Heat transfer simulation for continuous Laser and GTA welding of 22MnB5 steel thin structure

In this research, both equivalent heat sources due to continuous Laser and GTA (Gas Tungstun Arc) welding have been identified. Three-dimensional thermal simulations model has been proposed and applied to 22MnB5 steel thin plates. A 3-D conical with cylindrical shell heat source model and Goldak double-ellipsoid volumetric heat source have been chosen and used, respectively, for Laser welding and GTA welding in finite elements models. The solved model provides the temperature fields and therefore the molten zone shape.

For both models, the equivalent heat source parameters have been determined using the experimental results. Both equivalent heat sources have been adjusted according to thermocouple temperature measurements and macrographic cross-section observation. Numerical results have a good agreement with experimental measurements in terms of temperature distribution and weld bead shape and size. These results validate the choice of equivalent heat sources for the two welding types.

Equivalent heat sources identification is the preliminary work, final aim of this work is to introduce temperature fields obtained by thermal model into a mechanical model in order to predict residual stresses induced by welding processes.