What is "arc blow" in welding?

Arc blow refers specifically to the deflection of the welding arc that occurs due to the influence of magnetic fields. This phenomenon is especially common in processes like MIG and TIG welding, where the arc can be disturbed by external magnetic forces, such as those generated by nearby equipment or the welding current flowing through the base metal.

When the welding arc is deflected, it can lead to inconsistencies in the weld bead, uneven penetration, or other quality issues, making it an important consideration for welders to understand and manage. Techniques to mitigate arc blow often involve repositioning the workpiece, adjusting the grounding techniques, or altering the welding parameters to minimize magnetic interference.

Understanding arc blow is crucial for achieving a high-quality weld, as managing this effect can directly impact the weld quality and structural integrity of the finished product.