FE analysis of 6063 aluminium profiles with complex cross-section during online quenching processes

Thermal-elastic-plastic finite element (FE) theory and solution of thermal-structural coupled field were investigated on the basis of commercial software ANSYS. The FE model used to solve the transient air and water cooling processes of extrusion profiles was built through developed programs on the basis of ANSYS. The calculated temperature and displacement of a plate during water cooling are in good agreement with the measured value and the FE model is reliable. Consequently, the temperature, displacement and equivalent stress of a complex cross-section profile from a plant during online quenching process were investigated. Thickness and boundary conditions difference leads to the temperature difference across the section increases up to about 120 degrees C firstly and then decrease to less than 40 degrees C. For the complex cross-section profile, the non-uniform deformation is more obviously and the larger thermal stress is the main reason of plastic deformation, fracture generation and occurrence of higher residual stress. A method used external stretching force to improve the distortion was also proposed in quenching processes and the displacement and equivalent stress is reduced significantly through external stretching force. However, larger external stretching force perhaps results in more serious distortion and fracture.