STABILIZATION OF PULSED GMAW IN TITANIUM WELDS WITH LOW-POWER LASERS

摘要

Fabricated titanium structures are of great interest foraircraft and military applications. However, in thepulsed gas metal arc welding (GMAW-P) of Ti it isdifficult to achieve an acceptable weld due to thewandering around of the molten pool by cathode spot.The results of the "wandering" is an unstable metaltransfer, spatter generation, and irregular weld beadshape. These results are more common in thinner Timaterials (<1 mm). As an alternative to GMAW-P,gas tungsten arc welding (GTAW) is most often used.However, GTAW in thinner materials is done at muchslower speeds and therefore higher heat inputs.Because of the higher heat input the parts are morelikely to be distorted.An alternative to GMAW-P or GTAW of Ti alloys isthe use of lasers. Autogenous laser and hybrid welding(laser with GTAW, GMAW, or PTAW) have thepotential of being used with Ti alloys. These weldingprocesses have less heat input than GTAW or GMAWPand therefore less distortion. However, the cost of ahigh-power laser (>1 kW) may make fabrication costtoo expensive to use in production.EWI has recently investigated hybrid welding of Tialloys but using very low laser powers. The objectiveof this is to stabilize the GMAW-P process to achievea high quality weld using a low-power laser (<500 W).Being able to use a low-power laser to achievedramatic improvements in the GMAW-P welds couldresult in a wider use of fabricated structures. This lowpowerlaser-hybrid approach could be used to fabricatestructures as an alternative casting or other weldingprocesses. This could impact aerospace,petrochemical, medical, and defense manufacturerswhere lower manufacturing cost are of interest.