ENCYCLOPÉDIE DE LA RECHERCHE SUR L’ALUMINIUM AU QUÉBEC 2013 | Page 72

70 DÉVELOPPEMENT, OPTIMISATION ET INTÉGRATION DES PROCÉDÉS DE FABRICATION ET DE CONCEPTION DEVELOPMENT, OPTIMIZATION PREDICTION DE LA STRUCTURE AND PROCESS INTEGRATION OF MANUFACTURING AND DESIGN DES JOINTS DE SOUDURE FSW PRÉDICTION DE LA STRUCTURE DES JOINTS DE SOUDURE FSW (Prediction of FSW joints structure) PREDICTION OF THE STRUCTURE OF FSW WELDED JOINTS A. TONGNE1, M. JAHAZI1, C. DESRAYAUD2 Auteur 1, Author2 2 1 Ecole de Technologie Supérieure 1 Département et Institution 1 Ecole Nationale Supérieure des Mines de saint Etienne 2 department and Institution 2. Objectives Optimising Friction Stir Welding (FSW)  By studding material flow during the process thanks to the weld structures  Modeling these structures mainly the banded structure observed in the weld longitudinal cross section whose transverse cross section exhibit the “onion rings” Numerical studies Procedure Tool pin: Stirs the material at the interface Tool shoulder : Generates heat by frictionsub surface shearing Tool Tool pin FSW steps  Banded structure phenomena are describe by imposing periodical boundary and time conditions.  The model is based on thermal balance equation in which the mechanical part is described analytically by intuitive velocity field of material flow. Resolution is operated on Abaqus Standard. Tool shoulder  We use Matlab for identifying the postulated velocity fields and the maximum strain rate reached by any particle. Experimental Studies Z direction (mm)  A trigonal pin was used to weld Aluminum alloy AA-6082-T6.  Welds were observed in different section with optical microscope Tool RS AS Aluminium plates Y direction (mm) a) “Onion rings” Support Welding Fixture Amèvi Tongne Mohammad Jahazi École de technologie supérieure A Christophe Desrayaud École Nationale Supérieure des Mines de Saint-Étienne RS Trigonal tool AS A b) Banded structure Maximum strain rate (s-1) field predicted by the model. a) transverse cross section viewer b) Horizontal Longitudinal cross section viewer “Onion rings” microstructural visualization in the weld transverse cross section. Tool velocities 2000rpm and 600mm/min A-A Conclusions and outlook  The model predicted well FSW weld features.  This can help to choose optimal parameters in order to avoid weld defects and experimental wastes mainly for new applications . Welding direction Banded structure microstructural visualization in the weld bottom horizontal longitudinal cross section (distance from one band to another equal to the third of the tool advance per rotation)  Additional elements on material flow around the shoulder zone will be added to the model .  A microstructure model is also in development for predicting grain size for banded structure visualisation Journée des étudiants – REGAL The success and expansion of FSW (Friction Stir Welding) process also find their La réussite et l’expansion du procédé de soudage FSW (Friction Stir Welding) Palais des congrès de Montréal, QC, Canada, 22 complexity of selecting proper or optimal welding parameters. obstacles in the octobre 2013 trouvent aussi leurs obstacles dans la complexité du choix des paramètres de Thus, we set up a model of FSW to predict the structure of FSW joints, especially soudage adéquats voire optimaux. C’est ainsi que nous avons mis en place the onion rings observed in the nugget that affect the mechanical properties un modèle de soudage FSW permettant de prédire la structure des joints de of welded joints. The model was developed in periodic by applying periodical soudure FSW, plus particulièrement les « onion rings » observés dans le noyau boundary and time conditions to describe the formation of the banded structure qui influencent les propriétés mécaniques des joints de soudure. Le modèle a été whose cross-section shows the onion rings. The model results showed a similarity développé en régime périodique en appliquant des conditions aux limites et des between the field of the maximum strain rate reached by any particle and the conditions temporelles périodiques afin de décrire la formation de la structure microstructure of our test samples. A microstructural model is being developed en bandes dont la coupe transversale montre les « onion rings ». Les résultats for the prediction of grain size from the data of the current model. du modèle ont montré une similitude entre le champ de vitesse de déformation maximale atteinte par les particules et la microstructure des échantillons de nos essais. Un modèle microstructural est en cours de développement pour la prédiction de la taille des grains à partir des données du modèle actuel.