Backing Pass
The backing weld of the joint is a weld bead applied to the root side afterward to increase joint integrity and seal thermally induced irregularities in the root area.
Physical-Chemical Mechanism of Action
The backing weld is created by adding a weld bead on the root side after back gouging or without mechanical preparation. This process seals thermally induced irregularities in the root area that may occur during welding.
Metallurgical Relevance & Risks in Welding
The backing weld increases the strength and toughness of the weld by neutralizing thermal stresses and irregularities in the root area. Without an adequate backing weld, cracks or deformation can occur, especially under high mechanical loads.
Workshop Practice & Instructions
To successfully apply the backing weld, follow these steps:
1. Back gouging: Ensure the root material is properly gouged out.
2. Apply weld bead: Add a weld bead on the root side after back gouging or without mechanical preparation.
3. Weld: Use the prescribed welding parameters to produce a homogeneous and defect-free joint.