Abstract
The Laser-Arc hybrid welding of HSLA-590 steel has been studied using 2.4 kW CO_2 laser and MAG welding. Hybrid welding has a number of process parameters which are laser-arc distance, defocusing distance, laser power, travel speed, arc welding current, arc voltage, shielding gas and its flow rate, welding torch angle, wire diameter and so on. From the parametric study in hybrid welding of high strength low alloy steel, it is concluded in our study that the stable welding can be obtained when the welding parameters are controlled properly. Effects of welding parameters on bead shape and the hardness of weld metal at different welding speed, arc currents, arc voltages at constant laser power of 2kW and argon shielding gas flow rate 20L/min were investigated. The hardness of weld metal of then hybrid welding is lower comparing with those of Laser welding and MAG welding, because the heat input of hybrid welding is more than Laser welding and MAG welding individually under the same welding speed. In addition, a low carbon filler wire was used for decreasing the carbon content of weld metal. That means the hybrid welding is very useful for lowing the MAX. hardness and increase the toughness of welds.
