Abstract: Aiming at the lack of calculation model of deformation force during the deformation process of “extrusion upsetting”, which makes it impossible to carry out the current situation of equipment selection, process design and tooling design, the load solving model in the process was established. Deform-3D simulation software was used to study the effects of blank size, forming part size and friction factor on the forming load. Due to the special characteristics of the deformation feature of local injection upsetting deformation, the traditional mechanical model can not be calculated, by analyzing the mass flow law in the deformation process, a new assumption of boundary conditions is proposed. The mechanical equilibrium equation of the tiny unit cell is established by the principal stress method, so as to realize the establishment of the load model, and the physical experiment is verified by two typical magnesium alloys, AZ80 and VW124A. The trend of the model curve is consistent with that of the simulation curve, which indicates that the proposed assumption of boundary conditions is reasonable and can be used for the calculation of the force energy of the dramatic deformation of “extrusion upsetting”. However, the trend of the physical experiment is different because the material properties are affected by the strain state. The deviation between the physical experimental results of the forming load and the calculated results is less than 10%, which shows the reasonableness of the proposed model and provides theoretical basis for the equipment selection and process design.

Key words: “extrusion upsetting” severe deformation, metal flow, deformation assumptions, forming load model