This paper is concerned with identification of the mathematical model of the chip forms in turning, which is represented in terms of chemical composition and mechanical properties, by applying the polynomial theory on the basis of heuristic self-organization (GMDH), used for the identification and the prediction of the complex systems in which a number of variables and parameters exist. According to the method, the accurate model is not only identified, but the factors affecting the outputs directly are chosen, with a small number of input and output data. Through the identification of the model, carbon, sulphur, reduction of area and Brinell hardness are selected as independent variables from among the factors considered to have an effect on the chip forms. From the established model, it was found that, the carbon and Brinell hardness have great influence on the chip forms, while the sulphur has little influence on them.