Analysis of the Influence of the Degree of Strainon the Accuracy of Predicting the Rolling Force of Rods

The process of rolling in gauges, in contrast to the rolling of flat products in cylindrical rolls, is characterized by significant non-uniformity of deformation.This causes certain complications in determining generally accepted parameters that characterize the rolling process. One of these parameters is the degree of strain per pass, the method of determining which can significantly affect the most significant rolling parameters. Therefore, the study of the influence of the degree of strain on the accuracy of forecasting the rolling force in gauges is quite relevant and has significant practical significance. The aim of the work is to analyze the scale of influence of the degree of strain on the rolling parameters and to determine the most acceptable parameter for calculating the rolling force of rods. For conditions known from the literature for rolling rods with a diameter of 8 mm in the "oval - round" system of pass,the degree of strainparameter was determined in four different ways. For further analysis, the averaged degree of strain, as two-thirds of the reduction ratio per pass, and the degree of strain determined by the relative change in area were selected. For such indicators, calculations of intermediate parameters and rolling force were performed using various methods. Calculations of the stress state coefficient were performed using the techniques of Lee and Smirnov. The average metal yield stress, or resistance to deformation, was determined according to the methods of Dinnyk, Misaka, and Andreyuk. Determination of the most acceptable indicator of the degree of strain per pass was carried out according to the level of accuracy of the rolling force calculations, comparing them with experimental force values. It was established that the averaged reduction ratio, determined by the dimensions of the equivalent stock, provides the highest accuracy of force prediction among the possible indicators of the degree of strain per pass. For this indicator of the degree of strain, the Smirnov-Andreiuk and Lee-Misaka methods provide the highest accuracy of predicting the rolling force. For practical use, the Lee-Misaka method can be recommended, which provides an acceptable average error and a relatively small maximum error relative to the used experimental data on the rolling force.