Fastening element attaching holed sheet metal workpiece to bolt welding unit

摘要

The fastening element (1) in the form of a hollow cylinder with internal thread attachable to a previously holed sheet metal workpiece (3) by means of arc welding with stroke ignition is characterised by the presence of a chamfer (1c) running at an acute angle to the outer surface of the element. As a consequence a magnetic field generated by a ring winding (7), a circumferential arc is produced between the circular edge of a hole (3a) and the chamfered end of the fastening element. At the same time, a protective gas suited to the materials being joined is applied to the welding zone via the inlet openings (5b) in a plastic pipe (5) located between the bolt holder (2) and the spindle (4) of the welding unit.