A new cylindrical ring rolling technology for manufacturing thin-walled cylindrical ring

• A new ring rolling technology for manufacturing thin-walled cylindrical ring is proposed.
• The stability and final roundness of the deformed ring can be guaranteed easily by the inner surface of the constraint roll without the guide rolls and complicated control schedule.
• The proposed process can achieve a large increase in both the ring diameter and height.
• Under the constant radial deformation, different axial and circumferential deformation distribution can be achieved by changing the rolling ratio.

Ring rolling is an advanced incremental metal forming technology used to manufacture precise seamless rings. Generally, it is classified as two types. One is pure radial ring rolling in which the ring mainly produces the deformation of thickness reduction and diameter expansion and its height basically remains unchanged. The other is radial–axial ring rolling in which the ring produces the deformation of thickness reduction, diameter expansion and height reduction. Obviously, it is difficult for the above two types of ring rolling processes to achieve a large increase in the ring height. Therefore, this paper proposes a new cylindrical ring rolling process which can achieve a large increase in both the ring diameter and height. For evaluating the proposed process, a 3D elastic–plastic FE model of cylindrical ring rolling is first established and its validity is verified by the experiment carried out on a vertical NC ring rolling machine. Then, some fundamental forming characteristics, such as the geometry evolution and strain distribution of the ring, contact characteristics between the rolls and ring and power parameters, are investigated based on this reliable 3D FE model. Finally, the effect of a critical process parameter, axial rolling ratio (circumferential rolling ratio), on the cylindrical ring rolling process is revealed numerically. Through the above analysis, three highlights of the proposed process can be summarized as follows: (1) The stability and final roundness of the deformed ring can be guaranteed easily by the inner surface of the constraint roll without the guide rolls and complicated control schedule. (2) The proposed process can achieve a large increase in both the ring diameter and height. (3) Under the constant radial deformation, different axial and circumferential deformation distribution can be achieved by changing the axial rolling ratio (circumferential rolling ratio).