(2) Welding: The longitudinal joints are welded (submerged arc
welding, SAW) through double V type butt welds, obtaining
the corresponding rings. Then, the rings are joined performing
circumferential welds (also using SAW techniques and double
V type butt welds). As a result, primary cylinder/cone trunk
shaped stretches of different lengths are obtained. The number
of rings joined depends on the length of the stretches
(generally varying from 10 to 30 m in the case of wind towers).
Fig. 2 shows a scheme of a double V type butt weld, before
and after the welding process. No defects were found on the
longitudinal welds, so the analysis performed here is only
referred to the circumferential ones.
(3) Surface treatments (i.e., shoot peening, painting . . . ), drying and
assembly of the auxiliary equipment (flanges, ladders . . . ).
(4) Transport from the centre of production to the final location
(i.e., wind farm).