Welding of thick austenitic stainless steel using Nd:yttrium-aluminum-garnet laser with filler wire and hybrid process

Autogenous laser welding has shown many advantages over traditional welding methods in numerous applications. However, there could be even more applications, but due to the power levels of present high power lasers, depth of penetration is limited. One way to overcome this limitation is to use multipass laser welding, in which a narrow gap and a filler wire are applied. By this process thick sections can be welded with a smaller heat input and therefore with smaller distortions, and the process seems to be very effective compared to "traditional" welding methods. Another way to increase penetration and fill the groove is by using the so-called hybrid process, in which laser and GMAW are combined. In this study thick section austenitic stainless steel is welded using a multipass technique with filler wire, and also by utilizing a hybrid process. For narrow gap conditions, groove angles of 8degrees, 10degrees, and 12degrees, are used with a partially grooved V joint. Parameters (e.g, filler wire feeding, placement of wire, and arc) are varied. Results of the experiments are presented and phenomena of the process, as well as reasons for weld defects, are pointed out. (C) 2003 Laser Institute of America.