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

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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.