What type of welding technique should be avoided when making the first weld pass on equipment in service?

The weaving technique involves making passes that move back and forth across the weld joint, which can lead to several potential issues when making the first weld pass on equipment that is already in service. One of the primary concerns is heat input. Weaving introduces variable heat zones and can cause excessive heat that may affect the integrity of the base material or any surrounding structures. This can lead to distortion, changes in microstructure, and the possibility of introducing stresses that may not exist with a more controlled technique.

In addition, weaving may not provide adequate penetration or fusion at the root of the weld joint when compared to a more linear approach such as stringer beads. This can result in incomplete weld profiles which are critical for maintaining the strength and reliability of the joint, especially in service environments where the weld is subject to stress and fatigue.

Using stringer beads, in contrast, typically creates a more focused arc and minimizes the heat-affected zone, enhancing penetration and fusion, and making it a more suitable choice for first passes. Techniques that limit excessive heat and promote stronger welds are essential for ensuring longevity and structural integrity, especially in service applications.