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This study addresses the need to improve methods for calculating deformation parameters in cold pilger tube rolling mills, identify the most accurate calculation approaches, improve tube dimensional accuracy, optimize energy consumption, and extend the service life of the deformation tooling used in these mills. The aim of the study was to determine the distribution function of deformation parameters in the sizing zone and to carry out a comparative analysis of methods for calculating the deformation fractionation parameter. The study involved an analysis of six industrial groove-pass designs for an HPT-32 mill, whose tooling had been used to roll industrial batches of tubes. Two groovepass designs employing a mandrel with a curved working-profile generatrix and four designs using conical mandrels were selected. It was found that the deformation function in the sizing zone decays over the section corresponding to the linear displacement of the tube per pass. Over a substantial part of this section, the deformation magnitude was shown to be considerably smaller than the diameter tolerance, which is important for optimizing the length of the sizing zone. Analysis of the accuracy of determining the deformation fractionation parameter showed that the method based on the P.K. Teterin formula makes it possible to determine this parameter more accurately than the generally accepted formula most widely used in the literature. The greater the deviation of the groove-pass profile and the mandrel working zone from a conical shape, the larger the discrepancy, which may reach 25–30 %. It was established that the P.K. Teterin formula for calculating the deformation fractionation parameter takes into account the effect of changes in metal volume within the deformation cone, thereby allowing this value to be determined with improved accuracy. The results obtained make it possible to improve the accuracy of deformation-parameter calculations, which is important for optimizing cold tube rolling processes.