Research on gripping conditions in profile ring rolling of raceway groove

Ring gripping means that under the pressure of roll and friction, ring grips the rolling gap and produces rotating rolling motion, thus ring thickness receives equal rolling and the outer diameter expands equally, and this is a sufficient condition for ring rolling forming. In this paper, gripping course in profile ring rolling of raceway groove is analyzed based on ring rolling principle and static theory. The gripping mechanical model for profile ring rolling of raceway groove is established, and gripping conditions are researched according to the geometrical relationship in rolling. The results indicate that ring could be ensured to continuously grip the gap in rolling by controlling feed per revolution and preventing it from exceeding the maximum feed per revolution allowed by ring gripping. Furthermore, influencing factors of gripping conditions are analyzed. At last, the experiments and the FE simulation for profile ring rolling of raceway groove are performed to testify the validity of gripping conditions. Both the experimental and simulation results show that when feed satisfies gripping conditions, ring can continuously grip the gap and be formed by rolling. Otherwise, ring cannot grip the gap and is squashed between the rolls. The results of this research provide a theoretical basis for design of technological parameters of profile ring rolling of raceway groove.