When making a T-weld, what should the direction of the arc be to avoid undercutting?

In the context of making a T-weld, directing the arc toward the bottom plate is crucial to achieving a strong weld while avoiding the problem of undercutting. When the arc is aimed at the base material, it allows for better penetration into the joint and encourages proper fusion with the base materials on both sides of the weld. This technique helps generate adequate heat, which is essential to melt the filler material efficiently and prevent the formation of a groove along the edge, known as undercut.

Undercutting occurs when the heat input is insufficient or misdirected, leading to a weakened area along the edge of the weld. By directing the arc toward the bottom plate, the welder can help ensure that the filler metal properly flows into the joint rather than retreating away from the base metal, which can be a common mistake when the arc is directed away or at an incorrect angle.

Understanding the dynamics of heat distribution and flow in weld joints is key to achieving good welding results, making the correct arc direction a critical factor in the successful execution of T-welds.