double-sided submerged arc welded pipeIt is a welded steel pipe made of steel plate or steel strip after crimping. It has the advantages of small size deviation, uniform wall thickness, simple production process, high production efficiency, many varieties and specifications, and less equipment investment. However, because the welding performance of welded steel pipes is lower than that of seamless steel pipes, the utilization rate in petrochemical plants is very low. Double-sided submerged arc welded pipe is divided into straight seam and spiral seam according to the weld form.

With the development of modern industrial technology and the progress of welding inspection technology, the weld quality of welded steel pipe is continuously improved, and the varieties and specifications are increasing day by day, so it is widely used in petrochemical plants.

Welding speed is one of the main parameters of welding process, which is related to heating system, weld deformation speed and mutual crystallization speed. The purpose of the weld induction heating annealing treatment is to eliminate the welding stress and make the mechanical properties of the weld, the heat affected zone and the base metal consistent. This heat treatment process is widely used in the production of welded pipes, and the purpose of heating and tempering treatment is to improve the overall mechanical properties of welded pipes. This heat treatment process is rarely used.

The manufacturing process of double-sided submerged arc welded pipe is a new type of welded steel pipe forming technology that emerged in the 1990 s. The main forming process of this technology is to mill (or plow) the edge of the pre-welded counterpart of the steel plate first, then pre-bend in the width direction of the steel plate, and then gradually form in the order of J→C→O, in the process of forming, three-point bending die is used as the basic principle for each stamping after several times of pressure stamping. Welding quality with the acceleration of welding speed and progress. This is because the shortening of the heating time narrows the width of the edge heating zone and shortens the time for forming metal oxides. If the welding speed is reduced, not only the heating zone becomes wider, but also the width of the melting zone changes with the change of the input heat, forming a larger burr. In low-speed welding, less heat input makes welding difficult, and defects are easy to occur if the specified value is not met.

　　double-sided submerged arc welded pipeMore for construction.

The application of large-diameter, thick-walled, high-grade double-sided submerged arc welded pipes in the field of steel structures has absorbed the advanced design concepts of foreign steel pipe building structures and port offshore equipment, and attaches importance to steel pipes for power generation as structural parts. The mature application in the field of port offshore equipment outside the construction field has quickly been recognized by the international industry and peers, and has achieved fruitful results. The pipeline is a high-strength steel prefabricated by the factory and then brought to the construction site for welding in the field. The welding process manufactured by the factory is submerged arc welding. Now, submerged arc welding has developed into double wire submerged arc welding and multi wire submerged arc welding, and the efficiency is further improved.