车轮成形中预锻工艺及模具结构对终锻过程的影响

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

以铁路货车用HDSA车轮为研究对象,采用MSC Marc软件建立车轮模锻有限元模型,模拟分析原预锻工艺及模具条件下车轮模锻成形过程中金属的流动及变形力,研究预锻闭模间隙对终锻轮辋充满度及锻压力的影响,进而考察预锻模具结构尺寸对终锻的影响,优化闭模间隙及预锻模腔结构。结果表明:在原预锻工艺及模具结构尺寸下,终锻结束轮毂完全充满,轮辋型腔上下角部充满度较差;减小预锻闭模间隙可使预锻压力显著增大并使终锻时轮辋金属更多流向轮缘,轮辋上部的圆角充满度降低,限于预锻压力机的能力,原预锻模具结构下预锻闭模间隙的可调整空间小,通过调整闭模间隙改善终锻轮辋内圆角部位填充效果有限;减小预锻模具的轮辋型腔内径可显著减小预锻压力,利于提高终锻后轮辋上部圆角的充满度,且对终锻压力没有明显影响;增加预锻轮辋型腔的高度也能一定程度降低预锻压力,提高终锻后轮辋上部圆角的充满度,但会显著增大终锻压力。综合考虑,减小预锻模具轮辋型腔内径是优选方案,但还需考虑终锻模具轮辋型腔尺寸,两者不能差异过大。

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.