Pre-welding process of LSAW steel pipe

　　The pre-welding technology of LSAW steel pipe consists of three technical supports: pre-welding process, pre-welding equipment and common problem treatment.

　　In the pipeline construction, the long-distance oil and gas pipeline is developing towards large-diameter, high-pressure transportation and thick-walled subsea pipeline. More and more pipelines require the use of LSAW steel pipes. With the introduction and production of LSAW steel pipe production line, it is particularly important to master advanced LSAW welding technology.

　　1. Pre-welding process of LSAW steel pipe

　　During pre-welding, the steel pipe blank shall be welded first, and then the continuous gas shielded welding shall be carried out. At the same time, the weld state and welding quality shall be monitored and fed back. The specific process is as follows: the inlet roller table receives the tube blank → adjusts the opening position of the tube blank → the conveying device delivers the tube blank → the tube blank closes → confirms the joint quality → the welding gun drops to prepare for welding → starts the laser tracker to track → opens the protective gas and cooling water valve → starts the welding (the tube blank is fed at the welding speed) → stops the welding at the end of the arc extinguishing → lags off the protective gas → the welding gun rises and returns → the tube blank is transferred to the next process. At this point, a pre-welding cycle is completed.

　　In the above process, adjusting the opening position of the tube blank means adjusting the opening seam position to the required position, which can be done through the camera monitoring system in the electronic control system.

　　To confirm the quality of the joint is to confirm the misalignment of the joint and the gap of the joint. Only after confirmation can the joint be tracked and welded.