Design and function
Degaussing
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099-002065-EW501
9.9.2019
5.3 Degaussing
CAUTION
Movement forces due to electromagnetic fields!
Electromagnetic fields may exert movement forces on unsecured metal objects! This
may result in injury for example by tools that are set in motion uncontrolled, etc.
• Remove metal objects lying around from the working area or secure against movement.
5.3.1 Description of procedure
The degaussing of ferromagnetic workpieces in welding technology is intended to reduce arc deflection,
arc instability, uneven droplet detachment, spatter and irregular flank connections.
To degauss the workpiece successfully and demonstrably, the magnetic flux density must be measured in
millitesla (mT). This requires a field strength or magnetic flux density meter.
This device offers two methods for degaussing a workpiece:
• Method degauss - degaussing the workpiece before welding.
With this method, an alternating magnetic field is applied to the component. The magnetic field de-
creases with each change of polarity (+/-) ensuring that the workpiece can be completely degaussed
along the hysteresis curve.
It does not make economic sense to completely degauss long components such as pipes. In this case,
the remaining magnetic field moves towards the degaussed area and we recommend using the activ-
gauss method.
• Method activgauss - generating an opposing magnetic field during welding.
With this method, an adjustable direct current generates an opposing magnetic field. The opposing
magnetic field is applied during the welding process and counteracts the magnetism present in the
workpiece. This reduces arc deflection (arc instability) irregular droplet detachment, spatter and irregu-
lar flank connections.
When using the activgauss method, only the magnetic fields in which the opposing field is identical are
compensated. The magnetic field along the welding joint is usually not constant. This means that in
practical use the field around the welding start should be compensated. The welder begins to weld. If
the arc becomes unstable, the magnetic flux density must be measured and re-compensated. Conti-
nue until the pipe root welding is complete. Experience has shown that this process must be carried
out 3 to 4 times over the circumference. As the root welding progresses, the existing magnetic field
decreases to 0.
