Thermo mechanical modeling on Friction Stir Welding using tool with flat faced pin in AA2024 T3

Abstract

Friction Stir Welding (FSW) is normally performed using a tool with newlinecylindrical tool pin. Shape and dimension of tool pin have higher influence newlineover the post weld properties of the weld joint. Although the tool pin s newlinepercentage contribution is limited in the total heat generation compared to newlineshoulder, considerable heat is produced by the tool pin also. Comparatively newlinetools with flat faced pin exhibit better weld quality than cylindrical shaped pin. newlineTotal heat generation in FSW is due to the friction between the tool and the newlineworkpiece as well as the plastic deformation of the material in the stir zone. newlineThis indicates that the temperature dependent mechanical properties of the newlinematerials to be joined depend on heat generation and the metal flow around newlinethe tool pin, which leads the analysis towards thermo-mechanical problem. newlineThis necessitates a promising thermo-mechanical model to optimise the newlineprocess parameters with respect to the chosen tool pin geometry. newlineComplicated geometrical boundary of the flat faced tool pin profiles with newlinerespect to the axis of rotation increases the complexity in thermo-mechanical newlineanalysis. The core objective of this research is to study the temperature newlinehistory on the heat affected zone as well as the stir zone on the usage of newlinedifferent polygonal pin profiles. Hence understanding the distribution of heat newlineand obtaining the temperature contours will assist in understanding the post newlineweld properties of the friction stir weld joints to optimise the process newlineparameters with respect to the tool pin geometry.Effects of temperature rise on post weld material properties were identified newlineusing hardness analysis at various points in the stir as well as the heat newlineaffected zones. Based on the results obtained on the joining process of newlineAA2024-T3, it was concluded that the increasing temperature in the stir zone newlinenot only improves tool durability but also it affects the property of the material newlinein the heat affected zone during the process.