A drag angle greater than what degree is likely to reduce penetration and may cause overlap?

A drag angle greater than 30 degrees can indeed hinder penetration and potentially lead to overlap in MIG welding. The drag angle refers to the angle formed between the welding gun and the workpiece relative to the direction of travel. When the drag angle is too steep, it can prevent the welding arc from adequately penetrating the base material.

This is because a larger drag angle tends to push the arc away from the weld pool and increases the heat input to the weld's surface rather than allowing it to focus on the underlying material. Consequently, the heat does not effectively melt the base metal, resulting in a shallow weld bead that may have insufficient penetration. Moreover, if the angle is steep enough, it can lead to molten weld metal rolling off the surface rather than being deposited into the joint, which causes overlap.

Maintaining a proper drag angle, typically closer to 15 to 30 degrees, helps in ensuring that the arc remains directed effectively towards the joint, facilitating good penetration and minimizing the risk of defects such as overlap.