Evaluation of Lubricating Ability of Solid Lubricants in Diamond Grinding of Difficult-to-machine Materials

Evaluation of Lubricating Ability of Solid Lubricants in Diamond Grinding of Difficult-to-machine Materials | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Evaluation of Lubricating Ability of Solid Lubricants in Diamond Grinding of Difficult-to-machine Materials Aleksandr Rudnev, Oksana Titarenko, Alexey Kotliar, Magomediemin Gasanov, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5759822/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Titanium alloys and nickel-based stainless steels are attractive materials for the aerospace industry because of high-strength, heat resistance, corrosion resistance. However, these materials are notorious for poor thermal properties and are classified as difficult-to-machine materials. The problems are attributed to the high specific energy and the large amount of cutting fluid consumed. Paper presents the results of the elimination of fluid coolants by solid lubricants (SLs) in diamond grinding of titanium alloy VT22 and heat-resistant stainless steel 10Cr11Ni23Ti3MoB. To study the impact of various compositions of SL on grinding performance, the cutting force and surface roughness were evaluated and compared with dry grinding. The best lubricating ability in grinding with low feeds has stearic acid (steel) and stearic acid with boron nitride (VT22). A good lubricating ability in grinding with increased feeds has stearic acid with boron nitride (steel) and stearic acid with molybdenum disulfide or with boron nitride (VT22). Lubricating Ability Diamond Grinding Difficult-To-Machine Materials Solid Lubricant Cutting Force Surface Roughness Figures Figure 1 Figure 2 Figure 3 1. Introduction All advances in military technology, particularly in aviation, are based on the extensive use of structural materials with high- strength, heat and corrosion resistance, high fatigue resistance, and unchanged physical and mechanical characteristics over a wide temperature range. These materials primarily include high-strength titanium alloys and heat-resistant stainless steels alloyed with nickel (more than 20%). Among the critical parts of aircraft construction, special emphasis is placed on power elements and welded assemblies of airframes (load-bearing beams, spars, bulkheads, assemblies of hinged units, ribs, flaps, and slat tracks), power elements and landing gear assemblies (braces, rocker trolley, slotted joints, brake levers) [1]. The unique properties of these alloys make them indispensable for landing gear assemblies, aircraft engine turbine blades, and vortex combustion chamber parts [2]. From a technological point of view, manufacturing such complex elements of modern technology is complicated because the materials are difficult to cast, process under pressure, weld, and cut. In general, they are considered difficult-to-machine. Despite the complexity of the part's shape, ensuring high surface quality can be achieved only through a special approach to its formation at all stages of production. In this process, the final (finishing) stages are critical for creating the high quality of the surface layer. For most parts made of difficult-to-machine alloys, the processes of finishing abrasive treatment (grinding) have become the only possibility to ensure the accuracy of shape and size; obtain the required surface roughness; and determine the physical and mechanical properties of the surface layer, thereby guaranteeing high functionality, reliability, and durability of the parts. However, grinding processes, owing to their significant energy consumption, require substantial costs for their implementation (20-25% of the total production process costs [3]). These costs are related primarily to the use of large amounts of lubricants and coolants, and the reduction in their harmful effects. Because of global trends to increase the environmental sustainability of manufacturing [4] and protection of natural resources, the technologies of minimal [5] and solid lubrication (SL), the use of multilayer grinding wheels with grains of various sizes and shapes [6], and the optimization of grinding mode parameters while considering the conditions of the surface of the grinding tool [7] are becoming increasingly relevant. The results of previous research [8, 9] proved the effectiveness of SLs (technical stearin, sebacic acid, and their mixture, a mixture of stearic acid and molybdenum disulfide) in diamond grinding of hard alloys and heat-resistant steel. Expanding the technological capabilities of grinding difficult-to-machine materials at different stages (preliminary, final) by studying the cutting force characteristics and surface quality parameters using different compositions of SLs is a primary task of a broader implementation of SLs at the most responsible final stages of environment friendly machining critical components for aviation. 2. Experimental details For the experimental studies, strategically important difficult-to-machine materials for aircraft construction were selected: titanium alloy VT22 (analog Ti 55531) and heat-resistant dispersion-hardened high-alloy stainless steel 10X11H23T3MR (X10NiCrTiMoAlMnB 25-15-3-1 according to EN 10027-1). Grinding the mentioned materials is difficult because of their special properties. Titanium alloys are notorious for their high chemical activity, low thermal conductivity, and poor antifriction properties. This leads to the material adhering to the grinding wheels, high temperatures in the grinding zone, and deterioration of the surface quality. Similar problems arise in the process of grinding heat-resistant corrosion-resistant steels, which are aggravated by high viscosity and even lower thermal conductivity (12 W/m K compared with 22 W/m K for VT22). The grinding surface area of the experimental samples is 200 mm² for the VT22 alloy (rectangle 10 x 20 mm) and 255 mm² for the stainless steel (circle Ø 18 mm). The mechanical processing was conducted via diamond grinding (DG) with wheels on a Bakelite bond: AC4 50/40 100% B2-01 on the revamped universal sharpening machine model 3D642E. The technological grinding modes were selected based on the basis of preliminary testing: a cutting speed Vs = 25 m/s, and a longitudinal speed – of 1 m/min. Grinding was performed with transverse feeds f tr = 0.005; 0.01; 0.015 mm/double pass (dp). The selection of the transverse feed index as a studied parameter was based on the available data [9] regarding its prominent role in the formation of the contact temperature in the grinding zone, and, therefore, its influence on the quality of the machined surface and the technological parameters of the process. For the performance comparison study, 5 SLs compositions made from the components listed in Table 1 were selected. The main fillers of modern environmentally friendly lubricants are saturated carbohydrates and their derivatives [3], such as stearic acid. As antifriction, and anti-wear modifiers, the use of substances with a hexagonal structure: such as graphite, molybdenum disulfide, and boron nitride is effective. The rational concentration of mineral additives is usually in the range of 20...40 %. SLs composition was used in the form of a pencil Ø 12 mm. Lubrication was carried out by contacting the diamond wheel in an operation mode for 1 to 2 s every 2 passes on the 3rd pass. Table 1. Composition of experimental solid lubricants. Components Chemical formula Content in solid lubricant, %, composition number 1 2 3 4 5 6 Stearic acid СН 3 (СН 2 ) 16 СО 2 Н - 65 100 90 80 65 Azelaic acid СО 2 Н(СН 2 ) 7 СО 2 Н - Molybdenum disulfide MoS 2 - 35 Hexagonal boron nitride BN - 20 35 Bell bronze Cu – 78…82% Sn – 18…22% - 10 The impact of SLs on the grinding process was evaluated by the tangential component of the cutting force Ft , which determines the force to overcome the elastic and plastic deformation of the processed material and the wear of abrasive grains and bonds. Measurements were carried out under a rigid grinding scheme with a laboratory experimental one-component dynamometer (Fig. 1). The surface quality was assessed by the roughness parameter Ra (arithmetic average of roughness profile) measured on profilometer-profilograph SURTRONIC 3+ (Taylor Hobson). To account for uncertainties, all the experiments were repeated five times, and their mean values were reported along with the standard deviation. 3. Results and Discussion The analysis of the research results (Fig. 2-3 - bar charts) indicates that under diamond grinding conditions, whether dry or with SLs, the tangential component Ft predictably increases with an f tr increase [10]. This is in agreement with the results reported in the literature and is due to the productive components of the force (shearing, micro fracturing, secondary ploughing). Typically, this dependence has a nonlinear character [11] with different degrees of proportionality in separate segments of the studied values of f tr . The dry grinding of steel 10X11N23T3MR (Fig. 2) with a f tr = 0.005 mm/dp is characterized by the lowest values of Ft . These values are significantly greater (twice as high) for the VT22 alloy (Fig. 3). A further f tr increase to 0.01 mm/dp reduces the difference between the materials by 40%. At a feed rate f tr = 0.015 mm/dp, an abnormally high tangential force Ft = 14.5 N is observed on steel, which is 1.3 times greater than that for the titanium alloy. Such increase in strength can be attributed for the special physical and mechanical properties of the materials, such as their high viscosity, tendency to stick, and adhesive activity, particularly those of the titanium alloy. All this leads to the emergence of so-called “unproductive” friction forces, which are particularly significant for steel. Unlike the productive components of the cutting force, unproductive forces essentially do not depend on the feed rate [12]. Lubrication of the grinding wheel with SLs test compounds (Nos. 1-6) led to a clear decrease in the Ft force during processing of the high-alloy steel and titanium alloy in almost all the processing modes. This testifies to the effectiveness of the lubricating action of the SLs as a whole, which was demonstrated by the reduction in frictional forces between the sample surface and the grinding wheel. The best result in reducing the cutting force, and consequently the energy charges, was achieved by grinding steel 10X11H23T3MR with nearly all the SLs used. Even if the mode with a f tr = 0.015 mm/dp, where the value of the initial “dry” force Ft was abnormally high, was excluded, significant improvements were observed at lower feed rates (0.005 and 0.010 mm/dp): depending on the processing mode and SLs composition in general, the force Ft decreased by 1.6 - 6.6 times. The order of SLs effectiveness depended on the feed rate. In fact, the best result was achieved with SLs No. 3 (stearic acid 100%) at f tr = 0.005 … 0.010 mm/dp, whereas at a f tr = 0.015 mm/dp, the best result was demonstrated for SLs No. 6 (stearic acid 65% + BN 35%). The SLs effectiveness for grinding the VT22 alloy (Fig. 3) was comparatively lower, whereas for SLs Nos. 3 and 5, it was observed only at f tr = 0.005…0.010 mm/dp. This confirms the idea [12] that friction forces play a prominent role at low feed rates. In general, the range of the Ft reduction coefficients during VT22 processing, was 1.1...1.7, depending on the processing mode and SLs composition. SLs No. 3 (stearic acid 100%) provided the maximum Ft reduction coefficient, whereas SLs No. 2 (stearic acid 65% + MoS 2 35%) provided the minimum Ft reduction coefficient. Studies of surface roughness made it possible to adjust the previous recommendations regarding the selection of SLs composition. It is worth paying attention (Figs. 2, 3 - line graphs) to the unambiguously positive effect of all SLs compositions on the surface quality of both materials in almost the entire range of transverse feeds. However, there is no unequivocal correlation between the results of the two series of studies. In general, a lower level of cutting force while grinding steel becomes apparent also in significantly lower (by 0.7...2.8 times) roughness values compared to titanium alloy. The reason for this is the different initial value of the hardness of the materials. In the "softer" substance VT22 (HV=2.8…3.6GPa) the depth of immersion of the diamond grain is greater than in the steel 10Х11Н23Т3МR (HV=3.9GPa). In the case of grinding steel with low feed f tr = 0.005 mm/dp, the results of roughness confirm the best lubricating ability of SLs No. 3 (stearic acid 100%). There is no point in adding any anti-wear modifiers to the SLs composition at the final stages of grinding (machining with small allowances). Their role becomes noticeable with an increase in feed to f tr = 0.015 mm/dp, especially the BN component. Compositions No. 4, 5, 6 provide the lowest level of surface roughness (Ra ≤ 0.36 μm). Taking into account the significant cutting force Ft by grinding with SLs No. 4 (Fig. 2 - bar chart), compositions No. 5, 6 with BN modifier in the amount of 20% and 35%, respectively, should be considered the most appropriate for previous grinding modes (allowance volume up to 3.8 mm 3 ). The BN component has a greater influence on the lubricating ability of the SLs by grinding of titanium alloy, especially in the modes with small feeds (Fig. 3 - line graphs). Compared to dry grinding (Ra = 0.51...0.58 μm), compositions No. 5, 6 demonstrate a decrease in roughness by 1.7...2.2 times. As the feed increases, the role of the BN component decreases slightly, and for the previous grinding modes with f tr up to 0.015 mm/dp, composition No. 6 (BN 35%) shows the best level of roughness (34% improvement). However, in terms of cutting force Ft , composition No. 6 is inferior to composition No. 2 with a MoS 2 (35%) modifier. Accordingly, at the preliminary stages of grinding with feeds (0.01 and 0.015 mm/pass) both compositions can be effectively applied. Composition No. 4 in relation to the others showed minimal lubricating ability (6...19% improvement). Table 2 summarizes the final recommendations for the selection of the SL composition for grinding the two researched difficult-to-machine materials at different stages. Table 2. Recommendations for the selection of the SL composition for grinding of difficult-to-machine materials. Difficult-to-machine material Grinding mode Solid lubricant composition number (acc. Tab.1) Cutting speed, m/s Transverse feed, mm/dp 10X11H23T3MR heat-resistant steel 25 0,005 3 0,01 3, 5, 6 0,015 5 VT22 titanium alloy 0,005 5, 6 0,01 2, 6 0,015 2, 6 Comparing the results of the cutting force and roughness values shows that the most qualitative correlation is observed in modes with small feeds, especially in the case of steel. This makes it possible to make a preliminary assessment of the lubricating ability of SLs using surface roughness parameters. In general, the effectiveness of reducing the force load and improving the surface roughness largely depends on the nature of the material, the SLs composition and the grinding modes. The conducted studies confirm the prospects of using solid lubricants by grinding difficult-to-machine materials for critical components for aviation in compliance with environmental requirements. Conclusions The advanced environmentally friendly methods of finishing processing for difficult-to-machine materials focus on reducing the use of harmful substances and water resources. The experimental research presented aims to examine an alternative lubrication method by means of a composition of solid substances. On the basis of the experimental results on diamond grinding of titanium alloy VT22 and heat-resistant stainless steel 10X11H23T3MR, the following conclusions were done: 1) The effectiveness of solid lubricating materials, which should provide better grinding conditions, should be evaluated by a set of parameters - the tangential component of the cutting force, which generally characterizes friction work, and the surface roughness characteristics. 2) SL is the most effective method for grinding heat-resistant stainless steel 10X11H23T3MR, especially within the feed range of 0.005-0.01 mm/dp for SLs No. 3, which is based on stearic acid (100 %). The corresponding values of the tangential component are 0.4-0.8 N. SLs No. 5 (stearic acid 80% + BN 20%) and No. 6 (stearic acid 65% + BN 35%) consistently demonstrated good lubricating ability over the entire feed range. 3) The lubricating ability of the studied SL compositions in the processing of titanium alloy VT 22 is somewhat worse than that of steel 10X11H23T3MR. However, with feeds up to 0.01 mm/dp, they can still effectively reduce the friction work. The best results were achieved via SLs Nos. 5, 6, based on stearic acid and boron nitride (Ra=0.24…0.3 μm). Grinding with increased feeds (up to 0.015 mm/dp) should be carried out with SLs No. 2 (stearic acid 65% + MoS 2 35%) or No. 6 (stearic acid 65% + BN 35%). 4) All five of the studied SL compositions can effectively improve the grinding conditions for difficult-to-machine materials, especially in range of small feeds at the final stages of grinding. Stearic acid should be considered a basis for making SLs, with further improvement of their composition. Further research aims to evaluate the lubricating ability of the proposed SLs in more productive grinding processes with speeds exceeding 25 m/s. Abbreviations Vs Cutting speed f tr Transverse feed Ft Tangential component of the cutting force Ra Roughness parameter (arithmetic average of roughness profile) Declarations Acknowledgments This work was carried out as part of the Research Work “Development of technological foundations for high-speed diamond grinding of difficult-to-machine materials for aircraft products using solid lubricants” supported by the Ministry of Education and Science of Ukraine. The authors are indebted to the financial support of this research. Funding This work was supported by the Ministry of Education and Science of Ukraine (Grant Number 0124U000678). Conflict of Interest The authors have no relevant financial or non-financial interests to disclose. Author Contributions All authors contributed to the study conception and design. Material preparation was performed by Aleksandr Rudnev, data collection was performed by Alexey Kotliar, and analysis was performed by Magomedemin Gasanov and Pavel Kalinin. The first draft of the manuscript was written by Oksana Titarenko and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. References Putyrskiy, S. V. et al.: Benefits and Applications of High-Strength Titanium Alloys, Russ. Engin. Res. , 38 (12) (2018) 945–948. https://doi.org/10.3103/S1068798X18120419 Zhu, T. et al.: Research progress of eco‑friendly grinding technology for aviation nickel‑based superalloys, Int. J. Adv. Manuf. Technol. , Vol. 126 (2023) 2863–2886. https://doi.org/10.1007/s00170-023-11336-x Sharif, M. N. et al.: Potential of alternative lubrication strategies for metal cutting processes: a review, Int. J. Adv. Manuf. Technol. , 89 (5-8) (2023) 2447–2479. https://doi.org/10.1007/s00170-016-9298-5 Cai, M. R. et al.: Lubricating a bright future: Lubrication contribution to energy saving and low carbon emission, Sci. China. Tech. Sci. , 56 (2013) 2888-2913. https://doi.org/10.1007/s11431-013-5403-2 Ali, S. H. et al.: Recent developments in MQL machining of aeronautical materials: A comparative review, Chin. J. Aeronaut. , (2024), https://doi.org/10.1016/j.cja.2024.01.018. Lipi´nski, D. et al.: Analysis of the Cutting Abilities of the Multilayer Grinding Wheels – Case of Ti-6Al-4V Alloy Grinding, Materials 15 (1) (2022) 1-13. https://doi.org/10.3390/ma15010022 Kacalak, W. et al.: Selected Aspects of Precision Grinding Processes Optimization, Materials 17 (2024) 607-624. https://doi.org/10.3390/ma17030607 Rudnev, A. et al.: Diamond Spark Grinding of Hard Alloys Using Solid Lubricants, Advances in Design, Simulation and Manufacturing (DSMIE) , Lecture Notes in Mechanical Engineering (2021) 114 – 122. https://doi.org/10.1007/978-3-030-77719-7_12 Sevidova, E. et al.: An impact of Solid Lubrication on the Diamond Grinding Characteristics of Difficult-to-Machine Materials, Advances in Design, Simulation and Manufacturing (DSMIE ), Lecture Notes in Mechanical Engineering (2023) 337 – 346. https://doi.org/10.1007/978-3-031-32767-4_32 Panaioti, V. et al.: Assessing the Effectiveness of Solid Lubricants, Russ. Engin. Res., 38 (6) (2018) 493–497. https://doi.org/10.3103/S1068798X1806014X Panaioti, V. et al.: Applying Solid Lubricant to the Grinding-Wheel Surface, Russ. Engin. Res . 37 (4) (2017) 359–362. https://doi.org/10.3103/S1068798X17040165 Ravuri, B.P. et al.: Performance evaluation of grinding wheels impregnated with graphene nanoplatelets, Int. J. Adv. Manuf. Technol., 85 (2016) 2235–2245. https://doi.org/10.1007/s00170-015-7459-6 Additional Declarations No competing interests reported. Supplementary Files Authorinformation.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Introduction","content":"\u003cp\u003eAll advances in military technology, particularly in aviation, are based on the extensive use of structural materials with high- strength, heat and corrosion resistance, high fatigue resistance, and unchanged physical and mechanical characteristics over a wide temperature range. These materials primarily include high-strength titanium alloys and heat-resistant stainless steels alloyed with nickel (more than 20%). Among the critical parts of aircraft construction, special emphasis is placed on power elements and welded assemblies of airframes (load-bearing beams, spars, bulkheads, assemblies of hinged units, ribs, flaps, and slat tracks), power elements and landing gear assemblies (braces, rocker trolley, slotted joints, brake levers) [1]. The unique properties of these alloys make them indispensable for landing gear assemblies, aircraft engine turbine blades, and vortex combustion chamber parts [2].\u003c/p\u003e\n\u003cp\u003eFrom a technological point of view, manufacturing such complex elements of modern technology is complicated because the materials are difficult to cast, process under pressure, weld, and cut. In general, they are considered difficult-to-machine. Despite the complexity of the part's shape, ensuring high surface quality can be achieved only through a special approach to its formation at all stages of production. In this process, the final (finishing) stages are critical for creating the high quality of the surface layer.\u003c/p\u003e\n\u003cp\u003eFor most parts made of difficult-to-machine alloys, the processes of finishing abrasive treatment (grinding) have become the only possibility to ensure the accuracy of shape and size; obtain the required surface roughness; and determine the physical and mechanical properties of the surface layer, thereby guaranteeing high functionality, reliability, and durability of the parts. However, grinding processes, owing to their significant energy consumption, require substantial costs for their implementation (20-25% of the total production process costs [3]). These costs are related primarily to the use of large amounts of lubricants and coolants, and the reduction in their harmful effects. Because of global trends to increase the environmental sustainability of manufacturing [4] and protection of natural resources, the technologies of minimal [5] and solid lubrication (SL), the use of multilayer grinding wheels with grains of various sizes and shapes [6], and the optimization of grinding mode parameters while considering the conditions of the surface of the grinding tool [7] are becoming increasingly relevant.\u003c/p\u003e\n\u003cp\u003eThe results of previous research [8, 9] proved the effectiveness of SLs (technical stearin, sebacic acid, and their mixture, a mixture of stearic acid and molybdenum disulfide) in diamond grinding of hard alloys and heat-resistant steel. Expanding the technological capabilities of grinding difficult-to-machine materials at different stages (preliminary, final) by studying the cutting force characteristics and surface quality parameters using different compositions of SLs is a primary task of a broader implementation of SLs at the most responsible final stages of environment friendly machining critical components for aviation.\u003c/p\u003e"},{"header":"2. Experimental details","content":"\u003cp\u003eFor the experimental studies, strategically important difficult-to-machine materials for aircraft construction were selected: titanium alloy VT22 (analog Ti 55531) and heat-resistant dispersion-hardened high-alloy stainless steel 10X11H23T3MR (X10NiCrTiMoAlMnB 25-15-3-1 according to EN 10027-1).\u003c/p\u003e\n\u003cp\u003eGrinding the mentioned materials is difficult because of their special properties. Titanium alloys are notorious for their high chemical activity, low thermal conductivity, and poor antifriction properties. This leads to the material adhering to the grinding wheels, high temperatures in the grinding zone, and deterioration of the surface quality. Similar problems arise in the process of grinding heat-resistant corrosion-resistant steels, which are aggravated by high viscosity and even lower thermal conductivity (12 W/m K compared with 22 W/m K for VT22).\u003c/p\u003e\n\u003cp\u003eThe grinding surface area of the experimental samples is 200\u0026nbsp;mm\u0026sup2; for the VT22 alloy (rectangle 10\u0026nbsp;x\u0026nbsp;20\u0026nbsp;mm) and 255\u0026nbsp;mm\u0026sup2; for the stainless steel (circle \u0026Oslash; 18\u0026nbsp;mm).\u003c/p\u003e\n\u003cp\u003eThe mechanical processing was conducted via diamond grinding (DG) with wheels on a Bakelite bond: AC4 50/40 100% B2-01 on the revamped universal sharpening machine model 3D642E.\u003c/p\u003e\n\u003cp\u003eThe technological grinding modes were selected based on the basis of preliminary testing: a cutting speed \u003cem\u003eVs\u003c/em\u003e = 25 m/s, and a longitudinal speed \u0026ndash; of 1 m/min. Grinding was performed with transverse feeds \u003cem\u003ef\u003csub\u003etr\u003c/sub\u003e\u003c/em\u003e = 0.005; 0.01; 0.015 mm/double pass (dp). The selection of the transverse feed index as a studied parameter was based on the available data [9] regarding its prominent role in the formation of the contact temperature in the grinding zone, and, therefore, its influence on the quality of the machined surface and the technological parameters of the process.\u003c/p\u003e\n\u003cp\u003eFor the performance comparison study, 5 SLs compositions made from the components listed in Table 1 were selected. The main fillers of modern environmentally friendly lubricants are saturated carbohydrates and their derivatives [3], such as stearic acid. As antifriction, and anti-wear modifiers, the use of substances with a hexagonal structure: such as graphite, molybdenum disulfide, and boron nitride is effective. The rational concentration of mineral additives is usually in the range of 20...40 %. SLs composition was used in the form of a pencil \u0026Oslash; 12 mm. Lubrication was carried out by contacting the diamond wheel in an operation mode for 1 to 2 s every 2 passes on the 3rd pass.\u003c/p\u003e\n\u003cp\u003eTable 1. Composition of experimental solid lubricants.\u003c/p\u003e\n\u003cdiv align=\"Left\"\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"491\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 75px;\"\u003e\n \u003cp\u003eComponents\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 95px;\"\u003e\n \u003cp\u003eChemical formula\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"6\" style=\"width: 283px;\"\u003e\n \u003cp\u003eContent in solid lubricant, %,\u003cbr\u003e\u0026nbsp;composition number\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003eStearic acid\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003eСН\u003csub\u003e3\u003c/sub\u003e(СН\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e16\u003c/sub\u003eСО\u003csub\u003e2\u003c/sub\u003eН\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e65\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e65\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003eAzelaic acid\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003eСО\u003csub\u003e2\u003c/sub\u003eН(СН\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e7\u003c/sub\u003eСО\u003csub\u003e2\u003c/sub\u003eН\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003eMolybdenum disulfide\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003eMoS\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003eHexagonal\u003cbr\u003e\u0026nbsp;boron nitride\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003eBN\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003eBell bronze\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003eCu \u0026ndash; 78\u0026hellip;82%\u003c/p\u003e\n \u003cp\u003eSn \u0026ndash; 18\u0026hellip;22%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eThe impact of SLs on the grinding process was evaluated by the tangential component of the cutting force \u003cem\u003eFt\u003c/em\u003e, which determines the force to overcome the elastic and plastic deformation of the processed material and the wear of abrasive grains and bonds. Measurements were carried out under a rigid grinding scheme with a laboratory experimental one-component dynamometer (Fig. 1).\u003c/p\u003e\n\u003cp\u003eThe surface quality was assessed by the roughness parameter Ra (arithmetic average of roughness profile) measured on profilometer-profilograph SURTRONIC 3+ (Taylor Hobson).\u003c/p\u003e\n\u003cp\u003eTo account for uncertainties, all the experiments were repeated five times, and their mean values were reported along with the standard deviation.\u003c/p\u003e"},{"header":"3. Results and Discussion","content":"\u003cp\u003eThe analysis of the research results (Fig. 2-3 - bar charts) indicates that under diamond grinding conditions, whether dry or with SLs, the tangential component \u003cem\u003eFt\u003c/em\u003e predictably increases with an \u003cem\u003ef\u003csub\u003etr\u003c/sub\u003e\u003c/em\u003e increase [10]. This is in agreement with the results reported in the literature and is due to the productive components of the force (shearing, micro fracturing, secondary ploughing). Typically, this dependence has a nonlinear character [11] with different degrees of proportionality in separate segments of the studied values of \u003cem\u003ef\u003csub\u003etr\u003c/sub\u003e\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003eThe dry grinding of steel 10X11N23T3MR (Fig. 2) with a \u003cem\u003ef\u003csub\u003etr\u003c/sub\u003e\u003c/em\u003e = 0.005 mm/dp is characterized by the lowest values of \u003cem\u003eFt\u003c/em\u003e. These values are significantly greater (twice as high) for the VT22 alloy (Fig. 3). A further \u003cem\u003ef\u003csub\u003etr\u003c/sub\u003e\u003c/em\u003e increase to 0.01 mm/dp reduces the difference between the materials by 40%. At a feed rate \u003cem\u003ef\u003csub\u003etr\u003c/sub\u003e\u003c/em\u003e = 0.015 mm/dp, an abnormally high tangential force \u003cem\u003eFt\u003c/em\u003e = 14.5 N is observed on steel, which is 1.3 times greater than that for the titanium alloy.\u003c/p\u003e\n\u003cp\u003eSuch increase in strength can be attributed for the special physical and mechanical properties of the materials, such as their high viscosity, tendency to stick, and adhesive activity, particularly those of the titanium alloy. All this leads to the emergence of so-called \u0026ldquo;unproductive\u0026rdquo; friction forces, which are particularly significant for steel. Unlike the productive components of the cutting force, unproductive forces essentially do not depend on the feed rate [12].\u003c/p\u003e\n\u003cp\u003eLubrication of the grinding wheel with SLs test compounds (Nos. 1-6) led to a clear decrease in the \u003cem\u003eFt\u003c/em\u003e force during processing of the high-alloy steel and titanium alloy in almost all the processing modes. This testifies to the effectiveness of the lubricating action of the SLs as a whole, which was demonstrated by the reduction in frictional forces between the sample surface and the grinding wheel.\u003c/p\u003e\n\u003cp\u003eThe best result in reducing the cutting force, and consequently the energy charges, was achieved by grinding steel 10X11H23T3MR with nearly all the SLs used. Even if the mode with a \u003cem\u003ef\u003csub\u003etr\u003c/sub\u003e\u003c/em\u003e = 0.015 mm/dp, where the value of the initial \u0026ldquo;dry\u0026rdquo; force \u003cem\u003eFt\u003c/em\u003e was abnormally high, was excluded, significant improvements were observed at lower feed rates (0.005 and 0.010 mm/dp): depending on the processing mode and SLs composition in general, the force \u003cem\u003eFt\u003c/em\u003e decreased by 1.6 - 6.6 times.\u003c/p\u003e\n\u003cp\u003eThe order of SLs effectiveness depended on the feed rate. In fact, the best result was achieved with SLs No. 3 (stearic acid 100%) at \u003cem\u003ef\u003csub\u003etr\u003c/sub\u003e\u003c/em\u003e = 0.005 \u0026hellip; 0.010 mm/dp, whereas at a \u003cem\u003ef\u003csub\u003etr\u003c/sub\u003e\u003c/em\u003e = 0.015 mm/dp, the best result was demonstrated for SLs No. 6 (stearic acid 65% + BN 35%).\u003c/p\u003e\n\u003cp\u003eThe SLs effectiveness for grinding the VT22 alloy (Fig. 3) was comparatively lower, whereas for SLs Nos. 3 and 5, it was observed only at \u003cem\u003ef\u003csub\u003etr\u003c/sub\u003e\u003c/em\u003e = 0.005\u0026hellip;0.010 mm/dp. This confirms the idea [12] that friction forces play a prominent role at low feed rates.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn general, the range of the \u003cem\u003eFt\u003c/em\u003e reduction coefficients during VT22 processing, was 1.1...1.7, depending on the processing mode and SLs composition.\u003c/p\u003e\n\u003cp\u003eSLs No. 3 (stearic acid 100%) provided the maximum \u003cem\u003eFt\u003c/em\u003e reduction coefficient, whereas SLs No. 2 (stearic acid 65% + MoS\u003csub\u003e2\u003c/sub\u003e 35%) provided the minimum \u003cem\u003eFt\u003c/em\u003e reduction coefficient.\u003c/p\u003e\n\u003cp\u003eStudies of surface roughness made it possible to adjust the previous recommendations regarding the selection of SLs composition. It is worth paying attention (Figs. 2, 3 - line graphs) to the unambiguously positive effect of all SLs compositions on the surface quality of both materials in almost the entire range of transverse feeds. However, there is no unequivocal correlation between the results of the two series of studies.\u003c/p\u003e\n\u003cp\u003eIn general, a lower level of cutting force while grinding steel becomes apparent also in significantly lower (by 0.7...2.8 times) roughness values compared to titanium alloy. The reason for this is the different initial value of the hardness of the materials. In the \u0026quot;softer\u0026quot; substance VT22 (HV=2.8\u0026hellip;3.6GPa) the depth of immersion of the diamond grain is greater than in the steel 10Х11Н23Т3МR (HV=3.9GPa).\u003c/p\u003e\n\u003cp\u003eIn the case of grinding steel with low feed \u003cem\u003ef\u003csub\u003etr\u003c/sub\u003e\u003c/em\u003e = 0.005 mm/dp, the results of roughness confirm the best lubricating ability of SLs No. 3 (stearic acid 100%). There is no point in adding any anti-wear modifiers to the SLs composition at the final stages of grinding (machining with small allowances). Their role becomes noticeable with an increase in feed to \u003cem\u003ef\u003csub\u003etr\u003c/sub\u003e\u003c/em\u003e = 0.015 mm/dp, especially the BN component. Compositions No. 4, 5, 6 provide the lowest level of surface roughness (Ra \u0026le; 0.36 \u0026mu;m). Taking into account the significant cutting force \u003cem\u003eFt\u003c/em\u003e by grinding with SLs No. 4 (Fig. 2 - bar chart), compositions No. 5, 6 with BN modifier in the amount of 20% and 35%, respectively, should be considered the most appropriate for previous grinding modes (allowance volume up to 3.8 mm\u003csup\u003e3\u003c/sup\u003e).\u003c/p\u003e\n\u003cp\u003eThe BN component has a greater influence on the lubricating ability of the SLs by grinding of titanium alloy, especially in the modes with small feeds (Fig. 3 - line graphs). Compared to dry grinding (Ra = 0.51...0.58 \u0026mu;m), compositions No. 5, 6 demonstrate a decrease in roughness by 1.7...2.2 times. As the feed increases, the role of the BN component decreases slightly, and for the previous grinding modes with \u003cem\u003ef\u003csub\u003etr\u003c/sub\u003e\u003c/em\u003e up to 0.015 mm/dp, composition No. 6 (BN 35%) shows the best level of roughness (34% improvement). However, in terms of cutting force \u003cem\u003eFt\u003c/em\u003e, composition No. 6 is inferior to composition No. 2 with a MoS\u003csub\u003e2\u003c/sub\u003e (35%) modifier. Accordingly, at the preliminary stages of grinding with feeds (0.01 and 0.015 mm/pass) both compositions can be effectively applied. Composition No. 4 in relation to the others showed minimal lubricating ability (6...19% improvement).\u003c/p\u003e\n\u003cp\u003eTable 2 summarizes the final recommendations for the selection of the SL composition for grinding the two researched difficult-to-machine materials at different stages.\u003c/p\u003e\n\u003cp\u003eTable 2. Recommendations for the selection of the SL composition for grinding of difficult-to-machine materials.\u003c/p\u003e\n\u003cdiv align=\"Left\"\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"473\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 108px;\"\u003e\n \u003cp\u003eDifficult-to-machine material\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 166px;\"\u003e\n \u003cp\u003eGrinding mode\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 180px;\"\u003e\n \u003cp\u003eSolid lubricant composition number\u003cbr\u003e\u0026nbsp;(acc. Tab.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp\u003eCutting speed, m/s\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003eTransverse feed, mm/dp\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 108px;\"\u003e\n \u003cp\u003e10X11H23T3MR heat-resistant steel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"6\" style=\"width: 65px;\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e0,005\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e0,01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e3, 5, 6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e0,015\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 108px;\"\u003e\n \u003cp\u003eVT22\u003cbr\u003e\u0026nbsp;titanium alloy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e0,005\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e5, 6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e0,01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e2, 6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e0,015\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e2, 6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eComparing the results of the cutting force and roughness values shows that the most qualitative correlation is observed in modes with small feeds, especially in the case of steel. This makes it possible to make a preliminary assessment of the lubricating ability of SLs using surface roughness parameters.\u003c/p\u003e\n\u003cp\u003eIn general, the effectiveness of reducing the force load and improving the surface roughness largely depends on the nature of the material, the SLs composition and the grinding modes. The conducted studies confirm the prospects of using solid lubricants by grinding difficult-to-machine materials for critical components for aviation in compliance with environmental requirements.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThe advanced environmentally friendly methods of finishing processing for difficult-to-machine materials focus on reducing the use of harmful substances and water resources. The experimental research presented aims to examine an alternative lubrication method by means of a composition of solid substances.\u003c/p\u003e\n\u003cp\u003eOn the basis of the experimental results on diamond grinding of titanium alloy VT22 and heat-resistant stainless steel 10X11H23T3MR, the following conclusions were done:\u003c/p\u003e\n\u003cp\u003e1) The effectiveness of solid lubricating materials, which should provide better grinding conditions, should be evaluated by a set of parameters - the tangential component of the cutting force, which generally characterizes friction work, and the surface roughness characteristics.\u003c/p\u003e\n\u003cp\u003e2) SL is the most effective method for grinding heat-resistant stainless steel 10X11H23T3MR, especially within the feed range of 0.005-0.01\u0026nbsp;mm/dp for SLs No.\u0026nbsp;3, which is based on stearic acid (100\u0026nbsp;%). The corresponding values of the tangential component are 0.4-0.8\u0026nbsp;N. SLs No.\u0026nbsp;5 (stearic acid 80% + BN 20%) and No.\u0026nbsp;6 (stearic acid 65% + BN 35%) consistently demonstrated good lubricating ability over the entire feed range.\u003c/p\u003e\n\u003cp\u003e3) \u0026nbsp;The lubricating ability of the studied SL compositions in the processing of titanium alloy VT 22 is somewhat worse than that of steel 10X11H23T3MR. However, with feeds up to 0.01\u0026nbsp;mm/dp, they can still effectively reduce the friction work. The best results were achieved via SLs Nos.\u0026nbsp;5, 6, based on stearic acid and boron nitride (Ra=0.24\u0026hellip;0.3\u0026nbsp;\u0026mu;m). Grinding with increased feeds (up to 0.015\u0026nbsp;mm/dp) should be carried out with SLs No. 2 (stearic acid 65% + MoS\u003csub\u003e2\u003c/sub\u003e 35%) or No. 6 (stearic acid 65% + BN 35%).\u003c/p\u003e\n\u003cp\u003e4) \u0026nbsp;All five of the studied SL compositions can effectively improve the grinding conditions for difficult-to-machine materials, especially in range of small feeds at the final stages of grinding. Stearic acid should be considered a basis for making SLs, with further improvement of their composition. Further research aims to evaluate the lubricating ability of the proposed SLs in more productive grinding processes with speeds exceeding 25 m/s.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cem\u003eVs\u003c/em\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eCutting speed\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cem\u003ef\u003c/em\u003e\u003csub\u003e\u003cem\u003etr\u003c/em\u003e\u003c/sub\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eTransverse feed\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cem\u003eFt\u003c/em\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eTangential component of the cutting force\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eRa\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eRoughness parameter (arithmetic average of roughness profile)\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003eAcknowledgments\u003c/p\u003e\n\u003cp\u003eThis work was carried out as part of the Research Work \u0026ldquo;Development of technological foundations for high-speed diamond grinding of difficult-to-machine materials for aircraft products using solid lubricants\u0026rdquo; supported by the Ministry of Education and Science of Ukraine. The authors are indebted to the financial support of this research.\u003c/p\u003e\n\u003cp\u003eFunding\u003c/p\u003e\n\u003cp\u003eThis work was supported by the Ministry of Education and Science of Ukraine (Grant Number 0124U000678).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eConflict of Interest\u003c/p\u003e\n\u003cp\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e\n\u003cp\u003eAuthor Contributions\u003c/p\u003e\n\u003cp\u003eAll authors contributed to the study conception and design. Material preparation was performed by Aleksandr Rudnev, data collection was performed by Alexey Kotliar, and analysis was performed by Magomedemin Gasanov and Pavel Kalinin. The first draft of the manuscript was written by Oksana Titarenko and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003ePutyrskiy, S. V. et al.: Benefits and Applications of High-Strength Titanium Alloys, \u003cem\u003eRuss. Engin. Res.\u003c/em\u003e, 38 (12) (2018) 945\u0026ndash;948. https://doi.org/10.3103/S1068798X18120419\u003c/li\u003e\n \u003cli\u003eZhu, T. et al.: Research progress of eco‑friendly grinding technology for aviation nickel‑based superalloys, \u003cem\u003eInt. J. Adv. Manuf. Technol.\u003c/em\u003e, Vol. 126 (2023) 2863\u0026ndash;2886.\u0026nbsp;https://doi.org/10.1007/s00170-023-11336-x\u003c/li\u003e\n \u003cli\u003eSharif, M. N. et al.: Potential of alternative lubrication strategies for metal cutting processes: a review, \u003cem\u003eInt. J. Adv. Manuf. Technol.\u003c/em\u003e, 89 (5-8) (2023) 2447\u0026ndash;2479. https://doi.org/10.1007/s00170-016-9298-5\u003c/li\u003e\n \u003cli\u003eCai, M. R. et al.: Lubricating a bright future: Lubrication contribution to energy saving and low carbon emission, \u003cem\u003eSci. China. Tech. Sci.\u003c/em\u003e, 56 (2013) 2888-2913. https://doi.org/10.1007/s11431-013-5403-2\u003c/li\u003e\n \u003cli\u003eAli, S. H. et al.: Recent developments in MQL machining of aeronautical materials: A comparative review, \u003cem\u003eChin. J. Aeronaut.\u003c/em\u003e, (2024), https://doi.org/10.1016/j.cja.2024.01.018.\u003c/li\u003e\n \u003cli\u003eLipi\u0026acute;nski, D. et al.: Analysis of the Cutting Abilities of the Multilayer Grinding Wheels \u0026ndash; Case of Ti-6Al-4V Alloy Grinding, \u003cem\u003eMaterials\u003c/em\u003e 15 (1) (2022) 1-13.\u0026nbsp;https://doi.org/10.3390/ma15010022\u003c/li\u003e\n \u003cli\u003eKacalak, W. et al.: Selected Aspects of Precision Grinding Processes Optimization, \u003cem\u003eMaterials\u003c/em\u003e 17 (2024) 607-624. https://doi.org/10.3390/ma17030607\u003c/li\u003e\n \u003cli\u003eRudnev, A. et al.: Diamond Spark Grinding of Hard Alloys Using Solid Lubricants, \u003cem\u003eAdvances in Design, Simulation and Manufacturing\u003c/em\u003e\u003cem\u003e(DSMIE)\u003c/em\u003e, Lecture Notes in Mechanical Engineering (2021) 114 \u0026ndash; 122. https://doi.org/10.1007/978-3-030-77719-7_12\u003c/li\u003e\n \u003cli\u003eSevidova, E. et al.: An impact of Solid Lubrication on the Diamond Grinding Characteristics of Difficult-to-Machine Materials, \u003cem\u003eAdvances in Design, Simulation and Manufacturing (DSMIE\u003c/em\u003e), Lecture Notes in Mechanical Engineering (2023) 337 \u0026ndash; 346. https://doi.org/10.1007/978-3-031-32767-4_32\u003c/li\u003e\n \u003cli\u003ePanaioti, V. et al.: Assessing the Effectiveness of Solid Lubricants, \u003cem\u003eRuss. Engin. Res.,\u003c/em\u003e 38 (6) (2018) 493\u0026ndash;497. https://doi.org/10.3103/S1068798X1806014X\u003c/li\u003e\n \u003cli\u003ePanaioti, V. et al.: Applying Solid Lubricant to the Grinding-Wheel Surface, \u003cem\u003eRuss. Engin. Res\u003c/em\u003e. 37 (4) (2017) 359\u0026ndash;362. https://doi.org/10.3103/S1068798X17040165\u003c/li\u003e\n \u003cli\u003eRavuri, B.P. et al.: Performance evaluation of grinding wheels impregnated with graphene nanoplatelets, \u003cem\u003eInt. J. Adv. Manuf. Technol.,\u003c/em\u003e 85 (2016) 2235\u0026ndash;2245. https://doi.org/10.1007/s00170-015-7459-6\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Lubricating Ability, Diamond Grinding, Difficult-To-Machine Materials, Solid Lubricant, Cutting Force, Surface Roughness","lastPublishedDoi":"10.21203/rs.3.rs-5759822/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5759822/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Titanium alloys and nickel-based stainless steels are attractive materials for the aerospace industry because of high-strength, heat resistance, corrosion resistance. However, these materials are notorious for poor thermal properties and are classified as difficult-to-machine materials. The problems are attributed to the high specific energy and the large amount of cutting fluid consumed. Paper presents the results of the elimination of fluid coolants by solid lubricants (SLs) in diamond grinding of titanium alloy VT22 and heat-resistant stainless steel 10Cr11Ni23Ti3MoB. To study the impact of various compositions of SL on grinding performance, the cutting force and surface roughness were evaluated and compared with dry grinding. The best lubricating ability in grinding with low feeds has stearic acid (steel) and stearic acid with boron nitride (VT22). A good lubricating ability in grinding with increased feeds has stearic acid with boron nitride (steel) and stearic acid with molybdenum disulfide or with boron nitride (VT22).","manuscriptTitle":"Evaluation of Lubricating Ability of Solid Lubricants in Diamond Grinding of Difficult-to-machine Materials","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-01-14 07:51:27","doi":"10.21203/rs.3.rs-5759822/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"dd5e3ce7-2c0f-4089-a1d7-fc8d007198bc","owner":[],"postedDate":"January 14th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-01-14T07:51:27+00:00","versionOfRecord":[],"versionCreatedAt":"2025-01-14 07:51:27","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5759822","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5759822","identity":"rs-5759822","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}