Before welding, ensure that the raw materials of the steel pipe and welding materials such as welding rods, welding wires, and flux meet the requirements of API 5L Gr.B standards, check their quality certification documents and appearance quality, and prevent material defects from affecting the welding quality. And thoroughly remove impurities such as oil, rust, and scale on the groove and nearby surfaces of the steel pipe to reveal the metallic luster. Mechanical grinding, chemical cleaning, and other methods can be used.
For API 5L Gr.B spiral welded steel pipes, submerged arc welding has the advantages of high welding efficiency and good weld quality, and is the most commonly used welding method. During the welding process, keep the arc stable and control the angle and feed speed of the welding rod or welding wire. For spiral welded steel pipes, the welding direction is generally from the bottom of the steel pipe to the top, and it should move at a uniform speed along the spiral line. At the same time, pay attention to the shape and size of the molten pool, and adjust the welding parameters in time to keep the molten pool in good fluidity and stability.
After welding is completed, remove slag, spatter and other impurities on the weld surface in time. Mechanical grinding, wire brush cleaning and other methods can be used to make the weld surface smooth and tidy, which is convenient for subsequent quality inspection and anti-corrosion treatment.
According to the requirements of relevant standards and specifications, non-destructive testing is carried out on the weld, such as radiographic testing (RT), ultrasonic testing (UT), magnetic particle testing (MT), etc., to detect whether there are defects such as pores, slag inclusions, cracks, etc. inside the weld. Non-destructive testing should be carried out after the weld has cooled to room temperature, and the detection ratio and qualified standards should comply with the provisions of standards such as API 5L.
API 5L Gr.B Spiral Welded Steel Pipe
