Welded steel pipe is bent round, square shape with a steel or steel plate and then welded into the other, the surface of the pipe joints. Welded steel pipe is used in blank or strip.

According to weld shape, welded steel pipe can be divided into straight welded pipe and spiral welded pipe. Among them, the straight welded pipe: the production process is simple, high efficiency, low cost, rapid development. Spiral welded pipe: Longitudinal strength is generally higher than that, can narrow the billet production of large diameter pipe, you can also use the same width of the billet production of different pipe diameters. However, with the same length of straight pipe seam, compared weld length of 30 to 100%, and lower production rate. Therefore, most of the use of smaller diameter straight seam welding pipe, large diameter spiral welded pipe are mostly used.

By the application, welded steel pipe can be divided into general-use pipe, galvanized pipe, oxygen pipe, wire pipe, metric pipe, roller pipe, deep well pump tube, automotive tube, transformer tube, welding thin-walled tube , welding shaped tube and spiral welded pipe.

Pipe material and its use of several different varieties divided into the following: GB/T3091-1993 (low-pressure fluid Galvanized welded steel pipes). Mainly used for conveying water, gas, air, oil and hot water or steam heating and other general low pressure fluid control and other purposes. The representative material Q235A grade steel.

GB/T3092-1993 (low-pressure fluid Galvanized welded steel pipes). Mainly used for conveying water, gas, air, oil and heating hot water or low pressure steam and other fluids, and other general purpose control. The representative material as: Q235A grade steel.
GB/T14291-1992 (mining fluid welded steel pipe). Mainly used for mine air pressure, drainage, gas discharge axis with straight seam welded steel pipe. The representative material Q235A, B grade steel.

GB/T14980-1994 (large diameter low pressure liquid delivery welded steel pipe). Mainly used for conveying water, sewage, gas, air, low pressure steam heating fluid, and other uses. The representative material Q235A grade steel.

GB/T12770-1991 (mechanical structure with stainless steel welded pipe). Mainly used for machinery, automobiles, bicycles, furniture, decorative hotels and restaurants and other mechanical components and structural parts. The representative material 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb and so on. GB/T12771-1991 (fluid transport stainless steel welded pipe). Mainly used for conveying low pressure corrosive media. Representative material for the 0Cr13, 0Cr19Ni9, 00Cr19Ni11, 00Cr17, 0Cr18Ni11Nb, 0017Cr17Ni14Mo2 and so on.

ERW

ERW is used for transporting oil, gas and other vapour-liquid objects and can meet the requirements of high and low pressure besides, widely used in aviation, aerospace, energy, electronics, automobiles, light industry as well as various industry departments So far It occupy a decisive position in the field of transporting tube all over the world.

SSAW

Sprial welded steel pipe(SSAW) is mainly used in oil and gas transmission pipeline, and its specification is expressed as outside diameter * wall thickness .according to the external structure, it is classified single welding and double welding. Technically the welded steel pipe should ensure that hydrostatic test, weld tensile strength and the cold bending property can comply with the regulations.

LSAW

LSAW has large diameter and wall thickness, resistance to high pressure, resistance to low temperature and strong corrosion characteristics. When constructing high strength and toughness, high quality oil and gas pipeline over long distances, what is required is mostly large caliber straight double submerged arc welding joints. According to the API standard provisions LSAW is the only designated for tube type when passing through the cold region, submarine, the urban population dense area of 2 kinds, 1 region in the large oil and gas pipeline.