How does travel speed affect the quality of a MIG weld?

A higher travel speed can lead to undercutting and poor penetration because it reduces the time the arc has to melt the base metal and filler material effectively. In MIG welding, the travel speed directly influences the amount of heat applied to the workpiece. When the travel speed increases, the weld bead does not have enough time to fuse properly, which can lead to inadequate penetration into the base metal. This situation may cause the edges of the weld to become pronounced, leading to undercutting where the base material is eroded away, creating a groove adjacent to the weld bead. Proper travel speed is crucial; it needs to be balanced to ensure that the molten pool of metal solidifies correctly, providing a strong and aesthetically pleasing weld without defects.