20th issue of the journal "KB"

Abstract. The article discusses a method for calculating the strength of the roll collars for section mills, based on known formulas for the resistance of materials. The use of this technique, in contrast to the choice of recommended collar widths, which is common in practice and proposed in the literature, makes it possible to determine the minimum allowable collar width with the condition of maintaining its strength. The scope of calculations, in contrast to the finite element method, makes it possible to determine the width of the shoulder immediately at the design stage, taking into account the variation of the entire complex of roll pass design parameters. On the example of the calibration of a 30P channel used on a rail and beam mill, the calculation of the allowable width of the strength of the collars for each pass was made. According to the results obtained, the allowable width of the collars is not directly proportional to the depth of the groove, as is simply accepted in practice. The analysis of the results of calculations and practical data on the destruction of collars was carried out. The application of the developed technique makes it possible to more rationally use the working space of the roll.
Keywords: collar strength condition, rolling roll, calibre, groove, channel pass design.

Abstract. In this paper, based on study results of four 76HF rail steel experimental batch, influence of micro-alloying elements V and Nb, as well as hot deformation and heat treatment on decay kinetics of austenite rail steel is presented. The individual and complex influence of the content of micro-alloying elements in steel on the formation of the thermokinetic diagram of austenite decay is determined, and the most favorable scheme of thermomechanical processing is determined.
Keywords: 76HF rail steel, differentiated hardening, thermomechanical treatment, thermokinetic diagram of supercooled austenite, microalloying, vanadium, niobium.

Abstract. The article presents the results of calculations for the calibration of ball rolling rolls with three-start screw calibres with a displaced center of the streams for rolling steel grinding balls with a diameter of 50 mm according to GOST 7524-2015. Key words: grinding balls, screw calibre, ball-rolling roll, flange, cam copier, MathCAD 15.

Abstract. At the EVRAZ NTMK JSC in rail and beams rolling shop in 2018 years, was building ball rolling mill with high definition of automation. Product tracking system of the metals route in the ball rolling mill at rail and beam shop is devoted in this paper. System see all parameters on technologic process in all time, and all off-spec balls, will not reach the customer, because the system won't enable is make. The mill automation system, made it possible to ensure maximum traceability of the metal, which not only greatly facilitates the work of the site employees, but also provides full feedback to consumers.
Keywords: grinding ball, ball rolling mill, automatic system, tracking of metal movement, process parameters, quenching.