Vol. 25 No. 3 2023 3 EDITORIAL COUNCIL EDITORIAL BOARD EDITOR-IN-CHIEF: Anatoliy A. Bataev, D.Sc. (Engineering), Professor, Rector, Novosibirsk State Technical University, Novosibirsk, Russian Federation DEPUTIES EDITOR-IN-CHIEF: Vladimir V. Ivancivsky, D.Sc. (Engineering), Associate Professor, Department of Industrial Machinery Design, Novosibirsk State Technical University, Novosibirsk, Russian Federation Vadim Y. Skeeba, Ph.D. (Engineering), Associate Professor, Department of Industrial Machinery Design, Novosibirsk State Technical University, Novosibirsk, Russian Federation Editor of the English translation: Elena A. Lozhkina, Ph.D. (Engineering), Department of Material Science in Mechanical Engineering, Novosibirsk State Technical University, Novosibirsk, Russian Federation The journal is issued since 1999 Publication frequency – 4 numbers a year Data on the journal are published in «Ulrich's Periodical Directory» Journal “Obrabotka Metallov” (“Metal Working and Material Science”) has been Indexed in Clarivate Analytics Services. Novosibirsk State Technical University, Prospekt K. Marksa, 20, Novosibirsk, 630073, Russia Tel.: +7 (383) 346-17-75 http://journals.nstu.ru/obrabotka_metallov E-mail: metal_working@mail.ru; metal_working@corp.nstu.ru Journal “Obrabotka Metallov – Metal Working and Material Science” is indexed in the world's largest abstracting bibliographic and scientometric databases Web of Science and Scopus. Journal “Obrabotka Metallov” (“Metal Working & Material Science”) has entered into an electronic licensing relationship with EBSCO Publishing, the world's leading aggregator of full text journals, magazines and eBooks. The full text of JOURNAL can be found in the EBSCOhost™ databases.
OBRABOTKAMETALLOV Vol. 25 No. 3 2023 4 EDITORIAL COUNCIL EDITORIAL COUNCIL CHAIRMAN: Nikolai V. Pustovoy, D.Sc. (Engineering), Professor, President, Novosibirsk State Technical University, Novosibirsk, Russian Federation MEMBERS: The Federative Republic of Brazil: Alberto Moreira Jorge Junior, Dr.-Ing., Full Professor; Federal University of São Carlos, São Carlos The Federal Republic of Germany: Moniko Greif, Dr.-Ing., Professor, Hochschule RheinMain University of Applied Sciences, Russelsheim Florian Nürnberger, Dr.-Ing., Chief Engineer and Head of the Department “Technology of Materials”, Leibniz Universität Hannover, Garbsen; Thomas Hassel, Dr.-Ing., Head of Underwater Technology Center Hanover, Leibniz Universität Hannover, Garbsen The Spain: Andrey L. Chuvilin, Ph.D. (Physics and Mathematics), Ikerbasque Research Professor, Head of Electron Microscopy Laboratory “CIC nanoGUNE”, San Sebastian The Republic of Belarus: Fyodor I. Panteleenko, D.Sc. (Engineering), Professor, First Vice-Rector, Corresponding Member of National Academy of Sciences of Belarus, Belarusian National Technical University, Minsk The Ukraine: Sergiy V. Kovalevskyy, D.Sc. (Engineering), Professor, Vice Rector for Research and Academic Aff airs, Donbass State Engineering Academy, Kramatorsk The Russian Federation: Vladimir G. Atapin, D.Sc. (Engineering), Professor, Novosibirsk State Technical University, Novosibirsk; Victor P. Balkov, Deputy general director, Research and Development Tooling Institute “VNIIINSTRUMENT”, Moscow; Vladimir A. Bataev, D.Sc. (Engineering), Professor, Novosibirsk State Technical University, Novosibirsk; Vladimir G. Burov, D.Sc. (Engineering), Professor, Novosibirsk State Technical University, Novosibirsk; Aleksandr N. Korotkov, D.Sc. (Engineering), Professor, Kuzbass State Technical University, Kemerovo; Dmitry V. Lobanov, D.Sc. (Engineering), Associate Professor, I.N. Ulianov Chuvash State University, Cheboksary; Aleksey V. Makarov, D.Sc. (Engineering), Corresponding Member of RAS, Head of division, Head of laboratory (Laboratory of Mechanical Properties) M.N. Miheev Institute of Metal Physics, Russian Academy of Sciences (Ural Branch), Yekaterinburg; Aleksandr G. Ovcharenko, D.Sc. (Engineering), Professor, Biysk Technological Institute, Biysk; Yuriy N. Saraev, D.Sc. (Engineering), Professor, Institute of Strength Physics and Materials Science, Russian Academy of Sciences (Siberian Branch), Tomsk; Alexander S. Yanyushkin, D.Sc. (Engineering), Professor, I.N. Ulianov Chuvash State University, Cheboksary
Vol. 25 No. 3 2023 5 CONTENTS OBRABOTKAMETALLOV TECHNOLOGY Salikhyanov D.R., Michurov N.S. Simulation of the rolling process of a laminated composite AMg3/ D16/AMg3.......................................................................................................................................................... 6 Ilinykh A.S., Pikalov A.S., Miloradovich V.K., Galay M.S. Experimental studies of high-speed grinding rails modes.......................................................................................................................................................... 19 Salikhyanov D.R., Michurov N.S. The concept of microsimulation of processes of joining dissimilar materials by plastic deformation......................................................................................................................... 36 EQUIPMENT. INSTRUMENTS Tratiya D.K., Sheladiya M.V., Acharya G.D., Acharya S.G. Economical crankshaft design through topology analysis for C type gap frame power press SNX-320.......................................................................... 50 Skeeba V.Yu., Vakhrushev N.V., Titova K.A., Chernikov A.D. Rationalization of modes of HFC hardening of working surfaces of a plug in the conditions of hybrid processing................................................................ 63 MATERIAL SCIENCE Ruktuev A.A., Yurgin A.B., Shikalov V.S., Ukhina A.V., Chakin I.K., Domarov E.V., Dovzhenko G.D. Structure and properties of HEA-based coating reinforced with CrB particles.................................................. 87 Maytakov A.L., Grachev A.V., Popov A.M., Li S.R., Vetrova N.T., Plotnikov K.B. Study of energy dissipation and rigidity of welded joints obtained by pressure butt welding................................................... 104 Singh S.P., Hirwani C.K. Analysis of mechanical behavior and free vibration characteristics of treated Saccharum munja fi ber polymer composite...................................................................................................... 117 Pribytkov G.A., Baranovskiy A.V., Korzhova V.V., Firsina I.A., Krivopalov V.P. Synthesis of Ti–Fe intermetallic compounds from elemental powders mixtures.............................................................................. 126 Singh S.P., Hirwani C.K. Free vibration and mechanical behavior of treated woven jute polymer composite............................................................................................................................................................ 137 EDITORIALMATERIALS 152 FOUNDERS MATERIALS 163 CONTENTS
OBRABOTKAMETALLOV Vol. 25 No. 3 2023 technology Experimental studies of high-speed grinding rails modes Andrey Ilinykh 1, a, *, Aleksandr Pikalov 2, b, Vladimir Miloradovich 2, с, Marina Galay 1, d 1 Siberian Transport University, 191 Dusy Kovalchuk st., Novosibirsk, 630049, Russian Federation 2 Moscow Center for Infrastructure Technologies JSC “STM”, 4B Podkopaevsky pereulok, 109028, Russian Federation a https://orcid.org/0000-0002-4234-6216, asi@stu.ru, b https://orcid.org/0000-0002-9584-9896, pikalov.2023@internet.ru, c https://orcid.org/0000-0002-8258-5801 , vmiloradovich@internet.ru, https://orcid.org/0000-0002-7897-1750, galayms@mail.ru. Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2023 vol. 25 no. 3 pp. 19–35 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2023-25.3-19-35 ART I CLE I NFO Article history: Received: 17 May 2023 Revised: 29 May 2023 Accepted: 16 June 2023 Available online: 15 September 2023 Keywords: Rail grinding Abrasive processing Grinding modes Railway track Funding The research was carried out with the financial support of subsidies from the Federal Budget for the development of cooperation between Russian educational institutions of higher education, state scientific institutions and organizations of the real sector of the economy in order to implement complex projects to create high-tech industries. The financial support is stipulated by the Decree of the Government of the Russian Federation of April 9, 2010 No. 218 on the topic “High-performance technology for highspeed rail grinding and equipment for its implementation based on intelligent digital modules”, agreement No. 075-112022-014 of April 08, 2022. Acknowledgements Research was partially conducted at core facility “Structure, mechanical and physical properties of materials”. ABSTRACT Introduction. Rails’ grinding in the conditions of a railway track is a priority for extending its life cycle due to the timely removal of tread surface defects and formation of required transverse profile. Today, 14 RSHP-48 rail grinding trains are used in Russia. At the same time, most rail grinding trains are ending its service life. Therefore, the development of a fundamentally new rail grinding train with increased efficiency is an urgent task. Siberian transport university is working together with the Kaluga plant “Remputmash” to create a new rail grinding train named RSHP 2.0. The rail grinding train RSHP 2.0 is based on the technology of high-speed rail grinding, which is based on increasing working speed of rail grinding train by increasing rotational speed of grinding wheels and setting the angle of attack. The aim of this work is to study rails’ grinding modes on a specially designed installation URSH, which implements the technology of high-speed grinding rails by increasing speed of grinding wheels rotation up to 5,000 rpm. Research methods. Grinding wheel speed control was carried out by IT-5-ChM “Termit” electronic tachometer and “Megeon 18005” laser tachometer. The angle of attack of grinding wheel was measured by digital, three-axis accelerometer-inclinometer ATst 90. The force of pressing grinding wheel to the rail was evaluated by strain-resistive sensors M500.5-C3. The measurement of head rail transverse profile before and after grinding and evaluation of metal removal were carried out by a PR-03 rail profiler. The width of grinding track was controlled by ShTsTs-I-300-0.01 caliper. The surface roughness of rail sample after machining was measured by TR 200 portable instrument. Results and discussion. Based on research results of CRS, the parameters of the working equipment of designed grinding rail train, which implements the technology of highspeed rail grinding, the influence of grinding modes on the formation of the quality parameters of the machined rail surface are established, and the optimal values of the forces of pressing the grinding wheel to the rail are determined. For citation: Ilinykh A.S., Pikalov A.S., Miloradovich V.K., Galay M.S. Experimental studies of high-speed grinding rails modes. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2023, vol. 25, no. 3, pp. 19–35. DOI: 10.17212/1994-6309-2023-25.3-19-35. (In Russian). ______ * Corresponding author Ilinykh Andrey S, D.Sc. (Engineering), Professor Siberian Transport University, 191 Dusy Kovalchuk st., 630049, Novosibirsk, Russian Federation Tel.: +7 (383) 328-03-92, e-mail: asi@stu.ru
OBRABOTKAMETALLOV technology Vol. 25 No. 3 2023 Introduction The process of rails grinding has been actively used on the Russian railway network since the early 2,000s. The technology has proven itself to be the only one that allows extending the life cycle of the rail [1, 2]. This technology is implemented using rail grinding trains of the RSHP-48 type, which are a complete copy of the Swiss trains of the Speno company (RR modifications), developed in the 1,980s of the XX century [3]. The main functions of rails grinding (fig. 1a) are the creation of the necessary rail profile to ensure the best interaction of the wheel with the rail, as well as the removal of defects that are formed on the wheel thread [4, 5, 6]. To process a complex profile of rails, grinding is performed by tilting the grinding wheels at different angles (fig. 1b). a b Fig. 1. Schematic representation of rail grinding by a rail grinding train: a – a schematic representation of flat grinding of rails with the end of the wheel; b – the inclination of the grinding heads when processing the rails’ profile It should be mentioned that the rail grinding trains, which are operated on the railway network, have speed limits up to 8 km/h and the speed of grinding wheels up to 3,600 rpm [3]. With such parameters, rail grinding trains have low efficiency, which makes it necessary to close the runways for movement during the work on grinding rails, which leads to significant financial losses [7]. Thus, the issue of increasing the efficiency of rail grinding trains is extremely relevant for the development of the railway industry. In total, 21 rail grinding trains have been manufactured in Russia for all time. Starting from 2,021, due to the technical condition of the machines and the end of its service life, the retirement of rail grinding trains from operation began. At the end of 2,022, there were 14 RSHP-48 trains operating on the Russian railway network, which, in the context of its low efficiency, do not meet the needs of railways in rails grinding. In view of the foregoing, the Sinara-Transport Machines Holding, which is the only supplier of rail grinding services for the Russian Railways company, decided in 2,021 to create a fundamentally new machine – the Rail Grinding Train RSHP 2.0 (fig. 2). Fig. 2. Rail grinding train RSHP 2.0
OBRABOTKAMETALLOV Vol. 25 No. 3 2023 technology The operation of the new train is based on the technology of high-speed grinding of rails, which was developed at the STU in the late 2,000s [8] and underwent preliminary industrial testing [9]. The new technology was proposed based on the theory of cutting during abrasive processing [10–12], wherein an increase in the working speed of a rail-grinding train is impossible without a proportional increase in the speed of rotation of the grinding wheel. Otherwise, an increase in feed can lead to a significant deterioration in the quality parameters of the processed surface and a decrease in metal removal. Increased wear of the abrasive tool is also possible due to a violation of the optimal modes of its operation [13]. Thus, the following conditions were implemented in the high-speed grinding technology: 1) the first condition is that the abrasive wheel is located at an angle α to the surface of the rail being processed with the opening towards the rail grinding train movement direction (“angle of attack”). Due to this arrangement of the grinding wheel, a uniform allowance is achieved between the abrasive grains, while reducing the wear of the abrasive tool (fig. 3). The highest efficiency in the grinding of rails is achieved with the correct selection of angle α, since its value depends on the metal removal. The angle α is taken with provision for the size of the grinding wheel and the average value of the expected metal removal, and is 0.35 degrees in accordance with the calculations according to the equation: 0,3 sin 0.006, ( ) / 2 (250 150) / 2 t D d α= = = - - where t is the expected metal removal, mm (t = 0.3 mm); D is the outer diameter of the grinding wheel, mm (D = 250 mm); d is the inner diameter of the grinding wheel, mm (d = 150 mm). 2) the second condition is to increase the rotation speed of the grinding wheel. An increase in the rotation speed leads to an increase in the metal removal rate, while the cutting force decreases, at the same cutting depth. It has been previously established that increasing the rotation speed of the grinding wheel to 5,000 rpm will increase the working speed of the rail grinding train to 15 km/h without reducing metal removal [9]. The practical application of the adopted technological solutions requires the development of grinding modes, which should form the basis for the design of new working equipment for a rail grinding train. Setting research objectives Currently, the Kaluga Remputmash, together with the Siberian Transport University, is conducting design work on a new rail grinding train. Within the framework of the technical project, the corresponding characteristics of all control systems for the rail grinding process are laid down, which depend on the implemented operating modes of the rail grinding train. The operation of rail grinding trains is characterized by fundamental differences from grinding on machines in stationary conditions [14]. Grinding of rails is carried out due to the force closure of the kinematic pair “abrasive wheel – surface being processed” (fig. 4). Each individual grinding wheel is pressed against the rail head by a pneumatic cylinder through a drive motor mounted on a motor plate. The axes of rotation of the parallelogram suspension are fixed on the end plate of the block of the grinding trolley. This design ensures a constant perpendicularity to the axis of rotation of the circle relative to the longitudinal axis of the rail. Fig. 3. Schematic representation of interaction of an abrasive tool with a rail during high-speed grinding
OBRABOTKAMETALLOV technology Vol. 25 No. 3 2023 In this case, the force of pressing the grinding wheel to the rail is determined by the pressure in the pneumatic cylinder, which is automatically adjusted depending on the current load on the windings of the electric motor in accordance with the schematic pattern shown in fig. 5. The specified feature of the rail grinding process does not allow implementing the cutting depth accurately, since metal removal will occur spontaneously depending on a number of factors, and with a high probability will differ from the specified value. Accordingly, the rail profile forming accuracy will Fig. 4. Grinding head attachment pattern: 1 – abrasive wheel; 2 – electric motor; 3 – under-engine plate; 4 – parallelogram suspension; 5 – pneumatic cylinder; 6 – block plate; 7 – axis Fig. 5. The pressing force of grinding wheel common control circuit: 1 – grinding modes control unit; 2 – proportional valve; 3 – converter of the adjusting block; 4 – grinding block; 5 – pneumatic cylinder; 6 – grinding wheel drive motor
OBRABOTKAMETALLOV Vol. 25 No. 3 2023 technology be violated [15, 16], the working conditions of the abrasive tool [17, 18] and the formation of the quality of the treated surface will be changed. In order to minimize deviations of the actual metal removal from the specified (assumed) one, for which the appropriate cutting speed and feed are specified, it is required to obtain empirical dependencies of the entire technological system, which will allow further design of technological processes for grinding rails for various conditions. In view of the foregoing, the main purpose of the research was determination of the optimal modes of rails grinding in the implementation of high-speed grinding technology, providing maximum machining performance with the formation of the specified parameters of the quality of the rail head surface being processed and determination of the main parameters of the technological equipment RSHP 2.0 specific to these modes, such as pressure in the pneumatic system pressing the grinding wheel to the rail and the current load of grinding motors. To achieve this goal, the following tasks were solved: determination of the parameters of the pneumatic system, providing the required forces of pressing the grinding wheel to the rail; determination of the dependence of the current load in the windings of the electric motor on the force of pressing the grinding wheel to the rail; determination of the rated current load of the electric motor to the specified average values of the grinding wheel pressing force against the rail; assessment of metal removal and roughness of the processed surface in various grinding modes. Research methodology Currently, there are a number of test benches [19, 20] on which it is possible to implement research program tests of rail grinding technology. At the same time, it should be noted that all the installations available today are limited to the standard operating modes of existing rail grinding trains and do not allow it to be changed in a sufficiently wide range. In order to fulfill the tasks of studying the technology of rails high-speed grinding, a special rail grinding unit – URSH – was developed and manufactured. The URSH consists of a separate section of track with a length of 100 m, a standard gauge of 1,520 mm (fig. 6a), on which a rail grinding trolley moves (fig. 6b). The trolley is driven by a winch-type drive containing a motor, a transmission (clutch, brake, single-stage gearbox) and a drum with a single-layer winding (fig. 6b). As an energy source, a diesel generator set (hereinafter referred to as a DGS) with a capacity of 200 kW is used (fig. 6d). The operation of the URSH in test mode is automatic, controlled by a control system from a personal computer. Standard rails P50, P65, P75 are used for grinding, which are installed along the axis of the track. In this case, the level of the head of the working rail (test sample) coincides with the level of the rail head of the standard track. The rail is fixed on special brackets, with the possibility of its quick change and the ability to install a working rail with imitation of various defects of the real path. Fig. 7 shows a diagram of the attachment point of the working rail to the standard track. The rail grinding trolley is a non-self-propelled structure on wheels (fig. 8a), for moving along a standard gauge rail track. The trolley consists of a main frame, a frame of transverse displacement, a frame of transverse inclination. A mobile compressor station is located on the main frame to power the pneumatic cylinder pressing the grinding wheel to the working rail. A grinding head control system is implemented on the grinding trolley as on a rail grinding train, in accordance with the patterns in figs. 4–5 (fig. 8b). A transverse tilt frame with a mechanism mounted on it allows for the possibility of tilting the frame of the grinding unit (electric motor with a circle) in the range from +70° to -20° in accordance with the pattern (fig. 1b). The tilt is carried out using a stepper motor and a screw-nut transmission, the accuracy of setting the required angle is ± 0.5°, which is provided by the kinematics of the transmission itself.
OBRABOTKAMETALLOV technology Vol. 25 No. 3 2023 Fig. 7. Mounting unit of the working rail: 1 – rail for moving the sanding trolley; 2 – sleeper; 3 – test sample (working rail); 4 – spacer; 5 – lining; 6 – mounting studs; 7 – nut Fig. 6. General view of the URSH: a – section of the railway track; b – rail grinding trolley; c – drive; d – DGS а b c d As the drive of the grinding wheel, a standard RSHP electric motor is used, upgraded to be able to realize the shaft rotation speed of 5,000 min-1 with the torque on the shaft of the electric motor necessary to ensure the operation of the grinding wheel. The modernization was as follows: 1) increasing the nominal rotation speed of rolling bearings from 4,000 min-1 to 6,700 min-1 by replacing the rolling bearing brand; 2) changing the stator winding circuit from Δ (440 V, 60 Hz) to Υ (380 V, 50 Hz) for connecting the stator windings to Δ to provide increased power on the motor shaft. The actual, calculated technical characteristics of the modernized grinding motors are presented in Table 1. The frame of the grinding block is mounted on axle in a movable frame of transverse displacement. A lever mechanism with a pneumatic drive is located in the frame, which provides pressing of the grinding wheel with the required force up to 3 kN. Also, this mechanism allows setting the angle of attack of the grinding wheel equal to 0.35°.
OBRABOTKAMETALLOV Vol. 25 No. 3 2023 technology а b Fig. 8. Rail grinding trolley device: a – grinding trolley with transverse displacement frame; b – a grinding cradle with an installed grinding head and the possibility of transverse inclination Ta b l e 1 Technical characteristics of modernized electric motors Switching scheme Mode Current frequency, Hz Voltage, V Current, A Rotation speed, min–1 Shaft torque, N·m Power, kW D Idling 85 254 24 5100 0 0 Nominal mode 85 254 45 5029 49.8 26.2 Increase of the torque by 1.15 times from the nominal 85 254 56 5019 57.3 30.1 Increase of the torque by 1.5 times from the nominal 85 254 66 4994 74.7 39.1 Increase of the torque by 1.63 times from the nominal 85 254 70 4985 81.2 42.4 Increase of the torque by 2 times from the nominal 85 254 80 4958 99.6 51.7 Pressing the grinding wheel to the rail surface being processed is carried out on the basis of the pressure difference in the rod and piston cavities of the pneumatic cylinder. Pressure adjustment in the cavities of the pneumatic cylinder is carried out by a proportional pressure regulator based on data on the current load in the windings of the grinding motor. In accordance with the previously established characteristics of the technological process of high-speed grinding of rails, the URSH has the following technical characteristics: – the range of rotation speed of the grinding wheel is 3,600–5,000 rpm; – the range of change in the trolley movement speed is 4–30 km/h; – the range of the angle of inclination of the grinding motor from + 20° to - 60° from the vertical; – the angle of attack of the grinding wheel is 0.35° and is provided with the opening to meet the working movement of the trolley; – the range of change in the pressing force of the grinding wheel to the rail is 0–5 kN without taking into account the mass of the grinding motor.
OBRABOTKAMETALLOV technology Vol. 25 No. 3 2023 URSH is equipped with a special device for the pressing force calibration (fig. 9). The device allows determining the actual force of pressing the grinding wheel to the rail (in Newtons) depending on the current load in the windings of the electric motor. This dependence is further used to determine the actual cutting forces during operation based on the values of the current loads of the electric motor. The force of pressing the grinding wheel to the rail is measured by means of two force sensors. a b Fig. 9. Device for calibrating the pressing force of grinding wheel to rail: a – 3D-model of the device; b – general view of the device Taking into account the requirements for high-speed grinding wheels [21], research on the technology of high-speed rails grinding was carried out using grinding wheels “Machaon”, designed for a maximum grinding speed of 75 m/s (5,000 rpm). The tests were carried out with a grinding wheel angle of attack of 0.35°, at rotation speeds of 5,000 rpm. The roughness of the processed surface was estimated by the parameter Ra. During the research, the following measuring instruments were used: the control of the rotation speed of the grinding wheel during the grinding process was carried out by an electronic tachometer IT-5-FM “Termit” and a laser tachometer “Megeon 18005”; the installation of the transverse angles of inclination of the grinding motor and the angle of attack of the grinding wheel was carried out in accordance with measurements by a digital, three-axis accelerometer-inclinometer ATST 90, the pressing force was determined using a strain gauge sensor M50-0.5-S3, and the corresponding pressure in the pneumatic system was controlled using pressure converters ARIES PD100I-DI1,6-111-0,5; a rail profiler PR-03 was used to measure the transverse profile of the rail head before and after grinding and to assess the metal removal after processing; the width of the grinding track was monitored with a caliper SHCC-I-300-0.01; the surface roughness of the rail sample after processing was measured with a portable TR200 device. Results and its discussion Before conducting the research, the electric drive of the grinding head was adjusted, during which the dependence of the current load in the windings of the electric motor on the force of pressing the grinding wheel to the rail was established. The dependence of the power parameters on the pressure in the pneumatic system of pressing the grinding wheel to the rail was established to determine the parameters of the pneumatic system that provide the required force of pressing the grinding wheel to the rail and to assess its effect on the operating modes of the high-speed electric drive (fig. 10). It can be seen from the graph (fig. 10) that the greater the pressure in the pneumatic system, the greater the force pressing the grinding wheel to the rail. At the same time, it was found that the nominal pressing
OBRABOTKAMETALLOV Vol. 25 No. 3 2023 technology Fig. 10. Dependence of the pressing force of grinding wheel to rail on pressure in the pneumatic pressing system force is realized at a pressure in the pneumatic system up to 0.2 MPa, regardless of the rotation speed of the grinding wheel. According to the test results, the dependence of the change in the current load in the stator windings of the electric motor on the pressing force was obtained. Graphically, the dependence is shown in fig. 11. The graph shows that the change in the current load in the stator windings of the electric motor has a linear dependence on the forces arising during grinding. At the same time, it is established that for the tested electric drive, to ensure the design range of the rated current load of 45 A (Table 1), it is required to ensure the pressing force of the grinding wheel to the rail in the range of 2,500–2,800 N. The obtained dependences make it possible to adjust the force of pressing the grinding wheel to the rail and ensure the nominal operating modes of the high-speed grinding electric drive. Fig. 11. Dependence of current load change in the stator windings of the electric motor on the force of pressing the grinding wheel to rail
OBRABOTKAMETALLOV technology Vol. 25 No. 3 2023 To ensure the required modes of high-speed grinding of rails, the force of pressing can vary in the range 0.8–1.2 of the nominal value of the current load (45 A). That is, the technological modes of operation of the high-speed electric drive for current load range 37–53 A, which corresponds to the range of forces pressing the grinding wheel to the rail 2,200–3,100 N. The test results of the high-speed rail grinding technology are presented in Table 2. Graphically, the test results are presented in figs. 12–15. Ta b l e 2 Test results of high-speed rail grinding technology Passage No. The speed of the grinding trolley movement, km/h Speed of the grinding wheel rotation, min-1 Angle of transverse inclination of the grinding motor, degree The pressing force of the grinding wheel on the current load, A The actual pressing force of the grinding wheel, N Metal removal, mm Average metal removal, mm Roughness of the processed surface, µm The presence of cauterization (+/-) 1 10 5,000 -60 51 2,706 0.41 0,37 5.8 + 2 5,000 -40 51 2,704 0.4 5.4 + 3 5,000 -20 53 2,785 0.37 4.5 + 4 5,000 0 55 2,827 0.35 4.4 - 5 5,000 10 55 2,835 0.34 4.8 - 6 5,000 20 53 2,788 0.32 4.6 - 7 15 5,000 -60 51 2,712 0.49 0,28 6.2 + 8 5,000 -40 51 2,710 0.36 5.5 + 9 5,000 -20 53 2,786 0.25 4.6 - 10 5,000 0 55 2,832 0.19 3.2 - 11 5,000 10 55 2,836 0.21 3.8 - 12 5,000 20 53 2,790 0.20 4.8 - 13 20 5,000 -60 51 2,706 0.33 0,20 6.6 - 14 5,000 -40 51 2,704 0.28 5.8 - 15 5,000 -20 53 2,785 0.22 4.5 - 16 5,000 0 55 2,827 0.18 3.1 - 17 5,000 10 55 2,835 0.09 4.2 - 18 5,000 20 53 2,788 0.12 5.1 - 25 30 5,000 -60 51 2701 0.21 0,11 7.1 - 26 5,000 -40 51 2,698 0.19 5.7 - 27 5,000 -20 53 2,783 0.11 4.9 - 28 5,000 0 55 2,819 0.05 3.6 - 29 5,000 10 55 2,821 0.07 5.0 - 30 5,000 20 53 2785 0.03 5.3 -
OBRABOTKAMETALLOV Vol. 25 No. 3 2023 technology Fig. 12. Removal of metal at the angles of inclination of grinding motor It can be seen from the graph (fig. 12) that the maximum metal removal is achieved at the maximum angles of inclination of the grinding head, where the width of the grinding track is minimal. The effect of the longitudinal feed of the grinding wheel (the speed of movement of the grinding trolley) on the metal removal can be seen in fig. 13. With an increase in the longitudinal feed, the difference in the values of metal removal increases, which can be seen on the graph. For a grinding wheel rotation speed of 5,000 rpm, the speed of grinding trolley movement equal to 15 km/h is maximal, after which, with an increase in the longitudinal feed, a decrease in metal removal begins. Also it can be seen from the graph (fig. 13) that at 5,000 rpm, it is possible to achieve the target for metal removal of 0.2 mm at speeds of RSHP not exceeding 20 km/h. Approximating the data obtained by the average values of metal removal, we can make a conclusion about the possible modes of operation of the RSHP at high-speed grinding according to the performance criterion: 5,000 rpm – 15 km/h; 6,000 rpm – 20 km/h; 6,500 rpm – 25 km/h and 7,000 rpm – 30 km/h. Fig. 13. Dependence of metal removal on grinding modes
OBRABOTKAMETALLOV technology Vol. 25 No. 3 2023 These values are valid for nominal values of the grinding wheel pressing force for the range of current loads in the motor windings 37–53 A. In the future, when testing prototypes of industrial electric motors, these dependencies need to be clarified. Evaluation of the quality of the polished surface by the roughness parameter (fig. 14) showed that the nature of the curve is similar to the dependence of the metal removal at the angles of inclination of the grinding motor (fig. 12). This is natural because the greater the angle of inclination of the grinding motor, the smaller the width of the grinding track, and the specific load on a single grain is greater. As a consequence, the introduction of abrasive grains into the surface being processed is greater, which gives greater metal removal and, accordingly, surface roughness. The effect of the speed of grinding trolley movement on the formed surface roughness can be seen in the graph shown in fig. 15: with an increase in the working speed of movement, the surface roughness increases. This is also due to the influence of the number of abrasive grains passing through the elementary surface of the rail being processed. The higher the speed, the fewer such abrasive grains will be and, consequently, the roughness will be greater. In addition, it should be noted that in all ranges of grinding modes used in the tests, the roughness of the formed surface did not exceed the values established by the regulatory documentation for Ra – 6 µm. Fig. 14. Surface roughness at the angles of inclination of grinding motor Fig. 15. Dependence of roughness of the machined surface on grinding modes Also in the tests, the presence of cauterization on the polished surface was visually assessed. The passages after which the cauterization is fixed are marked with a “+” sign in the corresponding column of Table 3. According to the marked passages, it can be established that the occurrence of cauterization occurs when the maximum loads that occur during grinding are exceeded. This is typical for metal removal exceeding 0.35 mm. Conclusions According to the test results, the following parameters of the working equipment of the rail grinding train being designed, implementing the technology of high-speed rail grinding, are established: 1. The pneumatic system of the rail grinding train should implement a pressing pressure in the range of 0.8–1 atm per grinding head to ensure the necessary pressing force of the grinding wheel to the rail 2,800–2,900 N. 2. The range of current loads during operation of the electric drive of the grinding head is 37–53 A. Taking into account the long-term operation of the electric drive, the parameters of the diesel generator set,
OBRABOTKAMETALLOV Vol. 25 No. 3 2023 technology the cooling system of electric motors and the wiring should be designed for a maximum current load with a 1.5-fold factor, i.e. 80 A. 3. When manufacturing and testing an abrasive tool for the implementation of high-speed rail grinding technology, possible dynamic shock loads of up to 3,500 N. should be taken into account. Experimentally determined parameterswill make it possible tomake an appropriate choice of components for the control systems of the rail grinding drive and working equipment. The results of research on the technology of high-speed grinding of rails allow us to draw the following conclusions: 1. The tests carried out confirmed the fulfillment of the requirements of the technical specification for the rail grinding train RSHP 2.0 in terms of efficiency. The average thickness of the rail metal layer removing in one pass at maximum grinding power should be: ● 0.3 mm at an operating speed of 10 km/h; ● 0.2 mm at the operating speed of the RSHP – 15 km/h. 2. The possible range of the formed roughness of the processed surface of the rails is determined depending on the grinding modes and the angle of inclination of the grinding head. The possible values of the formed roughness according to Ra are 3.1–5.9 µm, which meets the requirements of the regulatory documentation on the maintenance of rails. 3. The permissible values of grinding modes are determined, taking into account the exclusion of the occurrence of cauterization on the processed surface of the rail. The presence of cauterization is typical when removing metal with a thickness of more than 0.35 mm, at speeds of movement of the grinding trolley up to 15 km/h. References 1. Fan W., Liu Y., Li J. Development status and prospect of rail grinding technology for high speed railway. Journal of Mechanical Engineering, 2018, vol. 54, iss. 22, pp. 184–193. DOI: 10.3901/JME.2018.22.184. 2. Schoch W. Grinding of rails on high-speed railway lines: a matter of great importance. Rail Engineering International, 2007, vol. 36, iss. 1, pp. 6–8. 3. Funke H. Rail grinding. Berlin, Transpress, 1986. 153 p. 4. Cuervo P., Santa J., ToroA. Correlations between wear mechanisms and rail grinding operations in a commercial railroad. Tribology International, 2015, vol. 2, pp. 265–273. DOI: 10.1016/j.triboint.2014.06.025. 5. Krishna V., Hossein-Nia S., Casanueva C., Stichel S. Long term rail surface damage considering maintenance interventions. Wear, 2020, vol. 460–461, p. 203462. DOI: 10.1016/j.wear.2020.203462. 6. Ding J., Lewis R., Beagles A., Wang J. Application of grinding to reduce rail side wear in straight track. Wear, 2018, vol. 402–403, p. 71–79. DOI: 10.1016/j.wear.2018.02.001. 7. Ilinykh A., Matafonov A., Yurkova E. Efficiency of the production process of grinding rails on the basis of optimizing the periodicity of works. Advances in Intelligent Systems and Computing, 2019, vol. 1116, pp. 672–681. DOI: 10.1007/978-3-030-37919-3_67. 8. Ilyinykh A.S. Skorostnoe shlifovanie rel’sov v puti [Speed rail grinding]. Mir transporta = World of Transport and Transportation, 2011, no. 3, pp. 56–61. 9. Ilinykh A.S., Pikalov A.S., Galay M.S., Miloradovich V.K. Povyshenie proizvoditel’nosti rel’soshlifoval’nykh poezdov metodom skorostnogo shlifovaniya [Increasing the performance of rail grinding trains by the method of speed grinding]. Izvestiya vysshikh uchebnykh zavedenii. Severo-Kavkazskii region. Tekhnicheskie nauki = University News. North-Caucasian Region. Technical Sciences Series, 2022, no. 4 (216), pp. 46–56. DOI: 10.17213/15603644202244656. 10. Doman D., Warkentin A., Bauer R. A survey of recent grinding wheel topography models. International Journal of Machine Tools &Manufacture, 2006, vol. 46, iss. 3, pp. 343–352. DOI: 10.1016/j.ijmachtools.2005.05.013. 11. ZengaW., Lib Z., Peib Z., Treadwell C. Experimental observation of tool wear in rotary ultrasonic machining of advanced ceramics. International Journal of Machine Tools & Manufacture, 2005, vol. 45, iss. 12–13, pp. 1468–1473. 12. JeongW., Shin J. Grinding effect analysis according to control variables of compact rail surface grindingmachine. Journal of the Korean Society for Railway, 2020, vol. 23, iss. 7, pp. 688–695. DOI: 10.7782/JKSR.2020.23.7.688. 13. Koshin A.A., Chaplygin B.A., Isakov D.V. Adequacy of the operating conditions of abrasive grains. Russian Engineering Research, 2011, vol. 31, no. 12, pp. 1221–1226. 14. AksenovV.A., IlinykhA.S., GalayM.S. MatafonovA.V. Osobennosti formirovaniya tekhnologicheskogo protsessa ploskogo shlifovaniya tortsom kruga pri uprugoi podveske shlifoval’noi golovki [Features of formation of the flat grinding
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