Welded pipe processing mainly includes the following processes, each process has its own unique features and advantages:
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resistance welding (ERW)
Process characteristics: pressure is exerted on the pipe through the electrode, and at the same time, the pipe is heated to a plastic state by the resistive heat generated by the electric current through the contact surface, and then pressed and welded.
Advantage: High production efficiency, suitable for mass production. Production costs are relatively low, as a large amount of welding consumables are not required. The quality of the weld is stable and can generally meet the requirements of ordinary pressure pipelines.
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spiral submerged arc welding (SSAW)
Process characteristics: narrow steel strip is rolled into a tube and submerged arc welded while it is rolled. The weld is distributed in a spiral shape on the pipe wall.
Advantage: high adaptability of raw materials, can use narrower steel strip to produce large diameter welded pipe. High production flexibility, can produce welded pipes with different wall thickness. Reliable weld quality, suitable for high-pressure, long-distance oil and gas transmission pipelines.
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straight seam submerged arc welding (LSAW)
Process characteristics: after pre-bending the edge of the steel plate, the steel plate is rolled into a tube by forming equipment, and then submerged arc welding. The weld is distributed in a straight line on the pipe wall.
Advantages: high quality of weld seam, good protection of molten pool during welding, stable composition and properties of weld metal. High dimensional accuracy of steel pipe, good surface quality of inner and outer wall, suitable for high-pressure, high-strength requirements of the pipeline. High production efficiency, can achieve mechanised and automated production.
