According to the different welding methods ,ERW steel pipe are divided into induction welding and contact welding , using hot-rolled wide steel coil as raw material, after pre-bending, continuous forming, welding, heat treatment, sizing, straightening, Cutting and other processes, compared with spiral welded pipe with short weld, high dimensional accuracy, uniform wall thickness, surface quality, high pressure, but the disadvantage is that only the production of small and medium-diameter thin-walled tube, weld prone to gray spot , Not fusion, groove-like corrosion defects. At present ,the application of a wide range of areas is the city gas, crude oil transportation.