| 摘要 |
<p>The welding zone is fed with the protective gas; and this gas together with the surrounding air is removed from the welding zone by suction. In the pref. pistol, the stud holder is surrounded by a tube employed to blow pressurised protective- or inert- gas into the welding zone to remove air prior to the start of the welding operation. Located concentrically round tube is an outer tube connected to a suction appts. The bottom end of the outer tube is pref. fitted with a sealing ring pressed against the workpiece so all air can be removed and the inert gas atmos. maintained before, during, and after welding. All N2, O2 etc. is removed from the welding zone so completely sound welds free from porosity can be obtd.</p> |
