Problems and issues in laser-arc hybrid welding

Hybrid welding, using the combination of a laser and an electrical arc, is designed to overcome problems commonly encountered during either laser or arc welding such as cracking, brittle phase formation and porosity. When placed In close contact with each other, the two heat sources Interact In such a way as to produce a single high intensity energy source. This synergistic Interaction of the two heat sources has been shown to alleviate problems commonly encountered In each Individual welding process. Hybrid welding allows increased gap tolerances, as compared to laser welding, while retaining the high weld speed and penetration necessary for the efficient welding of thicker workpieces. A number of simultaneously occurring physical processes have been Identified as contributing to these unique properties obtained during hybrid welding. However, the physical understanding of these Interactions is still evolving. This review critically analyses the recent advances in the fundamental understanding of hybrid welding processes with emphases on the physical interaction between the arc and laser and the effect of the combined arc/laser heat source on the welding process. Important areas for further research are also Identified.