Analysis of tube spinning process

Abstract

Tube spinning is a continuous bulk-forming process used to produce seamless, cylindrical, conical and contoured tubes. Over the last six decades, tube spinning process has been applied in a wide range of engineering applications; especially in automotive, aerospace and nuclear industry. However, the process has seen little change, and despite a large volume of literature investigating the process, understanding of the process mechanics is limited and the key references have been published about 50 years ago. This thesis aims to provide an insight into tube spinning process and its process mechanics, looking into mechanism of deformation, subsequently using this insight to explain phenomena observed in tube spinning. To do this, tube spinning was investigated in detail using three different theoretical investigation methods. To understand the effects of process parameters on tube geometry in terms of tube geometry: bell-mouth, material accumulation and wave phenomena, a set of physical trials was performed with varying process parameters: feed ratio, reduction ratio, staggered spinning and lubrication. The results show that bell-mouth, material accumulation and wave increase with an increase in feed ratio and reduction ratio, number of passes and decrease when staggered roller setup is used. However, the results indicate that there is no relationship between friction (lubrication) and dimensional accuracy. Also, to give insights into the mechanics of tube spinning process, numerical and analytical modelling approaches have been developed. The process is investigated using a numerical model with an implicit time integration and Lagrangian scheme. Full tube model and a set of fast angular segment tube models have been developed and validated against physical trials in terms of tube profile and forming forces. According to the tube profile comparison between the model and physical trial, the results show that the model agrees with the physical trial to within %97.