One of the important tasks for domestic mechanical engineering in the field of manufacturing is the prediction of the temperature regime in the zone of interaction between the tool and the workpiece during the processing of various ferrous metal products. In the context of modeling most calculation procedures related to the machining process, there are problems with determining the objective function describing the specific conditions of interaction between the tool and the workpiece. The aim of the work is an experimental study of the dependence of the temperature in the cutting zone of cast-iron workpieces SCH-15 on the coating materials that are applied to the metal-cutting tool and obtaining empirical objective functions based on it that adequately describe this processing process. During the implementation of this algorithm in the laboratory, based on a priori information, the research area was selected and the limiting levels of factors with varying intervals in this area were established. At the next step, a factorial experiment was performed and its results were processed on the basis of a linear polynomial, taking into account linear effects and the interaction effect. In the process of evaluating the polynomial, a confidence interval was determined for all regression coefficients from three parallel experiments with the same values of factors. At the second stage of its evaluation, the adequacy of the resulting mathematical model was checked according to the Fisher criterion. At the final stage, using the well-known logarithm mechanism, a transition was made from the encoded values of the factors in the resulting polynomial to their natural values. During the implementation of this algorithm, power functions describing the temperature conditions in the cutting zone during the processing of a cast-iron billet with a carbide tool material with coatings in the form of TiN, ZrN and ZrTiN were obtained. As a result of the study, it was found that the non-combined coating of carbide plates allows minimizing the temperature in the cutting zone when turning hard-to-process materials by an average of 10 % compared to the combined coating, which increases the productivity of the shaping process by this amount. This technique is the subject of consideration in this work.