Grygorenko V. Development of the theory, creation and reduction to practice of the new processes of continuous periodical roller cold rolling of especially thin-walled and multiply tubes

The scientific basis of processes of the cold continuous periodical roller rolling of especially thin-walled and multiply tubes was developed. The theoretical solutions concerning determination of the rational values of ideal diameters of rollers in the rows, parameters of profile of the roller pass design, development of the notion about the mechanism of decreasing the cross-sectional wall thickness deviation while reducing obtained the further development. For the first time were obtained the experimental data on the force interaction of the rollers rows while rolling with different values of the feed, distribution of deformations along the perimeter of the pass, change of the wall thickness of the tube along the perimeter of the latter depending on the ratio of the roll diameter to the tube diameter while reducing. The new effective processes of the two- and the three-row roller rolling with increased reduction and fractionness of deformation were created and reduced to practice as well as two-row process of rolling the multiply tubes in packs with decreased inhomogeneity of layers deformation. The improved designs of two-row stands of the cold roller tube rolling mills 6 - 15, 30 - 45, 30 - 60 were developed and reduced to practice as well as three-row stand of the cold roller tube rolling mill 8 - 15. The number of cycles of the working was shortened. Results of the work were reduced to practice in the Nikopolski South Tube Plant and used at the sale of technologies, tools and rolling stands on the license base for export. The economic efficiency makes up 80 thousand transaction rubles from the sale for export and more than 2 millions grn of the annual economic effect.