brings the workpiece above the recrystallization temperature is also used to perform the heat treatments so that any subsequent heat treating is unnecessary. Types of heat treatments include the production of a fine grain structure; controlling the nature, size, and distribution of various transformation products (such as ferrite, austenite, pearlite, bainite, and martensite in steel); inducing precipitation hardening; and, controlling the toughness. In order to achieve this the entire process must be closely monitored and controlled. Common variables in controlled rolling include the starting material composition and structure, deformation levels, temperatures at various stages, and cool-down conditions. The benefits of controlled rolling include better mechanical properties and energy savings. Forge rolling Forge rolling is a longitudinal rolling process to reduce the cross-sectional area of heated bars or billets by leading them between two contrary rotating roll segments. The process is mainly used to provide optimized material distribution for subsequent die forging processes. Owing to this a better material utilization, lower process forces and better surface quality of parts can be achieved in die forging processes. Basically any forgeable metal can also be forge-rolled. Forge rolling is mainly used to preform long-scaled billets through targeted mass distribution for parts such as crankshafts, connection rods, steering knuckles and vehicle axles. Narrowest manufacturing tolerances can only partially be achieved by forge rolling. This is the main reason why forge rolling is rarely used for finishing, but mainly for preforming. Characteristics of forge rolling: high productivity and high material utilization good surface quality of forge-rolled workpieces extended tool life-time small tools and low tool costs improved mechanical properties due to optimized grain flow compared to exclusively die forged workpieces Mills A rolling mill, also known as a reduction mill or mill, has a common construction independent of the specific type of rolling being performed: Work rolls Backup rolls – are intended to provide rigid support required by the working rolls to prevent bending under the rolling load Rolling balance system – to ensure that the upper work and back up rolls are maintained in proper position relative to lower rolls Roll changing devices – use of an overhead crane and a unit designed to attach to the neck of the roll to be removed from or inserted into the mill. Mill protection devices – to ensure that forces applied to the backup roll chocks are not of such a magnitude to fracture the roll