28. What problems are likely to occur during the production of spiral welded pipes? How do they arise? How can they be avoided? 28.1. Causes of pore defects.

During the welding process of spiral steel pipes, if there are gas voids present in the weld surface or within the weld itself, this defect is referred to as a porosity defect. The main reason for the occurrence of porosity defects is improper cleaning of the weld surface, which can contain moisture or rust. During the welding process, influenced by the high temperature of the electric welding, these impurities such as moisture start to evaporate. As the evaporation of moisture or rust is relatively slow, voids are formed in the molten metal, and these voids constitute gas defects during the welding process. This issue is particularly pronounced during groove welding, where incomplete cleaning of the groove increases the likelihood of gas defects. The presence of gas defects severely impacts the quality of the weld, as it reduces the volume that should be welded, preventing the welding metal from fully filling the joint, leading to a decrease in weld strength and an increased risk of cracks forming in the weld.