Spiral submerged arc welded pipe (SSAW) is a steel coil when the forward direction and the forming tube centerline forming angle (adjustable), while forming edge welding, the weld into a spiral, the advantage is the same specifications of the strip can be produced A variety of diameter specifications of the pipe, a larger range of raw materials to adapt to the weld to avoid the main stress, the force better, the disadvantage is the geometric size is poor, compared to the length of the seam straight seam, easy to crack, Slag, welding and other welding defects, welding stress was tensile stress state.
General oil and gas pipeline design specifications for long-distance spiral submerged arc welded pipe can only be used for 3 categories, 4 areas. Foreign this process will be improved after the raw material to steel plate, so that forming and welding separately, the pre-welding and lean, cold after welding diameter expansion, the welding quality close to the UOE tube, there is no such technology, is China's spiral Plant to improve the direction. "West-East Gas Pipeline" is still used by the traditional spiral pipe production process, but the pipe end was expanded diameter. SSAW has been used in Canada and Italy, SSAW has been used in Russia and SSAW has been used in a small amount. Moreover, very strict supplementary conditions have been made. For historical reasons, the majority of domestic trunk lines still use SSAW .