What is the effect of excessive voltage in MIG welding?

Excessive voltage in MIG welding leads to a phenomenon known as burn-through, primarily because it produces a very broad arc with increased heat input. This intense heat can cause the base metal to melt at a faster rate than intended, especially if the material being welded is thinner. As the voltage rises, the arc becomes more erratic and unstable, which can result in excessive melting of the edges of the workpiece. This uncontrolled melt-through can damage the workpiece, creating holes, or "burn-through," effectively compromising the integrity of the weld.

In contrast to aspects like increased penetration or creating a flatter bead, which may have some correlation with higher voltage settings, burn-through is a direct consequence of excessive heat resulting from high voltage. Additionally, higher voltage may lead to increased spatter, which contradicts the notion of reduced spatter as a benefit. Therefore, recognizing the effect of excessive voltage in creating burn-through is essential in ensuring quality results in MIG welding projects.