Influence of tool geometry on the material flow during friction stir welding of copper
(English)In: Journal of Materials Processing Technology, ISSN 0924-0136Article in journal (Other academic) Submitted
The understanding of the material flow during friction stir welding of thick sections of copper is of great interest. Sweden plans to use this method to seal 50 mm thick copper canisters which will contain spent nuclear fuel. In this study two different weld tools are investigated. The first experiment uses a pin length of 52 mm and the second a pin length of 30 mm. The shoulder diameter, process parameters and materials are the same for both experiments. Experiments as well as FEM modelling work are reported. The experimental part includes a marker inserting technique using brass rod, which allows the material flow to be examined. After welding, the weld line is sliced, etched and examined by optical microscope. The experiments show more brass in the weld with shorter pin length and the nugget zone has different appearances in the two cases. A finite element model is applied to describe the temperature, material flow, dynamic viscosity, strain rate and shear stress in the welds. The outcome of the model and the feature of the experimental welds are compared showing a satisfactory result. The size of the thermomechanically affected zone is predicted by this model.
friction stir welding, copper, marker, viscosity, FEM simulation
IdentifiersURN: urn:nbn:se:kth:diva-12017OAI: oai:DiVA.org:kth-12017DiVA: diva2:294215
QS 201203282010-02-162010-02-162012-03-28Bibliographically approved