What is the main cause of arc blow in welding?

Arc blow in welding primarily occurs due to the influence of magnetic fields. When welding, especially in processes involving direct current (DC), the electric arc can be disrupted by magnetic fields. These fields may arise from nearby electrical equipment or the Earth’s magnetic field. When an arc is deflected by these magnetic fields, it can cause instability in the welding process, leading to issues such as inconsistent penetration, weld defects, or difficulty maintaining the arc.

While other factors, such as material type, improper settings, and excessive heat, can influence the overall quality of a weld, they do not specifically cause arc blow. The primary mechanism behind arc blow is the interaction of magnetic fields with the welding arc, which is why it is considered the main cause in this context. Understanding this concept is key for addressing challenges in welding and ensuring high-quality results.