A model to describe hardening behavior of Zircaloy-4 tube during cold pilgering process

A macroscopic hardening model is proposed to describe the hardening behavior of Zircaloy-4 tube for better modeling of cold pilgering process. The model can describe the deformation under a large strain condition. Model parameters have been obtained from uniaxial tension tests coupled with its corresponding finite element analysis. The difference of force-displacement curve between test and finite element analysis is minimized iteratively through adjusting necking point. In addition, the influence of strain rate and temperature on hardening behavior is also introduced into the hardening model. Finally, the model is utilized for the finite element analysis of cold pilgering process. The predicted results on rolling force and tube dimensions during cold pilgering are compared to experimental ones. The error of rolling force between simulation and experiment is less than 1%. The conical dimension curve (wall thickness/ outer diameter) agrees well with the curves of experimental measurement, which validated the established hardening model.