HBS 93-20-270, Operating Manual, Page: 27 / 66

A 12 Order No. BA 93-20-270 Issue 01.03.08 27
The shielding gas influences
– the arc and the melting behavior of welding element and workpiece,
– the development of the weld collar and the penetration shape via the surface tension.
With stud welding with shielding gas, the shape of the weld collar is not reproducible,
as the shielding gas has no forming effects on the melt – different from a ceramic ferrule.
And so an additional ceramic ferrule may be used in special cases.
The standard welding elements and ceramic ferrules for drawn-arc stud welding are
described in several standards (see appendix). Welding elements with cone-shaped
front area and without an aluminum ball are preferably used.
Studs with cone-shaped front area preferably used under shielding gas.
With shielding gas, you should only weld in position PA (verti-
cal) because due to gravity, the shielding gas cannot prevent
flow of the molten metal.
5.2.3 Short-Cycle Drawn-Arc Stud Welding with Shielding Gas
Short-cycle drawn-arc welding with shielding gas is used for welding elements within a
diameter range of 3 to 12 mm (nominal diameter without flange) and welding times
between 5 and 100 ms.
Due to the short welding times, the energy input and the weld pool are so small that also
welding elements up to 12 mm diameter can be welded on thin workpieces.
Normally, welding elements with flange (according to current standards, see appendix)
are used, which forms a larger welding area compared with the shaft diameter. In this
way, higher tensional forces than in the stud shaft can be transmitted in spite of some
pores in the weld zone. To minimize pore formation, the use of shielding gas for stud
diameters upwards of 8 mm is recommended.