Spiral steel pipes(SSAW steel pipe) are widely used welded steel tubes, which are widely used in petroleum, chemical, electric power, natural gas, refrigeration and other pipeline engineering, steel structure and other industries.
What are the requirements for spiral welded pipe welding?
1) If the weld seam gap is too small, the proximity effect will increase and the welding heat will be too large, causing the weld seam to burn or the weld seam to form deep pits after extrusion and rolling, which will affect the surface quality of the weld seam.
2) If the weld seam gap is too large, the proximity effect will be reduced, the eddy current heat will be insufficient, and the intergranular joint of the weld seam will be poor, resulting in infusion or cracking.
After the two edges of the tube blank are heated to the welding temperature, under the extrusion of the extrusion roller, the common metal grains are formed to penetrate and crystallize each other, and finally form a firm weld. If the extrusion force of the spiral welded pipe is too small, the number of common crystals formed will be small, the strength of the weld metal will decrease, and cracks will occur after being stressed; if the extrusion force is too large, the molten metal will be squeezed out of the weld, It not only reduces the strength of the weld, but also produces a large number of internal and external burrs, and even causes weld defects.
Problems to be paid attention to when welding spiral welded pipes
1) The traces of welding are continuously reduced, so that it is difficult to see where there is welding. This requires the use of advanced welding equipment to complete, and the traces can be continuously reduced, so that the welding process can be greatly improved.
2) The edge welding should be fine, the flatness should be high, and the process should be reliable, especially in every detail of the spiral welded pipe, there should be no burrs. Therefore, it can be seen that the technical level will be higher in the actual welding. In short, after strictly grasping the welding requirements, it is very simple to improve its process standards.
3) Establish a complete welding process and complete the welding according to the requirements. In this way, the spiral welded pipe can have a substantial improvement in the overall quality, and the quality advantages brought will become more and more significant. Therefore, in order to become more and more popular in the market, the key points of welding must be grasped scientifically and reasonably.