Copyright © 2022 M.M. Poberezhnyi, P.V. Kaplun, S.O. Kolenov. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Problems of Tribology, V. 27, No 1/103-2022,76-81 Problems of Tribology Website: http://tribology.khnu.km.ua/index.php/ProbTrib E-mail: tribosenator@gmail.com DOI: https://doi.org/10.31891/2079-1372-2022-103-1-76-81 Study of the kinetics of wear of steels from the point of view of the provisions of the adhesive-hydrodynamic theory of wear M.M. Poberezhnyi1*, P.V. Kaplun1, S.O. Kolenov 2 1Khmelnytskyi National University, Ukraine 2 Taras Shevchenko National University of Kyiv, Ukraine *E-mail: antanta2015@gmail.com Received: 20 February 2022: Revised: 30 February 2022: Accept: 26 March 2022 Abstract The article is devoted to the study of wear resistance of the surface layer of steels 40X and ШX15, when rubbed in oil I-20. A comparison of the surface layer of samples of raw and nitrided steels, before and after the tests. The study of the fine microstructure of the samples with the help of the LDFP microscope, allowed us to conclude that the samples that were subjected to ionic nitriding, improved roughness. In turn, increased the area of linear contact, reduced contact load. The graphic dependence of roughness indicators is constructed. After testing, we can conclude that nitrided steel has a long service life, namely high hardness, resistance to abrasion, durability and corrosion resistance. The mechanism for obtaining increased resources needs further study. Key words: test, operation, friction, 40X, ШX15, ionic nitriding, sample, roughness, I-20 Purpose Study of the kinetics of wear of steels from the point of view of the provisions of the adhesive- hydrodynamic theory of wear Introduction Quantitative comparison of performance characteristics of raw and nitrided steels. The studies were carried out with samples of 40Х and ШХ15 steels. Rolling friction tests in I-20 oil were carried out for steels without and after heat treatment. The data are presented in tables. Table 1 The nature of wear and durability of samples of steel 40X without heat treatment and nitrided, when tested for rolling friction in oil I - 20. Test time, hour The number of cycles, N∙106 Load per ball 150 Н Raw steel Nitrided steel Wear U, µm Hardness H100, µm Wear U, µm Hardness H100, µm 0 0 0 5480 0 7460 10 5.4 5 − 6 5720 4 − 5 7500 25 13.5 − − − − 50 27 10 − 12 − 9 − 12 7460 75 40.5 15 − 20 5550 14 − 19 − 100 54 26 − 30 5520 22 − 25 7280 150 81 − − − − 200 108 40 − 45 5430 30 − 32 7100 http://creativecommons.org/licenses/by/3.0/ http://creativecommons.org/licenses/by/3.0/ http://tribology.khnu.km.ua/index.php/ProbTrib https://doi.org/10.31891/2079-1372-2022-103-1-76-81 mailto:antanta2015@gmail.com Problems of Tribology 77 Continuation of Table 1 250 135 − − − − 300 162 55 − 60 5420 58 − 65 6840 350 189 370 hours U = 58–62 µm, N∙106 = 199.8, H100= 5520 − 400 216 65 − 70 6550 450 243 − − 500 270 70 − 75 5850 550 297 − − 600 324 75 − 80 5400 650 351 − − 700 378 80−85 4850 The rest Table 2 Physical, mechanical and tribological characteristics of samples with different coatings and their durability during rolling friction tests in oil I-20. Sample number Steel grade Type of heat treatment Surface hardness Load per ball 150 Н Test time, min Wear U, µm The number of cycles, N·106 1 ШХ 15 Without heat treatment Н100 3340 80 46 0.7 2 ШХ 15 Tempered HRC 60–61 – – – 3 ШХ 15 Tempered + nitrided Н100= 5880 60 18 0.54 Load per ball 300 Н 1 ШХ 15 Without heat treatment Н100 3340 – – – 2 ШХ 15 Tempered HRC 60–61 46 14 25.1 3 ШХ 15 Tempered + nitrided Н100= 5880 34 38 18.4 Friction track of a sample made of 40X steel without heat treatment 12 hours of work Friction track of a sample made of 40X steel, tempered and nitrided 183 hours of work Fig. 1. Comparison of the friction paths of 40X steel samples without heat treatment and after nitriding, during friction in I-20 oil. 78 Problems of Tribology The studies of rolling friction in oil I-20 made it possible to determine the characteristics of strength, ductility and wear resistance of samples of steels 40Х and ШХ15. The studies were carried out on samples without heat treatment, tempered and subjected to ion nitriding. The studies were carried out using a setup for testing contact endurance and wear resistance at linear contact. After the tests, it can be concluded that nitrided steel has a longer service life, namely, high hardness, resistance to seizure, endurance and corrosion resistance. Study of the fine microstructure of samples using a LDFP microscope Most carbon non-polar materials, when wetting the surfaces of machine parts, form epitropic liquid crystal structures on them in the nano- and micrometer range. Since their structure and properties are largely determined by the roughness of the working surface, it is necessary to have the most complete information about the three-dimensional state of the original surface. The nano-geometric surface of the samples needs appropriate control, which must be carried out by a non-contact method with high profile sensitivity and a sufficiently large field of view. Contact profilographs-profilometers of the Caliber M201 or M-283 type do not meet these requirements due to surface damage and low information content. Therefore, a laser scanning non-contact differential-phase microscope-profilograph-profilometer (LSDPMP) was used for the study. It was experimentally established that it is the 3D state of the working surfaces that characterizes their tribological properties, and not the roughness parameters (Ra, Rz, Rmax, Sm, tp, etc. ), calculated only from the profilogram. It has been experimentally established that for the same roughness parameter, in particular Ra, created by different technological methods, the surfaces have fundamentally different tribological properties depending on their 3D state. In addition to roughness, the microscope allows you to determine the volume of worn material in cubic nanometers, which significantly increases the accuracy of determining the amount of wear. Fig. 2. Graph of displaying the dependence of the values of the roughness parameters on the azimuth angle in the XY plane On the graph, the red line shows the angular dependence of the average value of the selected roughness parameter, and the blue lines show the boundaries of the deviation of this parameter from its average value within the studied area of the surface. Results After testing the wear resistance during rolling friction in I-20 oil, the surface of the samples was examined using an LDFP microscope, the results are presented in tables 3, 4. Problems of Tribology 79 Table 3 Parameters of the investigated roughness along the raceway. No Steel grade Type of heat treatment Roughness parameters, microns Ra Rz Rmax Rv Rp Rpk Sm 1 40Х Without heat treatment, raw 0.125 0.525 0.694 0.346 0.348 0.137 48.255 2 40Х Temper + nitrided 0.096 0.472 0.585 0.299 0.286 0.110 25.392 3 ШХ15 Temper + nitrided 0.074 0.356 0.443 0.214 0.229 0.087 27.188 Table 4 Parameters of the investigated roughness along the lateral surface No Steel grade Type of heat treatment Roughness parameters, microns Ra Rz Rmax Rv Rp Rpk Sm 1 40Х Without heat treatment, raw 0.161 0.652 0.855 0.410 0.445 0.187 48.078 2 40Х Temper + nitrided 0.036 0.177 0.217 0.113 0.103 0.038 27.596 3 ШХ15 Temper + nitrided 0.079 0.360 0.426 0.213 0.213 0.088 33.931 Conclusion Samples of steel 40Х and ШХ-15 were used for the experiment. The experiments carried out confirmed that the surface roughness of the boundary layer after ion nitriding improved, namely, the step of irregularities, the difference between tops and troughs of the relief decreases, the area of irregularities decreases, which in turn leads to an increase in the surface contact area, a decrease in the contact load. 80 Problems of Tribology References 1.Kaplun, P.V. Influence of Hydrogen on the Ion Nit riding of Steels (2018) Materials Science, 53 (6), pp. 818-822 DOI: 10.1007/s11003-018-0141-z 2. P. V. Kaplun, V. А. Honchar, Т. V. Donchenko. Contact Durability of Steels After Ion Nit riding in Hydrogen-Free Media Materials Science, November 2019, Volume 55, Issue 3, pp 424–429 DOI:10.31891/2079-1372-2018-90-4-80-84 3. P.V. Kaplun, E.B. Soroka, A.V. Snozik/ The Impact of Hydrogen-Free Ion Nit riding on Physico mechanical and Performance Characteristics of Hard Alloys T5K10 and T15K6. 2018, Sverkhtverdye Materially, 2018, Vol. 40, No. 6, pp. 26–35 DOI: 10.3103/S1063457618060035 4. P.V.Kaplun, B.A. Lyashenko, O.Y. Rudyk, V.A. Gonchar / Life of Boride Coatings on Steels Under Cyclic Contact Load. Strength of Materials. 2021. Vol. 53. № 2. pp 291–296.DOI: 10.1007/s11223-021-00288- w 5 Molebny V.V., Kamerman G.W., Ilchenko L.M., Kolenov S.O., Goncharov V.O., Smirnov E.M., “Three-beam scanning laser radar profilometer”, Proc. SPIE, 1998, Vol. 3380, P. 280-283. 6 Yano T., Kawabuchi M., Fukumoto A., Watanabe A. TeO2 acousto-optic Bragg light deflector without midband degeneracy // Appl. Phys. Lett. (USA), vol.26, no.12, p.689-91 (1975). https://doi.org/10.1007/s11223-021-00288-w https://doi.org/10.1007/s11223-021-00288-w Problems of Tribology 81 Побережний М.М. Каплун П.В. Каленов С.О. Дослідження кінетики зношування сталей з точки зору положень адгезійно-гідродинамічної теорії зношування Стаття присвячена дослідженню зносостійкості поверхневого шару сталей 40Х і ШХ15, при терті кочення в мастилі І-20. Проведено порівняння поверхневого шару зразків сирих та азотованих сталей, до та після випробувань. Проведене дослідження тонкої мікроструктури зразків за допомого мікроскопу ЛДФП, дозволило зробити висновок, що у зразках які були піддані іонному азотуванню, покращились показники шорсткості, що в свою чергу збільшило площу лінійного контакту, зменшилось контактне навантаження. Побудована графічна залежність показників шорсткості. Після проведених випробувань можна зробити висновок що азотована сталь має великий ресурс роботи, а саме велику твердість, стійкість проти спрацювання, краща витривалість та корозостійкість. Виявлено доцільність проведення подальших досліджень з визначення впливу ХТО на механізми зношування поверхонь та шляхів підвищення їх зносостійкості. Ключові слова: випробування, спрацювання, тертя, 40Х, ШХ15, іонне азотування, зразок, шорсткість, І-20.