闭式模锻成形理论及其关键技术研究

Study on forming theory and key technology of close-die forging

论述了闭式模锻成形原理及闭式模锻工艺特点。首先介绍了闭式模锻过程中锻件内应力-应变状态分析、应力球张量及应力偏张量计算公式以及两个应力与金属塑性、塑性流动变形的关系;然后解释了应力球张量即静水压力越大,金属塑性越好的机理;在阐述闭式模锻新工艺——流动控制成形的原理及特点的基础上,着重研究了如何解决闭式模锻时金属流动方向、流动距离及成形力的控制方法 3项关键技术;最后,通过直锥齿轮减压式冷锻、涡旋盘阻尼式热锻、机匣体减压式预锻及薄飞边阻尼式终锻与结合齿轮中空分流闭式模锻4个实例介绍了闭式模锻理论与3项关键技术的应用情况及效果。

The forming mechanism and process features of close-die forging were mainly discussed. The analyses of forging internal stressstrain states,calculation formulas of spherical stress tensor and deviatoric stress tensor,and the relationship between these two stress components,metal plasticity and plastic flow were conducted firstly. Then,the mechanism of the greater the spherical stress tensor（ hydrostatic stress） the better the metal plasticity was explained. On the basis of elaborating the mechanism and features of the new close-die forging process,i. e.,flow control forming,three key techniques for the control of metal flow direction,flow distance and forming load were studied emphatically. Finally,through four application examples,including cold forging of straight bevel gear with decompressive cavity,hot forging of scroll plate with back pressure,decompressive pre-forging and thin flash final forging of case,and close-die forging of conjunction gear with hollow decompressive cavity,the close-die forging theory and three key techniques were demonstrated.