difference of erw, ssaw and lsaw
It is mainly used as an oil field gathering pipe and a high-pressure natural gas pipeline in the trail for use. . .
The pipeline can be divided into seamless steel pipes through different pipeline processes (SML)
It is mainly used as an oil field gathering pipe and a high-pressure natural gas pipeline in the trail for a small number of long-distance oil and gas pipelines. Most of the long-distance pipelines use high-frequency straight-seam welded pipes (ERW)
Spiral submerged arc welding pipe (SSAW)
Submerged arc welding pipe with straight seam (LSAW)three.
Comparison of process features and quality performance of several steel pipes table below: high-frequency straight seam welded pipe (ERW )
According to the welding process, it is divided into two forms: Induction welding and resistance welding. The hot rolled wide strip coil is used as raw material. Through continuous molding, bending, welding, heat treatment, compared with spiral welded pipe, the weld is short, high dimensional accuracy, uniform wall thickness, good surface quality, high pressure, etc.
However, the disadvantage is that only wall pipes with small diameter can be produced, and welds are prone to defects such as welding resistance, unwelded penetration, trench corrosion, etc.
It is widely used in urban gas and crude oil transportation.
Spiral submerged arc welding pipe (SSAW )
When the forming angle with the center line of pipe forming, the steel coil direction (adjustable)
, Forming welding, Weld into a spiral, the advantage is that the same specification of steel bars can produce steel pipe diameter of various specifications, large range of raw materials, Weld can avoid principal stress, good stress state, the disadvantage is that the geometric size is poor, and the weld length is easy to produce defects such as cracks, pores, slag, welding, etc. compared with the straight seam length, and the welding stress is in the tensile stress state.
The general rules and regulations for the design of long-distance oil and gas pipelines for spiral submerged arc welding pipes can only be used in 3 or 4 regions.
The improved process abroad will replace the raw materials with steel plates, form welding, and then weld lean, cold expansion. After welding, the welding quality is close to UOE pipe. There is no such process in China, it is the direction of improvement of spiral pipe factory in China. \"West-
At present, the East gas \"spiral pipe is still produced by traditional technology, only the pipe holes are expanded.
The United States, Japan, Germany, in general, the negative SSAW, do not think it is appropriate to use the SSAW suitcase;
SSAW is used in parts of Canada and Italy, and SSAW is used in small quantities in Russia, and for historical reasons, most domestic mains or SSAW are used, making very strict supplementary conditions.
Submerged arc welding pipe (LSAW)
Using a single medium plate as the raw material, the steel in the mold or molding machine-voltage (roll)
Insert tube, double
Double-sided submerged arc welding and hole expansion production of Jinhang.
The finished product has a wide range of specifications, good weld toughness, good plasticity, good uniformity and tightness, large pipe diameter, wall thickness, strong pressure resistance, low temperature resistance and corrosion, and so on.
In the construction of high strength, high toughness and high quality long-distance oil and gas pipelines, the steel pipes are mostly welded by straight seam submerged arc of large diameter thick wall pipes.
According to the provisions of the API standard in large oil and gas pipelines, when the elevation, ocean and urban population-intensive areas of grades 1 and 2, the straight seam submerged arc welding pipe is the only pipe that specifies the applicable type.
According to the different molding methods, it can be divided into: UOE welded pipe, steel plate after bending at the edge, O shape after U shape, welding, mechanical cold expansion process;
JCOE welded pipe: Press \"J-E -C -
O \"Cold hole expansion welding, forming, welding process, etc;
HME welded pipe: Press \"C-C -