Submerged arc welding
In the plant of large diameters, the plate is cut to the specific width and beveled for the application of welding.
The Continuous Forming Mill with its Continuous Tapping System is used to form the tube. After placing the "ears" at each end of the tube, one of several automatic four-headed Submerged Arc lines applies a uniform end-to- end seam over the joint of the edges on the inside of the tube. The same process is applied from the outside.
In order to restore the ductility properties to the affected parts during welding, a heat treatment is applied at a minimum temperature of 870 ° C (1600 ° F).