Orbital laser welding: automated welding and weld testing in a single step
In many years' cooperation with Mannesmann Line Pipe, Schweißtechnische Lehr- und Versuchsanstalt (SLV) Halle has developed a welding process for faster and more economical pipeline stringing: the orbital laser welding process. The idea behind it: to have laser beam welding and weld inspection performed by a device that rotates around the pipe, thus completing a pipe joint in a single operating step.
A first field test in conjunction with a pipeline revamp near Greifswald in north-eastern Germany has fully met the high expectations regarding this technology. In just 70 seconds, two DN 300 pipes were joined by a perfect girth weld. The energy input in welding is very concentrated, but the high thermal conductivity of steel ensures fast cooling to temperatures of 60 to 90 °C. Accordingly, the weld can be tested immediately after its completion. Since field coating of the weld area presupposes its prior testing, the logistically complex process sequence of welding, testing and field coating, which often extends over several days, can be shortened to a single operating step.
The inspectors from TÜV Süd confirm that the welding process has proven itself in the pilot test near Greifswald. The welds passed the relevant tests with flying colors. Given these encouraging results, the researchers are now focusing on coupling the weld test to the welding process and integrating it into the welding device.