Abstract
In the bulging-pressing forming process of heavy truck axle housing, the technology of hydroforming with axial-circumferential feeding solves the problems of large wall thickness thinning rate in the middle part and cracking on the rear cover. However, there exsits some defects of depressions and squeezed marks on the upper side of the preformed tube in practical application, and the reasons are not clear. In this paper, the causes of the defects in the hydroforming were revealed through analyzing the forming quality of the tube blank. According to that, the design methods of the D-shaped cross section preformed tube and the non-equal width control die were given.The influences of height coefficient, beam coefficient and width coefficient of upper control die on forming quality of preformed tube blank were revealed by finite element simulations, and then the reasonable ranges of the three coefficients were determined. The D-shaped cross section preformed tube was successfully prepared by the preparation experiment of heavy truck axle housing tube, whose hidden dangers of depressions and squeezed marks were eliminated, and the simulation results were consistent with the experimental results. The pressing-forming experiment was carried out, and all dimensions meet the design requirements of the axle housing tube.