Research On Ball-Spinning Forming Craft Of Thin-Walled Tube

With the rapid development of modern spinning technology, power spinning has been an advanced plastic forming process in the field of precise metal forming technology of aerospace, aviation and military industry. As a power spinning process which uses balls as deformation tools, ball-spinning has become the new process for manufacturing high-strength, high-precision thin-walled tube. It has a pivotal position in the aerospace industry, automotive and civil industries.Based on finite element theory and the practical production process in this article, the analysis software DEFORM-3D is applied to build the three dimensional elastic-plastic finite element model of backward ball spinning process for GH4169 tube by using the numerical simulation method. It reveals the metal flowing rule in backward ball spinning process and the rule of stress-strain distribution in the wokpiece.The influences of the variation of technical parameters such as axial feed ratio, reducing ratio, spindle speed and ball diameter on the equivalent stress, equivalent strain and spinning forces in the tube spinning process have been analyzed in the paper. The emergence of some common quality defects, such as piling, surface ripple, port bellmouth, etc is explained, and focusing on quantitative analysis of piling. It avoids the defects through comprehensive consideration and reasonable matching parameters. It provides the basis for the selection and optimization of spinning process parameter.According to finite element simulation results, for the processing technique described in this article, the simulation results are verified through experiments. As a result of the reasonable spinning process parameters, it avoids the spinning defects and result in finish products with higher quality. The numerical results agree well with the spinning experimental results, and have achieved the anticipated goal.At the same time, the ball-spinning process of stainless steel OCrl 8Ni9 tube whose diameter and wall thickness are 30mm and only 0.2mm, respectively has been investigated. It has focused on the analysis of effects of ball diameter, reducing ratio, axial feed ratio and spindle speed on the results of forming. The numerical results show that smaller wall thickness may result in quality defects such as the skin splinter, fracture, etc. The parameters like reducing ratio, axial feed ratio, etc. should be taken as a smaller value.