Study on forming quality of three-roll skew rolling hollow axle

To optimize the wall thickness quality of three-roll skew rolling (TRSR) hollow axle, this paper explores the wall thickness quality from the perspective of forming mechanism and test design analysis. First, the finite element model of TRSR hollow axle was established based on SIMUFACT software. Second, the evolution characteristics of workpiece wall thickness under various initial wall thickness conditions were found by single factor test. Third, based on the metal flow velocity, the formation mechanism of wall thickness at different positions of the workpiece is discussed, and the causes of various wall thickness defects are found. Fourth, the wall thickness quality evaluation index was proposed and the orthogonal test was carried out. The relationship between process parameters and wall thickness quality was obtained. Fifth, a method of using irregular billets was proposed to improve wall thickness quality. The results indicate that the diversity of initial wall thickness of the workpiece can lead to two phenomena: wall thinning and wall thickening. A larger wall thickness will result in thinning of the wall thickness, while a smaller wall thickness will result in thickening of the wall thickness. The method of adjusting process parameters has limited impact on improving wall thickness quality. The method of using irregular billets can greatly improve the wall thickness quality of the hollow shaft.