Preliminary evaluations on laser - Tandem GMAW

Recently there has been considerable research and development activity in the use of lasers for welding operations, turning this process into an important tool for a variety of applications. Although it is possible to use lasers as a unique source of heat to promote union of materials, the combination of the beam provided by a laser system with an arc welding process has been studied widely and applied in the so-called hybrid welding systems. Generally, the final result of such a combination is an increase in the weld penetration depth, width and welding travel speed. Despite these advantages, there are many issues still requiring further research and development concerning the use of hybrid welding using laser and arc welding, including a more comprehensive understanding of the various welding phenomena involved and the exploitation of new combinations. This paper describes an approach for hybrid welding combining a laser with tandem GMAW, in particular placing the laser beam between the tandem GMAW wires. This hybrid process variation is described and some basic aspects regarding its performance are discussed. The laser beam was found to have a positive effect on the appearance of the weld heads produced and best results are obtained if the laser is located halfway between the leading and trailing wires. A 10mm inter-wire distance was found to be the most appropriate of the separation distances tried. The hybrid process approach was able to increase the welding travel speed or penetration depth significantly in comparison with tandem GMAW (operating in pulsed mode)