Welding quality control measures of LSAW steel pipe

　　Large diameter LSAW steel pipe with its big wall thickness, good material, stable processing technology, becomes the preferred pipe by largest domestic and foreign oil and gas transportation project. In the large diameter LSAW steel pipe welded joints, weld and heat affected zone are the most prone to produce a variety of defects, and welding undercut, pores, slag, not fused, not penetration, welding cracks are the main form of welding defects, and also are the origins those often make LSAW steel pipe produce quality accident. The quality control measures will be listed below, if you you are interested in the production process of LSAW steel pipe, you can click the hyper-link.

　　1.The quality control before welding:

　　1) First of all, pipe manufacturer should take control of the quality of raw materials, after passing the inspection, raw materials can formally enter the construction site. And pipe manufacturer resolutely put an end to the use of substandard steel.

　　2) The next is the management of the welding material. Checking whether the welding material is a qualified product, whether storage and baking system is implemented, whether the surface of the welding material is clean and no rust, and whether the electrode coating is intact, with mildew or not.

　　3) The next is the welding area cleaning management. Check the cleaning quality of the welding area, there shall not be water, oil, rust and oxide film and other dirt, which plays an important role to prevent the occurrence of external defects in the weld.

　　4) Finally, choosing the appropriate welding method, it should be implemented before the test welding, after welding principle.

　　2. The quality control during welding:

　　1) According to the welding process to review the specifications of the wire and flux is correct or isn't, to prevent the wrong welding wire and flux caused by welding quality accidents.

　　2) Monitor the welding environment, when the welding environment is not good (temperature below 0 ℃, relative humidity greater than 90%) pipe manufacturer should take appropriate measures after welding.

　　3) Checkout the groove size, including the gap, blunt edge, angle and wrong, etc. meet the process requirements or not before pre-welding.

　　4) Checkout the selected welding current, welding voltage, welding speed and other process parameters are correct or aren't in the submerged arc internal and external welding process.

　　5) Supervise the welding personnel in the submerged arc internal and external welding full use of the length of the pipe end of the arc plate to strengthen the internal and external welding arc plate use efficiency, which helps to improve the quality of pipe end welding.

　　6) Supervise the welding staff in the welding is the first clean up the slag, whether it has been completely handle joints, groove whether there is oil, rust, slag, water, paint and other dirt.