Finite Element Analysis Of The Welding Temperature Profiles And Thermal Distortion In Laser +GMAW Hybrid Welding Process

Nd:YAG laser +GMAW hybrid welding process which combines heat sources of both the laser and the GMAW arc to act on the same position of the workpiece makes full use of their advantages and overcomes their shortcomings, so that it is becoming one of the new welding process of high quality anf efficiency. In this study, the numerical analysis model of the hybrid welding process is developed with considering its characteristics. And the model could be the basis for optimizing the parameters of this new welding process.From the point of view in macroscopic phenomena of heat transfer, suitable and adaptive volumetric heat source mode is developed to completely reflect the geometric characteristic of hybrid weld. A combined volumetric heat source model is proposed, i.e. a double-ellipsoidal body mode is used at the upper part of the workpiece while a linearly-increased peak value of heat flux in Gaussian cylinder mode is employed at the lower part of the workpiece along its thickness direction. The temperature fields on the workpieces of different conditions are numerically simulated using the combined heat source "double-ellipsoid + linearly-increased peak value of heat flux in Gaussian cylinder". The calculated and measured weld dimension and geometry match well to demonstrate the reasonableness and suitability of the combined volumetric heat source mode.Based on the calculated temperature profiles, finite element analysis of themal distortion is conducted for hybrid welding, In hybrid welding process, the cross section,the longitude section,the top section and the total deformation of the workpieces are lower than those in GMAW when the weld penetration for two processes is nearly equal.It provides with basic data for the optimization of hybrid welding process and further verifies the advantages of hybrid welding process.