Power Evaluation in a Hot Rod Rolling Process

The knowledge of the power required in a rolling process is the fundamental importance for the optimum planning of a rolling mill. Several models have been studied for the calculation of this parameter. These analytical models are characterized by very complex expressions, being many the parameters to consider in hot rolling: friction coefficient, temperature, roll radius, speed rolling etc. In particular, in a hot rod rolling process, the workpiece deformation is a three dimensional problem. In this paper, a hot rolling for low carbon steel rods, using grooved rolls, has been considered. Particularly, two different rolling passes, round-oval and oval-round have been taken into account. In order to predict the rolling power, Avitzur’s and Ekelund’s analytical models have been considered. These formulae are based on the monodimensional models used in flat rolling. Therefore, in order to reduce a tridimensional problem to a monodimensional one, two theories (Wusatowski and Shinokura Takay) have been used to determine the values of the equivalent heights of the incoming and outgoing workpiece. Finally, a finite element method has been used to simulate the rolling process. The analytical and numerical results are compared with experimental data relevant to rolling power that it has been obtained in two stands of an industrial plant for the production of concrete rebars