Numerical Simulation of Temperature Distribution and Residual Stress in Laser Beam Welding AA6061 and Ti-6Al-4V and Optimization of Welding Processes

Background: Since the combination of its rapid processing speed and high energy input, laser beam welding is considered advanced and suitable for welding thin and lightweight metals. The residual stresses deposited in the parts as a result of rapid heating and cooling render laserwelded components susceptible to fractures and deformities. Objective: In this patent, the modelling of the laser beam welding process during the joining of Ti- 6Al-4V and AA6061 dissimilar metals to analyze the effects of the welding process on residual stress and elastic strain by considering beam radius, beam offset, welding speed, and beam power as input parameters. Methods: The 3D model of the Ti-6Al-4V and AA6061 was developed using CATIA V5R16 software and beam radius. Beam offset, welding speed, and beam power are the input parameters considered, and the output parameters are stress and elastic strain. Design Expert is used to design the experiment. ANOVA was used, and a mathematical model was developed to analyze the performance characteristics of the welding process. Results: The results revealed that increasing the laser power increases residual stress, whereas it decreases with increasing the other parameters. The maximum average equivalent von Mises stress was 288.79 MPa, which is near the yield strength of AA6061. The optimum welding conditions selected for minimum possible residual stress is 1600.003 W, welding speed 0.05 m/s, beam radius 0.014 m. Conclusion: Based on the current observation during the simulation of joining dissimilar metals, the flow temperature along the weld line and weldment shows uneven distribution due to the dissimilarity of temperature-dependent properties of materials. The increased laser power leads to an increase in residual stress.