Information about the shape, dimension and residual stresses in a component after the different manufacturing steps are of great interest in order to reducing cost and time spent during product development. Information about the residual stresses also give input for lifetime prediction, which is important in the aerospace industry. Process parameters and different fixture set-ups can be evaluated without doing a large number of experiments by the use of a virtual model. The finite element method has been used to predict the material response due to welding and the use of this method have shown good correlation between measured and calculated results, especially considering residual stresses. Industrial applications do often involve complex geometrical shapes and thereby make this type of simulations time consuming. Therefore it is of great interest to investigate if simple models can replace detailed analysis at least during the preliminary design stages when a qualitative correct model can give useful result in a short period of time. Comparison between results from 2D, 3D-shell and 3D-solid models are compared in this study and conclusions are drawn about the applicability of the different models.