Induction system for heating large rings before rolling

Abstract

The paper considers the issues of designing an induction system for heating large-sized hollow cylindrical billets before rolling. The specific features of the billets heating process at the installation built into the technological processing line are noted. It is shown that for increasing the efficiency of the process of heating large-sized steel billets it is expedient to carry out the system of inductors with the use of a heat shield. A study of the process of heating of workpieces taking into account the nonlinear dependence of the physical characteristics of the metal of heated workpieces on the temperature changing in the process of heating is performed. The parameters of the induction system are calculated on the basis of a two-dimensional model. The geometric parameters of the circular billet resulted in a significant nonuniformity of the current density distribution along the axial coordinate of the billet due to the strongly pronounced boundary effects. The results of numerical calculation of the electromagnetic and thermal fields at different variations of the induction system design are presented. In order to substantiate and select the design of induction system that provides heating of the ring for the time caused by the work rate of the deforming equipment. A series of calculations was made, including three options: heating by an external cylindrical inductor; heating by two inductors: heating by inductor system with a heat shield. Analysis of efficiency of the investigated variants is based on multiple refinement of the results in the process of iterative design. Results of calculation of temperature distribution in the billet during heating are presented. The results of the research can be used to develop design and operating parameters of induction ring heating system in the rolling line.