Arc blow can also cause porosity in the weld, as can joint contamination, high welding speed, and a long welding arc, especially when low-hydrogen electrodes are used.
2.
It can be caused by excessively high current, a long arc, or arc blow, a condition associated with direct current characterized by the electric arc being deflected away from the weld pool by magnetic forces.
3.
Arc blow tends to occur if the material being welded has residual magnetism at a certain level, particularly when the weld root is being made, and the welding current is direct current ( DC positive or negative ).
4.
Magnetic arc blow is popularly attributed to a change in the direction of gauss and becomes severe at densities of, equal to or greater than, 40 gauss; it is directional and can be classified as " forward " or " backward " moving along the joint, but can occasionally occur to the sides depending on the orientation of the poles to the workpiece.
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