What causes arc blow during the welding processes?

Arc blow occurs when the arc produced during welding is deflected from its intended path, and one of the key causes of this phenomenon is the influence of magnetic forces. When welding, especially with direct current (DC), the welding arc can be affected by existing magnetic fields. These fields can arise from the electrical equipment being used or from other equipment in the vicinity, causing the arc to wander or have an erratic behavior. This is particularly noticeable in processes like Shielded Metal Arc Welding (SMAW) when the electrode is DC positive, resulting in the arc being attracted to magnetic poles and thus impacting the quality of the weld.

Addressing other factors: while heat variation can affect the physical properties of the weld, it does not specifically cause arc blow. An electrical short circuit can lead to severe operational issues, but it does not correlate directly with the arc's deflection behavior. Lastly, using the wrong electrode type might cause other welding problems such as poor fusion or contamination, but it doesn't inherently lead to the deflection of the arc caused by magnetic influences.