Shramko A. Basis and development of rational production process of higher quality railway wheels in consideration of its history of deformation

Thesis is devoted to development of scientific fundamentals of hot plastic deformation of steel during multistage forging and development of rational modes of deformation in view with complex influence of deformation parameters including history of deformation. Herein improved method of calculation of plastic deformation processes during multistage forging and rolling of railway wheels due to consideration of physical and technological peculiarities of this process such as change of temperature, cumulative deformation, interdeformational pauses, rheological properties and density of wheel steel, form of billet and tool as well as contact friction. It is shown that increased nature of metal deformation rate in central zone of wheel rim up to maximum values on the final run and monotone decreased nature of deformation distribution though runs contribute to increase ductile and plastic characteristics retaining high level of strength. Firstly, experimental data of energy-power parameters during forging ofrailway wheels with different process flowsheets in wheel rolling shop environment are obtained. Method of calculation of position of neutral surface of metal flow during multistage forging using finite element analysis improved. Rational production process of railway wheels with 957 mm diameter according to ГОСТ 10791-2004 and production process of higher quality railway wheels with 1098 mm diameter according to IRS R-19/93 developed and approved for implementation at JSC "NTRP". Key words: railway wheels, hot deformation, multistage forging, deformational and energy-power parameters, history of deformation, mechanical properties.