Theoretical and experimental analyses of a speed control model for continuous dieless drawing process of tapered pipes

A speed control model for continuous dieless drawing process of tapered pipes is established on the basis of the volume incompressibility principle of metal. The effects of drawing speed and other deformation process parameters on the volume of the deformation zone and the size of the tapered pipe were analyzed and verified by experiment. The results show that the drawing speed is related to the feed speed, the size of the blank pipe, the size of the tapered pipe and the hot-to-cold source distance. The drawing speed increases with time non-linearly. With an increase of drawing speed, the volume of the deformation zone declines;but with the hot-to-cold source distance lengthening and the feed speed increasing, the volume of the deformation zone changes significantly. When the proportion of feed speed to drawing speed is fixed, reducing the feed speed and enlarging the hot-to-cold source distance can reduce the dimension error and increase the control precision.