Effect of Pre-forging Process and Its Mold Structure on Final-forging Process in Railway Wheel Forming

Taking HDSA wheels for railway freight cars as the research object, MSC Marc software was employed to establish a finite element model of wheel forging, and the metal flow and deformation force during the wheel forging process under the original pre-forging process and mold design were simulated and analyzed. The influence of pre-forging die gap on the filling condition and forging pressure of the final-forged wheel rim was studied, and the influence of pre-forging die structure size on the final-forging was furtherly investigated, and the pre-forging die gap and its die cavity structure were optimized. The results show that under the original pre-forging process and mold structure size, the wheel hub is completely filled after final-forging, and the filling degree of the upper and lower corners of the wheel rim cavity is poor. The reduction of pre-forging die gap can significantly increase the pre-forging load and make the metal of the wheel rim flow from more towards the rim during final-forging, resulting in a decrease in the filling degree of the upper corner of the wheel rim, which is limited by the capacity of the pre-forging press, The adjustable space for the pre-forging die gap is small under the original pre-forging die structure. By adjusting the die gap, the effect of improving the filling of the inner corner of the final-forging wheel rim is limited. Reducing the inner diameter of the rim cavity of the pre-forging die can significantly reduce the pre-forging load, which is beneficial for improving the filling degree of the upper corner of the rim after final-forging, and has no significant effect on the final-orging load. Increasing the height of the pre-forged rim cavity can also reduce the pre-forging load to a certain extent and improve the filling degree of the upper corner of the rim after final forging, but it will significantly increase the final-forging load.Taking all factors into consideration, reducing the inner diameter of the pre-forging die rim cavity is the preferred solution, but it is also necessary to consider the size of the final-forging die rim cavity, and the difference between the two should not be too large.