Elastic–plastic finite element analysis of cold ring rolling process

Although cold ring rolling is used in the manufacturing of bearing races, research on this process has been limited. In this study, the fundamental characteristics of cold ring rolling are made clear by the finite element method. Steel rings with rectangular cross-sections are rolled on a mill with a driven mandrel and a work roll. The entire ring is analysed under the plane-strain condition. An elastic–plastic constitutive equation is used on non-steady-state scheme. It is found that at the beginning of the rolling, the ring vibrates irregularly. The reduction in thickness increases linearly during the first revolution of the ring, then increases slightly from the second revolution. At the early stage of rolling, the equivalent strain is higher at both surfaces and distributes inhomogeneously along the circumference. In the roll gap, the radial stress of surface elements shows a peak at the middle of the contact arc. The spatial distribution of stress components approaches the steady-state after a few revolutions. Outside the roll gap, generally compressive circumferential (hoop) stress acts on the outer surface, while tensile stress acts on the inner surface. The stress components change periodically with the revolution. The fundamental characteristics of the cold ring rolling process are discussed.