Modelling of Rolling

Warm or cold roll forming is a deformation process used for economic production of profiles, not only for structural purposes (e.g. angles, T-bars, channel sections etc.) but also for precision work, such as for turbine blades. For simple standard profiles, there are guidelines available and experimental findings for roll pass design and for working out the roll pass schedule from the starting pass to the finished section [5.1]. Flat rolling, too, has also been the subject of detailed investigation [5.2]. However, for designing complicated special profiles, the rolling tools are, as a rule, designed empirically. There are two reasons for this: 1.Roll forming is an experience-based technology, whereby improvements and developments have come about principally through a pragmatic approach by trial-and-error methods.2.Although numerous publications deal with lateral spread of the material within the roll gap, pre-determination of spread behavior during roll forming gives rise to considerable problems and is possible to a sufficient degree of accuracy only for special cases by the application of lateral spread formulae [5.3–5.6] or calculations on the basis of plasticity theory [5.7–5.9]. As lateral spread is influenced by many parameters [5.10] — geometry, friction, temperature, microstructure, yield stress — for new materials, there is no alternative but to determine lateral spread by experiment.