ALGORITHM FOR CALCULATING THE ENERGY PARAMETERS OF THE PROCESS OF ROLLING HOLLOW BILLETS ON A CONTINUOUS MILL
The development of pipe rolling has led to the widespread use of continuous mills with a retained mandrel and 3-roll gauges for rolling hollow billets. Consequently, this required the updating of a number of theoretical positions related to changes in kinematics of the process. In the rolling process on a continuous rolling mill, the rolls and the mandrel are operated under difficult temperature conditions and constant cyclic alternating loads; as a result, they are subjected to considerable wear. Therefore, when force values reach critical ones, rolling contributes to emergency situations caused, in particular, by the destruction of the material of working tools (rolls, the mandrel). Moreover, the stated circumstances are mostly found in the first mill stands, where the pipe material is subjected to great reductions. Due to the fact that the deformation during pipe rolling on a continuous mill is distributed among 5-6 stands, this additionally imposes certain limitations and reduces the possibility of varying the rolling process parameters in a wider range. In this regard, there is a need to develop and adapt mathematical models for calculating, predicting, and selecting an optimal rolling schedule depending on the product mix of a continuous tube rolling mill. As part of this study, a method for determining the energy parameters of the process has been developed on the basis of the energy theory. When preparing the equilibrium equation for the projections of forces on the longitudinal axis, the authors determined average values of pressure at the contact with work rolls and the mandrel. The developed mathematical models and the algorithm for calculating the energy parameters of the process of rolling hollow billets on a continuous mill made it possible to determine with a sufficiently high accuracy rolling force on a continuous tube rolling mill. The dependencies found can be used both for research purposes and the calculation of rolling tables on tube rolling machines with continuous rolling mills.