多道次加载下TC6钛合金作动筒等温锻造成形规律

Isothermal forging laws on TC6 titanium alloy actuator cylinder under multi-pass loading

对TC6钛合金作动筒锻件进行单/双/三道次加载成形路径分析,以单道次加载成形中的载荷剧增处为转变点,并在该处改变凸模加载速度,采用双道次和三道次对作动筒进行加载成形规律研究。通过平均成形载荷与成形时间之比来表征成形效率,并对比得出较好的加载成形路径,研究该加载路径下的成形载荷大小与材料流动规律,结果表明:通过对比成形效率得出平均载荷较小、成形效率较高的3种多道次加载路径。从材料流动角度分析了单道次压下量为13%时载荷剧增是由于凸模顶端的水平面与工件开始接触,材料流动变慢导致的;而在压下量为72%时载荷增加是因为工件已经和凹模底部开始接触,大量材料继续向侧向实心凸起处流动,少量材料向上反挤成形作动筒的上端。最后,通过实验与模拟验证表明,作动筒锻件在双道次加载路径下的筒体成形良好,底部实心凸起处充填饱满。多道次加载能够发挥钛合金的超塑性能,提高成形效率,精确塑性成形。

The forming paths of single/double/three-pass loading for TC6 titanium alloy actuator cylinder forgings were analyzed.Taking the sharp increase point of load during the forming process of single-pass loading as the transition point,the punch loading speed was changed at this point,and the loading forming rules of the actuator cylinder was studied by double passes and three passes.Furthermore,the forming efficiency was characterized by the ratio of average forming load to forming time,and a better forming path of loading was obtained through comparison to research the forming load value and the material flow law under this loading path.The results show that three paths of multi-pass loading with smaller average forming load and higher forming efficiency are obtained by comparing the forming efficiency.From the perspective of material flow,it is analyzed that when the single pass reduction amount is 13%,the load increases sharply because the horizontal plane at the top of punch begins to contact with the workpiece and the material flow slows down.When the reduction amount is 72%,the load increases because the workpiece begins to contact the bottom of die,a large amount of material continues to flow to the lateral solid bulge,and a small amount of material is back-extruded upward to form the upper end of actuator.Finally,the experimental and simulation verification show that the actuator cylinder forgings is well formed under the double-pass loading path,and the solid bulge at the bottom is fully filled.It is confirmed that the multi-pass loading can exert the superplastic properties of titanium alloy,improve the forming efficiency,and better achieve the precise plastic forming.