Control method for centering rolls in radial-axial ring rolling process

Abstract

The control method of centering rolls was developed to ensure the circularity of rings and remove the process instability during a radial-axial ring rolling (RARR) process. The position control method is determined by the growth velocity of rolling rings and mathematical correlations among the key process variables, such as ring geometries, roll shapes, and feed rates of rolls. The moving coordinate of centering rolls were calculated by the growing velocity of an outer radius of the ring, VR, and the angle between the links of the ring’s center with the mandrel’s center and with the centering roll’s center, a, in the RARR process. The growth behavior of a ring and the angle provided moving coordinates for the centering rolls in real time. The hydraulic adjustment mechanism for establishing a successful RARR process is also proposed using the parameter design of the linkage assembly and beam bending theory. In order to verify the reliability of the control method, the FE-simulation under a FORGE software environment and ring rolling experiments of 42CrMo4 rings with an outer diameter of 510mm. The results show that these methods provided a high ring circularity and process stability.