ERW and LSAW are both the straight seam welded pipes.
ERW or Electric Resistance Welded Pipes
The straight seam high frequency welded pipe (ERW) is formed by heating the edge of the tube billet with the skin effect and proximity effect of high frequency current after the hot rolled coil is shaped by the forming machine, and then pressure welding is carried out under the action of the extrusion roller.
ERW pipes manufacturing process
The first step in the manufacturing process is the preparation of the raw material, which is usually a steel coil. The coil is flattened and trimmed to the desired size, and the edges are prepared for welding. The next step is to feed the coil through a series of rollers that gradually bend the steel into a round shape.
After this, the edges of the steel are welded together using an electric current. The electric current generates heat, which melts the edges of the steel, allowing them to fuse together. The welded area is then cooled using a water cooling system.
Once the welding is complete, the pipe is passed through a sizing machine that further shapes and straightens the pipe. The machine also checks the thickness and diameter of the pipe to ensure it meets the required specifications.
Finally, the pipe is cut to the desired length and undergoes various tests to ensure its quality. These tests include ultrasonic testing, X-ray testing, and hydrostatic testing, among others.
LSAW or Longitudinal Submerged Arc Welded Pipes
LSAW pipe is made of steel plate through different forming processes, such as double-sided submerged arc welding and expanding after welding. The forming methods of LSAW pipe include UOE, RBE, JCO, etc.
Advantages of JCO molding method
JCO forming is progressive pressure forming, which changes the forming process of steel pipe from two steps of UO forming to multi steps. In the forming process, the steel plate has uniform deformation, small residual stress and no scratch on the surface. The processed steel pipe has great flexibility in the size range of diameter and wall thickness. JCO molding method can meet more requirements of users for steel pipe specifications.
