Quality control method of LSAW steel pipe

　　Large diameter LSAW steel pipe with its large wall thickness, good material, processing technology and stability, has become the first choice of steel large oil and gas transmission project at present at home and abroad. LSAW steel pipe in large diameter welded joints, the weld and heat affected zone is the most easy to produce all kinds of defects, and welding undercut, porosity, slag inclusion, incomplete fusion, lack of penetration, overip, burn, welding crack is the main form of welding defects, it is often the origin of the LSAW steel pipe the quality accident.

　　Quality control measures:

　　1. 1) before the welding quality control to quality first good raw materials, can be officially entered the construction site after passing inspection, and resolutely put an end to the use of substandard steel.

　　2) followed by the management of welding materials. Check whether the welding materials for qualified products, storage and baking system is executed, issued by the welding material surface is clean without rust, the electrode is intact, there is no mildew.

　　3) again is the welding area clean management. Check the welding area clean quality, no water, oil, rust and other dirt film, which plays an important role in avoiding weld external defects.

　　4) select the appropriate welding methods, welding principle should be applied, after the implementation of welding test.

　　2. 1) quality control in welding according to welding procedure review of welding wire and flux specifications are correct, to prevent misuse of wire and flux caused by welding quality accident.

　　2) to supervise the welding environment, welding environment is not good (when the temperature is below 0 DEG C, the relative humidity is greater than 90%) to take corresponding measures after welding at.

　　3) to test the pre groove size before welding, including clearance, edge, angle and the wrong port meets the technical requirements.

　　4) used in the welding process and automatic submerged arc welding current, welding voltage, welding speed and other parameters are correct.

　　5) supervision personnel in the submerged arc welding automatic welding and make full use of the pipe end arc plate length, and enhance the efficiency of the use of welding arc plate, which helps to improve the welding quality of tube end.

　　6) personnel in the supervision of welding repair welding is clean, whether the first slag has been completely processing joint, whether there is oil, rust, slag, water, paint and dirt groove.