Influence of the welding speed on the distortion of thin stainless steel plates-Numerical and experimental investigations in the framework of the food industry machines

This paper concerns the welding of thin plates of machines for the food industry. A 3D finite elements model was developed to analyse the thermomechanical behaviour of 316L steel during the TIG welding process. The objective is the evaluation of the influence of the process parameters (such as the welding speed) on distortions induced by the welding operation. The mobile welding source was represented with a Gaussian profile, whose parameters were calibrated using the response surface of a design of experiments (DOE) method in order to decrease differences between experimental and modelled characteristics of the weld (thickness and width). The change of the reference temperature of the elements that have reached the melting point was found to be an important aspect allowing considering the stress relaxation induced by the material local melting and allowing the prediction of a correct distortion after cooling down. The results are quite realistic and a relative difference of only 5% between measured and calculated values of the welded plate deflection was obtained.