The development of automation and microcontroller equipment allows software implementation and industrial application of adaptive and optimal control systems. The issue of tuning the PI controllers of the zones of a furnace for heating steel before rolling at the Oskol Electrometallurgical Plant is resolved. The tuning of the PI controllers is described, and the choice of an adaptive control system based on a switching table is justified. The adaptive system allows improving the quality of control and keeping the temperature within the required operating range.