High power lasers can be used to produce high quality, distortion free, deep penetrating welds in thick steel plate. The capital cost requirements for a laser welding system can potentially be reduced by employing laser assisted arc welding. This hybrid process, which combines inexpensive arc welding energy with more expensive, but highly controllable laser energy, can produce deeper welds for a given heat input to the base material as compared to conventional arc welding processes.
We have examined the effect of several process parameters on the weld bead physical characteristics obtained by combining the laser energy from a five kilowatt, continuous wave, carbon dioxide laser with the arc energy from a gas metal arc welding (GMAW) machine. As expected, laser assisted gas metal arc welding (LAGMAW) produced deeper penetrating welds than either the GMAW or laser welding processes at equivalent heat inputs during bead on plate trials on 25 mm thick steel plate. Weld penetration of up to 8 mm was achieved using a heat input of approximately 1 kJ/mm and a welding speed of 16.9 mm/s. To achieve penetration similar to LAGMAW using laser or gas metal arc welding alone, roughly 40 to 50 percent higher heat input is required.