Multi-wedge Cross Wedge Rolling Process of 42CrMo4 Large and Long Hollow Shaft

Large and long thick-walled hollow shafts are the key parts of industry equipments, which are formed by the multi-wedge cross wedge rolling (MCWR). In the present paper, first, the deflection angle equations of side-wedges applied at the multi-wedge cross wedge rolling of hollow shafts were derived, which lay important foundation for designing the MCWR mold. Second, the spreading angle's impacts on single-wedge cross wedge rolling (CWR) of thick-walled hollow shaft-part were discussed. And, compared to roll small diameter of hollow shaft, the ellipticity of the large and long thick-walled hollow shaft could be controlled, and the selection range could be extended. At the same time, it was also found that the ellipticity could also be controlled by empty top surface of the mold. At last, the FE model of double-wedge cross wedge rolling of large and long thick-walled hollow shaft was established. The forming process was simulated, and the ellipticity of symmetrical cross-section was monitored. The ellipticity of large and long thick-walled hollow shaft was controlled well. The simulated ellipticity of symmetrical cross-section is 4.98%, and the experimental ellipticity is 5.56%. The results indicate that it is feasible to produce large and long thick-walled hollow shafts with double-wedge CWR.