Wandering of a DC arc caused by unbalanced magnetic fields from current flowing in the work, residual magnetism in the steel or the placement of the ground. It is worst at joint ends, in corners and on magnetized pipe, and causes erratic beads, porosity and lack of fusion. Fixes include moving the ground, welding toward a heavy tack, switching to AC and demagnetizing the pipe.
Arc blow is pushing the root off to one side, that pipe's magnetized, wrap a few turns of lead around it.
Also heard as
- magnetic arc blow
Related terms
Ground
Shop word for the work lead and its clamp, which completes the welding circuit through the part.
DCEP
Direct current electrode positive: welding polarity with the electrode on the positive terminal.
Porosity
Gas bubbles trapped in weld metal as it freezes, showing as round holes on the surface or on film.
Lack of fusion
Weld metal that failed to fuse with the base metal or a previous pass at some boundary.