Research on microstructure evolution of the three-roll skew rolling hollow axle

To optimize the comprehensive mechanical performance of the rolled piece in three-roll skew rolling (TRSR), a more exquisite and uniform microstructure of the rolled piece must be obtained. In this paper, the evolution laws of the microstructure are obtained by exploring the forming process of TRSR hollow axles. First, the optimum process parameters for the microstructure of the rolled piece are obtained by orthogonal testing. Second, taking the hollow axle of LZ50 steel as the research object and combined with the results of the orthogonal test, a thermal-force-microstructure coupled finite element model of the TRSR hollow axle is established by adopting SIMUFACT software. Third, a total of nine points are selected along the axial and radial directions of the rolled piece as observation points to research the variation laws of the average grain size at different positions with time. Fourth, the evolution and distribution laws of the average grain size and recrystallization volume fraction during the TRSR of hollow axles are researched. Finally, combined with the TRSR experiment, the variations in microstructure in the experiment are consistent with the simulation results, which verifies the reliability of the model.