Welded pipe production methods are mainly straight seam welded pipe and spiral welded pipe. At present, there are about 1600-1800 straight ERW welded joints, 5 sets of straight seam large diameter submerged arc welded pipe units and 90 sets of spiral welded pipe units with an annual production capacity of 9 million tons or more.
Welded pipe production in both non-ferrous and black production have a faster development. Small and medium straight seam welded pipe are basically produced by roll continuous molding machine, the unit has the advantages of simple equipment, less investment, high output, low cost, good mechanical property, high precision, uniform wall thickness, smooth surface and good weld quality features. High-frequency welded pipe machine currently produces φ5 ~ 660 × 0.5 ~ 15mm water gas pipelines, boiler tubes, tubing, oil drilling pipe and machinery industry tubes. When using roll forming method, the product specifications can be expanded to φ400 ~ 1220 × 6.4 ~ 22.2mm.
UOE method is the main method of producing large diameter straight seam welded pipe, which can produce φ406 ~ 1625 × 6.0 ~ 32mm, up to 18m pipe. The United States first applied this method to production in 1951. With the development of the oil and gas industry, the demand for large-caliber high-strength pipe increased sharply, which promoted the development of the production law. The world's ownership is more than 30 sets. In recent years, rapid development, the new 4 sets of UOE.
Spiral welded pipe appeared in 1888. Currently the United States, West Germany has produced a diameter of 3m above the thickness of 25.4 mm spiral welded pipe. Compared with UOE, spiral welding can use the same wide coil production of different diameter pipe; inside and outside the weld is spiral, with the role of enhancing the rigidity of the pipe; tube straightness, without setting the straightening machine, the outer diameter Ovality is small, but the outside diameter deviation is greater than the UOE method; the production process is easy to mechanization, automation and continuity; equipment appearance is small, less investment.
