Estimation of the influence of various factors on the quality of hot-rolled pipes

The article considers major factors affecting the quality of hot rolled pipes, namely, the accuracy of geometric dimensions of pipes. Two main parameters affecting the longitudinal curvature of pipes are distinguished. Numerical estimations of the influence of diameter differences of a roll barrel-roll mill and the displacement of one roll along the axis of the rolling pipe curvature were carried out. For this purpose simulation of pipe rolling in one two-roll mill with the roll calibration corresponding to the calibration of the previous extractor mill was carried out. Simulation was carried out with different diameter sizes of the barrel of one roll and different displacement values of one roll along the rolling axis. These factors had a significant influence on the curvature which was shown by the analysis of the model tube geometry after rolling. Processing of the simulation results and data allowed to receive deviation dependences on the pipe linearity and the difference between roll barrels diameters. In addition, the deviation dependence on the displacement between straight pipes and one roll along the rolling axis was determined. Formulas and dependences received in this study can be further used in setting up a pipe mill and will greatly improve the production quality. A peculiar feature of this research in determining the influence of various factors on pipe curvature at its deformation is that the impact assessment was carried out by means of simulation using the finite element method. The research is not complete and will be further supplemented by the assessment results of the deviation impact from linearity on account of the condition of the pipe grip by the next pipe rolls of the stand extractor mill.