楔横轧阶梯空心轴径向压下量对内孔孔径变化影响规律

The influence of diameter reduction on inner hole diameter of step hollow shaft in cross wedge rolling

在阶梯空心轴的轧制中,径向压下量对内孔孔径的变化有重要的影响.基于Deform-3D软件建立了楔横轧阶梯空心轴成形的有限元模型,分析了阶梯空心轴的成形过程和金属流动规律,以轧后径向压下量和内孔孔径变化的关系为对象,研究了原始相对壁厚和轧制温度对该关系的影响规律.结果表明,随着原始相对壁厚的增大,相同径向压下量下内孔孔径变化减小;随着温度从950℃增加到1180℃,相同径向压下量下内孔孔径的变化先增加后减小,其中轧制温度为1050℃时最大.基于模拟计算结果,应用MATLAB对阶梯空心轴轧制过程中不同断面收缩率下的径向压下量与内孔孔径变化规律进行了拟合,给出了50%收缩率以上的统一拟合公式.随后的楔横轧阶梯空心轴实验结果与仿真结果误差在4.6%以内,验证了有限元仿真结果的准确性.

In the rolling process of stepped hollow shaft, the radial reduction has great effects on the change of inner hole size. With Deform-3D software, a finite element model of stepped hollow shaft forming in cross wedge rolling was developed, and the forming process and metal flow law of stepped hollow shaft were analyzed. The influence of original relative wall thickness and rolling temperature on the relationship between the radial reduction and the change of inner hole diameter was studied. The results show that with the increase of original relative wall thickness, the change of inner hole diameter decreases under the same radial pressure. With the increase of temperature from 950 to 1 180 ℃, the change of inner hole diameter increases gradually and reaches to the maximum at the 1 050 ℃ rolling temperature, and then decreases with the same radial pressure.Based on the simulation results, with the pressure reduction and the change of the inner hole size under different section shrinkage rates in the process of stepped hollow shaft rolling being fitted in MATLAB, a unified fitting formula for the reduction rate above 50% was given. The errors between the experimental results and simulation results were less than 4.6%, which verified the accuracy of the finite element simulation results.