Steel pipe is a kind of steel, which open on both ends and has a hollow section, the ratio of length and the surrounding is larger. We can classify steel pipe into seamless steel pipe and welded steel pipe by production methods. The specification of steel pipe can denoted by overall dimensions (such as the diameter or length) and the wall thickness. Its size range is very wide, such as capillary with small diameter, and large diameter pipe with larger diameter. Steel pipe can be used in the pipeline, thermal technology equipment, industrial machinery, petroleum geological exploration, containers, chemical industry and special purpose.Steel pipe can be divided into seamless steel pipe and welded steel pipe (tube). According to the cross section shape and can be divided into circular tube and special-shaped tube, steel tube is widely used, but there are some square, rectangle, semicircle, hexagonal, equilateral triangle, octagonal special-shaped steel tube. For fluid under pressure steel pipe are hydraulic experiment was carried out to test the compression ability and the quality, under the pressure of regulation does not leak, soaked or expansion of qualified, some steel pipe according to the standard or the buyer requires edge test, flaring test, flattening test, etc.
Pipe couplings are the devices used to connect two or more pipes together. The sprinkler coupling usually adopt the same or similar material as the pipe. The pipe couplings always have two type: the rigid or flexible. The internal diameter of the sprinkler coupling that made by the coupling manufacturer can be changed to adjust to pipes with different sizes. The pipe couplings can also be equipped with extra features such as inspection openings, flow meters, or valves.