Basic experiments by hybrid welding to steels for shipbuilding

As in recent years researchers in the field of Laser-Arc Hybrid welding are increasing because of its various economical and technical advantages. In this present study, the author assembles a hybrid welding head by adding the tip of conventional TIG welding machine on the head of laser welding machine. Depending on the order of TIG tip and laser beam head there are two possible way to set the Hybrid welding head. One way is by making the hybrid head as the arc of TIG machine followed by laser beam and the other is by opposite setting of hybrid welding head. The hybrid welding is carried out in both TIG foregoing and following process and also by varying the distance between laser beam center and arc center of TIG welding specimen surface. Nd-YAG laser with a laser beam power of 3KW is used and varied laser-arc distance from 0 mm to 10 mm with fixing the TIG current as 100A. Test specimens is shipbuilding steel, AH32 of thickness 6 mm and bead-on-plate welding is carried out with fixing the other welding conditions such as defocused distance of laser beam, flow rate of shielding gas, speed of welding etc. The result shows that there exists a certain laser-arc distance that could improve welding heat input and thus increasing the depth of penetration.