electrode 3A in contact with a rear surface of the steel plate 100 to an electrode tip 20 on a tip side of an upper electrode 2A in contact with an upper surface of the nut 50 and lowering the upper electrode 2A. In the welding, compressed air is jetted downward toward around the nut 50 on top surface of the steel plate 100, from a cylindrical gap formed between an inner peripheral surface of an electrode tip fitting hole 24 provided to a tip surface of an electrode tip holder 21 of the upper electrode 2A and an outer peripheral surface of the electrode tip 20 inserted into the electrode tip fitting hole, thereby reducing the sticking amounts of the sputter and welding soot onto the top surface of the steel plate 100. <P>COPYRIGHT: (C)2013,JPO&INPIT |
