What is the first pass in a bevel pipe weld called?

The first pass in a bevel pipe weld is known as the root pass. This step is crucial in the welding process because it establishes the initial joint between the two pieces of pipe being welded. The root pass is typically designed to create a strong and consistent foundational weld that will support subsequent passes. It is essential for ensuring proper penetration and fusion at the joint, which are critical for both strength and durability.

This stage of the welding process involves the welder carefully controlling the heat and travel speed to ensure that the molten weld metal penetrates deeply into the bevel of the workpieces. The quality of the root pass can significantly influence the overall integrity of the completed weld. Subsequent passes, often referred to as fill and cap passes, build upon the root pass, but the root pass is unique because it is the first point of contact where the two pipe pieces are fused together.