Friction Stir Welding Thermal-mechanical Process Simulation And Application Of Aluminium Alloy

In this paper,based on the friction stir welding of aluminum alloy thin wall structure in rail transportation equipment manufacturing.The ABAQUS and HYPERMESH finite element softwares are used to simulate FSW process of 6082-T6 aluminum alloy plate.According to the characteristics of FSW,the heat source model was established.The fully thermal mechanical coupled method was used to simulate the welding process.At low rotation speed and welding speed conditions,the effect of different pins,shoulders,tilted angles and welding parameters were studied.There are two types of pins and shoulders,such as the cylindrical pin and conical pin,the flat shoulder and concave shoulder.The effect of high rotation speed and welding speed were also studied.The simulation results show that:Under the same process conditions,the 2 degrees of tilted angle makes the material in the welding area heating more uniform.The axial pressure on the material behind the tool is greater.It is more conducive to the thermoplastic flow of metal.Under the same process conditions,the concave shoulder produces heat more than the flat shoulder.The concave shoulder is better for the thermoplastic material flow.Under the same process conditions,the conical pin produces heat more than the cylindrical pin.The stirring effect of the material is better,and the material linear speed is greater.The equivalent plasticity of the welds are uniform,and the forming quality is better.When the welding is stable,thermoplastic materials at shoulder root are the most,and flow best.The maximum speed is located on the surface and near the outer edge of shoulder.The flow velocity of the material increases with the thickness decreases.The flow velocity at the bottom surface is the minimum.The typical defects,such as holes,tunnels and kiss bond,are easy to occur in the forward and bottom parts of the weld.The spindle roration speed should be increased,when the smaller tool geometric size is used.Under the condition of the spindle speed 2100 rpm and the welding speed 1100mm/min,the weld quality of 3mm thick plate is good.Under the condition of the spindle speed 1200 rpm and the welding speed 800mm/min,the weld quality of 5mm thick plate is good.