Equipment can be fully automated from billet heating through post-forge handling. Advanced ring rolling equipment can roll contours in both the inner and outer diameter of the ring, allowing for excellent weight reductions, material savings, and reduced machining cost. There is an infinite variety of sizes into which rings can be rolled, ranging from rollerbearing sleeves to rings of 25 ft in diameter with face heights of more than 80 in. Various profiles may be rolled by suitably shaping the drive and idling rolls. The workpiece completely fills the container and additional pressure causes it to travel through an orifice and form the extruded product.
Extruded product can be solid or hollow.
Tube extrusion is typical of forward extrusion of hollow shapes, and backward extrusion is used for mass production of containers. Piercing is closely related to reverse extrusion but distinguished by greater movement of the punch relative to movement of the workpiece material. Besides the primary forging processes, secondary operations often are employed. The mode of deformation is tangential compression. Because forging stock may assume complex shapes, it is rare that only a single die impression is needed.