Spiral steel pipe for petroleum transportation specializes in manufacturing national standard spiral welded steel pipe, which is formed by bending steel strip or steel plate into circular or square shape and then welded with seams on the surface. According to different welding methods, it can be divided into arc welded pipe, high frequency or low frequency resistance welded pipe, gas welded pipe, furnace welded pipe, Bondi pipe and so on. According to weld shape, it can be divided into longitudinal welded pipe and spiral welded pipe. Electric welded steel pipes are used for petroleum drilling and mechanical manufacturing. Furnace welded pipe can be used as water gas pipe, large diameter straight seam welded pipe for high pressure oil and gas transmission, spiral welded pipe for oil and gas transmission, pipe pile, pier and so on. Welded steel pipe has lower cost and higher production efficiency than seamless steel pipe. A large spiral steel pipe refers to a spiral steel pipe with a diameter of more than DN850. The main raw material for production is strip steel. The strength of spiral pipe is generally higher than that of straight seam welded pipe. It can produce welded pipe with bigger diameter with narrower blank, and welded pipe with different diameter can also be produced with blank of the same width. Large spiral steel pipe adopts double-sided submerged arc welding technology. Submerged arc welding has the advantages of stable welding quality, high welding productivity, no arc and little smoke and dust. The main parameters are outer diameter, wall thickness, length and so on.