CONTROL OF ANNEALING OF STEEL COILS IN BELL FURNACE

Abstract

Introduction. The current problem of controlling the annealing of steel coils in bell-type furnaces is considered. Purpose of the study. Improving existing control systems and specifying a method for assessing the temperature of the extreme (coldest) point of setting at the holding stage. Materials and methods. An analysis of both literature data on the problem under consideration and the actual technology of heat treatment of steel coils in bell-type furnaces was carried out. The structure of the applied annealing process control systems is discussed, and preferred solutions are highlighted. Results. For electric re- sistance furnaces with two zone heaters (and, accordingly, with two zone thermocouples) and one bench thermocouple, a continuous type automatic control system (ACS) is recommended. Due to this, the accuracy of maintaining temperatures is increased, frequent thermal changes in furnace zones are eliminated, and over- heating of the bell and cage zones is prevented. A fairly simple way to increase the productivity of furnaces through the use of automatic program control systems is indicated. For the holding period, an adaptive mathe- matical model of the temperature field of the lower roll is proposed, which makes it possible to increase the accuracy of determining the moment of the end of the process. To set up the model, it is proposed to mea- sure the temperature at three different points along the radius of the bottom roll base during the current annealing. The issues of creating modern intelligent control systems are considered. Conclusion. The results of the work can be used in the construction of automated process control systems (APCS) for bell-type furnaces.