内花键齿形的振动辅助冷挤压细化晶粒的机理研究

Study on Grain Refinement Mechanism of Internal Spline Tooth Profile by Vibration Assisted Cold Extrusion

为研究轴向振动冷挤压工艺中成形件组织演化规律,采用元胞自动机方法模拟了轴向冷挤内花键成形过程中毛坯的微观组织演化过程。发现施加辅助振动的冷挤工艺加工出来的内花键平均晶粒尺寸明显小于无辅助振动时的平均晶粒尺寸。通过正交试验,分析了振动频率、振动幅值和挤压速度对成形件微观组织的影响规律。方差分析的结果表明,振动幅值对齿根部位晶粒平均尺寸影响最显著,而对节圆与齿顶部位晶粒尺寸影响最显著的分别是振动频率和挤压速度;振动频率对成形件齿根和节圆部位的平均晶粒均匀度影响最显著,挤压速度对齿顶的晶粒均匀度影响最显著。对辅助振动参数影响晶粒细化的机理进行了总结。

In order to study the microstructure evolution of the formed parts in the axial vibration cold extrusion process,the microstructure evolution process of the blank in the axial cold extrusion process is simulated by using the cellular automata method.It is found that the average grain size of internal spline processed by cold extrusion with auxiliary vibration is significantly smaller than that without auxiliary vibration.The effects of vibration frequency,vibration amplitude and extrusion speed on the microstructure of the formed parts are analyzed by orthogonal test.The results of variance analysis show that the vibration amplitude has the most significant influence on the average grain size at the tooth root,and the most significant influence on the grain size at the pitch circle and the top of the tooth is the vibration frequency and extrusion speed,the vibration frequency has the most significant influence on the average grain uniformity at the root and pitch circle of the formed part,and the extrusion speed has the most significant influence on the grain uniformity of the tooth top.The mechanism of the effect of auxiliary vibration parameters on grain refinement is summarized.