Abstract
At present, hollow axles with constant hole diameter is mainly formed by turning thick-walled hollow tubes. This method of processing has low material utilization and processing efficiency. And heat treatment is required to improve the mechanical properties of hollow axles. To improve the material utilization and processing efficiency of hollow axles with constant hole diameter during the forming process, a new processing technique, three-roll skew rolling process, is proposed to form a hollow axles with constant hole diameter in this paper. The three-roll skew rolling process is a continuous plastic forming process, which has high material utilization and processing efficiency, and it can improve the mechanical properties of the rolled parts. Firstly, combining the working principle of three-roll skew rolling and the structural characteristics of hollow axles with constant hole diameter, the forming mechanism of hollow axles with constant hole diameter by three-roll skew rolling is described. Secondly, the finite element model of the hollow axles with constant hole diameter by three-roll skew rolling is established according to the dimensions of the hollow axles with constant hole diameter, the material characteristics of the hollow axles, and the stable rolling conditions of three-roll skew rolling. The process parameters of the hollow axles are also determined. Thirdly, according to each step position of the hollow axles, the forming process of the hollow axles with constant hole diameter by three-roll skew rolling is divided into 5 deformation stages. Lastly, the stress and strain field of each deformation stage of the hollow axles was analyzed. The results show that the dimensions of the hollow axles with constant hole diameter by three-roll skew rolling are very close to the designed dimensions, which indicates that the material utilization of the rolled hollow axles is very high. Along the rolling direction, the descending step of the hollow axle is easier to form than the ascending step, and the forming quality is also better. The surface metal of the rolled hollow axles flows faster than the internal metal. Areas with large stress and strain are mainly concentrated at both ends of the rolled hollow axles. And the magnitude of stress and strain gradually decrease from the surface to the center. The hollow axles with constant hole diameter by three-roll skew rolling has a good forming quality and high forming efficiency. The hollow axles with constant hole diameter is formed by three-roll skew rolling process, which has broad application prospects.
