Abstract: To accurately characterise the quantitative relationship between the deformation behaviour of tubes in hot gas bulging and process parameters, a new method for modelling the hot gas bulging process parameters of 6061 high-strength aluminum alloy tubes based on visco-plastic constitutive is proposed. Meanwhile, the quantitative mapping relationship between different process parameters and material deformation behavior was established. The hot gas bulging process experiment of 6061 aluminum alloy with complex-shaped tubes is carried out. The defect occurance and thickness distributions under the typical process parameters, i.e. forming temperature, pressuring rate and pressure are obtained. Based on the experimental results, models of the visco-plastic constitutive correlation of AA6061, the pressure rate-strain rate and the hot gas bulging simulation are established. The results have shown that formability of tube increases significantly with increasing temperature, and the strain during deformation is lower than ductility limt of the model computated value. The higher the pressurizing rate, the greater the equivalent strain rate, and the thickness uniformity of parts is improved using strain rate hardening. The established hot gas bulging process parametric model enables to provide an effective quantitative analysis method for the process parameter selection of hot gas bulging forming for complex-shaped hollow components.

Key words: hot gas bulging, process parameters, aluminium alloy, visco-plastic constitutive model, thickness