DN800 SSAW Pipes

Submerged arc welding technology, how to create an "impeccable" weld?

Weld is the weak link of pipeline, and LSAW pipe adopts double-sided submerged arc welding technology, which eliminates the hidden danger of weld from the process. When welding, the flux layer completely isolates the arc from the air, which avoids the oxidation of the molten pool. At the same time, the slag formed after flux melting can protect the weld formation and reduce defects such as porosity and slag inclusion. The design of the inner and outer double weld makes the thickness of the weld thicker than that of the pipe wall, forming a "double guarantee".

During the welding process, the computer control system will adjust and control the current, voltage and welding speed in real time to ensure that the amount of deposited metal per millimeter of weld is accurate and consistent. For example, the LSAW pipe produced by Huayou Steel Pipe, using laser-arc hybrid welding technology, the grain size of the weld reaches ASTM 10 level, and the hydrogen permeability is only 38% of that of the traditional process. After welding is completed, the weld seam needs to be checked by X-ray inspection and ultrasonic flaw detection, and the defect detection rate reaches 100%.