LSAW,SSAW and ERW
Straight seam high frequency (ERW) by welding and induction welding is divided into different forms of contact of two welding, hot-rolled wide coil as raw material, through pre-bending, continuous forming, welding, heat treatment, sizing, straightening, cutting, etc. step short compared to the spiral weld, high dimensional accuracy, uniform thickness, surface quality, under pressure advantages, but the disadvantage is that only the production of small diameter thin-walled tube, easy to produce gray leaf spot weld, incomplete fusion ditch-like corrosion defects. Currently wider field of application of city gas, crude oil and other oil products transportation. Spiral submerged arc ( SSAW ) pipe volume is the forward direction of its centerline forming tube forming angle (adjustable) while forming side welding, weld into a helix, the advantage of the same specifications can produce a variety of diameters steel, adapt to a wider range of raw materials, the main...