3d Finite Element Simulation Of Rail Wheel Forming Process

Wheels play a key role in a railway vehicle especially on the safety aspect. This is especially true for the rapid development of China's high-speed railway industry. To satisfy the ever increased requirements on the reliability and durability, hot forming becomes the most competitive routine for manufacturing of rail wheel. However, there is only limited research focus on the rail wheel forming and the understanding on the wheel rolling process is still limited, which result many unresolved problems in the manufacturing process.This thesis reports recent research on the rail wheel forming process. Firstly, the material properties including flow stress is obtained by using a hot compression test. Followed by that, the wheel preforming and forging FE model is established in DEFORM-3D and the material flow behavior is investigated. The effect from process parameters, including the initial slug and forging die positioning, the deviation of forging die, the weight of slug, initial temperature and forging speed are studied. The simulation results are verified against experiment results.To obtain a stable wheel rolling process, the feed rate planning of pressure roll is investigated based on the constant wheel diameter growth speed. A 3D finite element model of rail wheel rolling is established using DEFORM-3D and this model is verified with physical model by comparing the rolling force. In addition, the material flow behavior and the effect from initial temperature in the rolling process are studied. In order to analyze the cause of folding defect, a prediction criterion is proposed to identify the possible area with folding defect based on the change of elemental surface area during rolling process. The simulation results suggested certain accuracy of proposed criterion and the robustness of this algorithm is verified by physical rolling experiments. Suggestions on avoiding the folding defects are also given on improving the wheel forming process.