The aim of the present investigation was to demonstrate the fundamental suitability of hybrid welding for pipeline construction. Various process arrangements, arc types and weld preparations were investigated in this case. In the given circumstances, the neutral pulsed arc process with a preceeding laser beam process and a modified Y-weld preparation with a residual root face of 6 mm constitutes the current optimum for a laser power of 4.5 kW. A 10-kW laser system was used for a root face thickness of 8 mm at a power of 6.5 kW. By integrating a second arc process, it was possible, for a pipe wall thickness of 10 mm, not only to produce closed weld profiles but also to reduce the increase in the hardness of the heat-affected zones in the root region. The examination of the orbiting technique with regard to the rougher utilisation climate revealed the following shortcomings: The attainable welding speeds were too low. The sensor equipment did not supply the required accuracy. Deliberations must therefore be made about other sensor concepts. Position-dependent adjustment of the laser power is necessary. The conversion to the directional or orientational changing is very time-consuming and constitutes a source of errors because of the many setting steps. In this respect, the aims of the design-related refinement are to further increase the stability of the orbiting movement around the pipe and to adapt it to the conditions of the hybrid process. Here, attention is concentrating on raising the drive power in order to be able to achieve welding speeds up to 3 m/min. Current investigations relates to the process optimisation using a 12 kW fibre laser system show the potential of the hybrid process at high laser output with brilliant beam qualities. In the next step, these investigations are to be supported by statements about the tolerance sensitivity.
Laser-GMA hybrid welding - Applications in pipeline construction
Welding and Cutting ; 8 , 4 ; 214-221
2009
8 Seiten, 18 Bilder, 5 Tabellen
Aufsatz (Zeitschrift)
Englisch
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