Problem Statement (Relevance). The technology of producing hot-deformed tubes on tube rolling facilities with the rough tube elongation by longitudinal rolling on a short mandrel in the range of the nominal diameter/wall thickness ratio, D/S = 25-35, is characterized by containing longitudinal end defects. The transfer of tubes with these defects after the automatic mill (or the tandem mill) into the downstream mills is accompanied by an increase in the energy and power parameters of the processes, and, therefore, impact loads on the units of the stands and the drive of the mills. Objectives. The research is aimed at assessing loads that occur when flattening longitudinal end defects of tubes on burnishing mills using the mathematical simulation of the process to determine loads during the process and obtain the final forming shape for the tube after the burnishing stand depending on the process parameters. Methods Applied. For a 3D problem statement used to determine the stress and strain state of the tube material in the deformation zone, the DEFORM 3D modeling software suite is used based on the finite element method (FEM) for plastic flow problems. Originality. Development of a mathematical model of the tube burnishing process after an automatic rolling mill by helical rolling on a conical mandrel, factoring into geometry of the defective rear end of the tube formed during the elongation at the previous stage and the stress and strain state of the workpiece before burnishing, and varying the burnishing mode, perform simulation for various materials (including steels of higher strength groups). Result. The authors obtained novel data on the loads on the tool for all the process stages: from feeding the workpiece into an operating stand at the steady state, and to the exiting tube with the defective end between the rolls and the mandrel, leading to a peak increase in loads. Practical Relevance. The model can be used to obtain new data on the burnishing process.