ANALYSIS OF MECHANICS IN BALL SPINNING OF THIN-WALLED TUBE

摘要

Ball spinning is applied to manufacturing thin-walled tube with high precision and high mechanical properties. On the basis of plastic mechanics,by simplifying ball spinning of thin-walled tube as plane strain problem,slab method is used for the purpose of calculating the contact deformation pressure. The spinning force components,the torsional moment,the deformation power and the deformation work are calculated further as well. The influence of the two important process parameters such as the feed ratio and the ball diameter on the spinning force components is analyzed in order to further control the spinning force components by regulating the two process variables during the ball spinning process. The stress and strain state in deformable zone as well as mechanics boundary conditions in ball spinning are obtained. The effect of the three spinning force components on the formability of the spun part is analyzed and validated through the ball spinning experiments. The theoretical and experimental results show that the radial spinning component plays a significant role in ball spinning of thin-walled tube,and the mechanics situation in backward ball spinning contributes to enhancing the plasticity of the metal material,but that in forward ball spinning contributes to advancing the axial flow of the metal material.