Effects of Heat Input Ratio of Laser-Arc Hybrid Welding on Welding Distortion and Residual Stress

For predicting welding distortion and residual stress generated by laser-arc hybrid welding, a series of experiments and analyses were carried out. A bead-on-plate welding was performed on SM490 steel by using a fiber laser and CO2 arc welding with changing their heat input ratio variously. The experiment was simulated by the thermal elastic-plastic analysis with the proposed simulation model considering the penetration shape by laser and arc separately. By using this model, the experimental results could be simulated with high accuracy. Therefore, the validity and generality of the numerical simulation model could be verified. The tendency and magnitude of angular distortion varied with the heat input ratio of laser and arc. The results indicated the possibility of the ideal heat input ratio of laser and arc for controlling angular distortion generated by hybrid welding. On the other hand, it was confirmed that the heat input ratio of laser and arc did not affect residual stress generated by hybrid welding.