Arc Welding of Dissimilar Metals: FEA and Experiments

Assuming an elliptical disk heat source, several results of theoretical and experimental investigations on heat transfer in copper - low carbon steel welded joints are presented in the first part of the paper. Using thin sheets, temperature variation in the thickness direction is negligible and heat flow is considered two-dimensional. Convection and radiation influence, and thermo-physical properties depending on the temperature are considered in the model. Measurements and visualization of the temperatures distribution have been made during welding using infrared thermography. The proposed theoretical method using finite element analysis was validated for the temperatures prediction in the welded joint. In the second part of the paper, the influence of the welding process on the structural modifications and grains' size in the heat affected zone (HAZ) of both base materials (BM) is described. Discussion on the graphs of temperatures variation vs. microstructural analysis enables conclusions on the potential undesired structural changes and related preventing measures. The asymmetric position of the heat source closer to the material having a higher thermal conductivity is an effective method for controlling the temperature field.