薄壁筒形件多道次滚珠旋压成形机理研究

Study on forming mechanism of thin-walled tube in multi-pass ball spinning

为研究多道次成形条件下薄壁筒形件滚珠旋压的成形机理,采用实验和有限元法相结合对薄壁筒形件多道次滚珠旋压的应力应变、旋压力和成形性进行了分析。结果表明:各道次下的等效应力和等效应变都是由旋压件的内表面向外表面逐渐增大,且随着旋压道次数的增加,等效应力和等效应变也都是逐渐增大;每道次的轴向旋压力随着滚珠行程的增加而增大,且各道次的旋压力也逐渐增大;多道次滚珠旋压时,由于采用较小的壁厚减薄量和材料的加工硬化,金属易于稳定流动,能够保证管坯的轴向伸长。因此,通过多道次滚珠旋压可实现大减薄量薄壁筒形件的旋压成形。

In order to study the ball spinning mechanism of thin-walled tube in the multi-pass condition,the stress and strain,the spinning force and the formability of thin-walled tube in multi-pass ball spinning were analyzed by combination of experiment and finite element method（FEM）.The results show that with the increase of ball stroke in each pass,both the stress and the strain increase gradually from the inside surface to the outside surface of the spun part.Moreover,the stress and strain increase with the increase of spinning pass.The axial force in each pass increases with the increase of ball stroke and spinning pass.In the multi-pass ball spinning,steady flow of metal can be formed easily because of using small thickness reduction and work hardening of the material,which can ensure elongation of the tube.Therefore,the spinning of thin-walled tube with large thickness reduction can be realized through multi-pass ball spinning.