Single and double-sided welding process of stainless steel pipe

When welding stainless steel pipelines, the weld must be completely penetrated to ensure that the quality and performance of the pressure components meet corresponding requirements. Butt welds of stainless steel pipes generally use double-sided welding or single-sided welding and double-sided forming to ensure penetration of the back side of the weld.

The double-sided welding process is often used. Although there are certain requirements for the operating skills of the processing personnel, they are not very strict. However, due to restrictions on the size and shape of components, for example, small-diameter containers and pipes cannot be welded inside, and can only be welded on the outside of the container. Generally, single-sided welding can easily lead to the inner surface of the stainless steel pipe not being penetrated or having welding defects such as welding nodules and undercuts, which cannot meet the welding quality requirements. Therefore, there is a welding operation process of single-sided welding and double-sided forming.

The single-sided welding and double-sided forming operation process is a welding technology that requires relatively high skills. It requires welding on the front of the groove without any auxiliary measures on the back of the groove of the weldment, and the groove must be ensured to be straight and straight after welding. There is a certain amount of weld reinforcement on both sides to obtain a uniform, neat and well-formed welded joint. It is a relatively difficult welding process in electrode arc welding. It is mainly suitable for important components that cannot remove the welding root from the back and cannot be welded from the inside. The joint forms suitable for single-sided welding and double-sided forming of arc welding, mainly include butt welds of plate butt joints, tubular butt joints and riding tube-sheet joints.

Depending on the location of the welding joint, flat welding, vertical welding, horizontal welding and overhead welding can be selected for welding.

This kind of single-sided welding and double-sided forming welding operation method is usually suitable for butt welds with grooves and small blunt edges. Using electrode arc welding to achieve single-sided welding and double-sided formed welds, the goal can be achieved through intermittent arc extinguishing welding or continuous arc welding processes.

The intermittent arc extinguishing welding process can use short-term repeated ignition and extinguishing of the arc during the welding process to control the formation of the weld. That is, when the arc burns, it heats and penetrates the root of the groove to achieve a molten pool with excellent fusion; when the arc is extinguished, Crystallize the molten pool to achieve a double-sided weld. The continuous arc welding process is that the arc burns continuously during the entire welding process without extinguishing the arc. Its operation methods are divided into arc raising method and stable arc welding method.

The arc stabilization method can also use a current regulator to adjust the current to a slightly larger value when igniting the arc to facilitate penetration of the arc ignition section. After the arc is ignited, adjust it to normal and switch to normal welding. At the end, adjust the welding current again. Low, some arc welding rectifiers have added some functions. The arc raising method means that the welding rod swings on both sides of the groove. When the molten pool is generated, the arc leaves the molten pool and reaches the edge of the groove. When the molten pool solidifies, the arc stopped at the edge of the groove quickly moves to the molten pool area, and then Re-welding process.