Arc blow can cause a number of welding problems, including excessive spatter, incomplete fusion, porosity and lower quality.
Magnetic arc blow is caused by an unbalanced condition in the magnetic field surrounding the arc.
This unbalanced condition results from the fact that at most times, the arc will be farther from one end of the joint than another and will be at varying distances from the workpiece connection.
Imbalance also exists because of the change in direction of the current as it flows from the electrode, through the arc, and into and through the workpiece.
What is it and how can it be prevented?
Learn more: how to prevent arc below?.