The life of metal forming dies, and the efficiency of tooling industries depends on the mechanica... more The life of metal forming dies, and the efficiency of tooling industries depends on the mechanical and wear properties of tool steel. These properties can be further improved by depositing the ceramic coating on heat-treated tool steel. There are many coating materials available with numerous excellent properties. But problem is how to select the best coating material. Compared to various studies related to material selection problems in the contrasting area of utilization, remarkably, few research work is done in tooling industries. In the present work, we have identified eight coating materials (alternatives) and nine evaluation criteria under the consultation of an expert in the tooling application and tribological field. To deal with this coating material selection problem, an integrated fuzzy-MADM method is proposed comprising BWM and fuzzy-MARCOS. This integrated fuzzy-MADM method is used to evaluate the alternative, and the obtained results are scrutinized under extensive use...
Bulletin of the Polytechnic Institute of Iași. Machine constructions Section
Technologies such additive manufacturing are slowly becoming more and more present on the market,... more Technologies such additive manufacturing are slowly becoming more and more present on the market, covering different areas of the industry due to its great potential. Even so, there are still many aspects which are unexplored or which can be improved. One of them being the study of the tribological proprieties for all these parts, which are produced through additive manufacturing methods, such as powder bed fusion, binder jetting, direct energy deposition, fused filament fabrication, material jetting, vat photopolymerization, and sheet lamination. The scope of this paper is to bring together the tribological proprieties for the 3D printed parts, and to have a critical analysis of these proprieties, in order to easily decide which printing method is suitable, depending of the working conditions of the printed component. In addition, this paper will describe the working principle for each technology, and the type of materials that are commonly used in the printing process. Depending o...
The use of biomass mixtures as a feedstock in the production of pellets requires optimization of ... more The use of biomass mixtures as a feedstock in the production of pellets requires optimization of the percentages of the components, since interactions occur during combustion between the components forming the blend (lignin, cellulose, and hemicellulose), affecting characteristics of pellets such as calorific value, ash content, fine fraction content, bulk density, and mechanical durability. Our study focuses on the assessment of the quality of pellets produced from biomass blends generated from pruning seabuckthorn and blackberry mixed with wheat straw. The results of literature data analysis and laboratory research show that wheat straw pellets exhibited the lowest calorific value (15.2 ± 0.2 MJ/Kg) and the highest ash content (5.7 ± 0.18%) while seabuckthorn and blackberry biomass pellets possessed significantly higher calorific value with low ash content. According to the maximization of the mixtures taken in the study, it was proved that the addition of up to 25% wheat straw re...
Shape Memory Alloys (SMA) have been researched extensively in the past forty years. The different... more Shape Memory Alloys (SMA) have been researched extensively in the past forty years. The different available compositions of these alloys can make them suitable for certain applications with specific requirements. The increasing demand for high precision machinery and equipment brought forward the need to search for alloys that that can perform better under stress than conventional materials. This is the case of Shape Memory Alloys. As their name suggests, these alloys can regain their initial shape after being subjected to external stresses, up to a specific degree. Due to the research carried out over the past two decades on these alloys, they became better known and more accessible, being tested in order to be integrated in various applications. One such application consists of using a shape memory alloy formed into disc springs in order to optimize the preloading of angular contact ball bearings. The tests were conducted using a device especially developed for this research, with the purpose of recording the friction torque evolution and the preload induced by disc springs during the operation of the rolling bearings in order to assess the possibility of using elastic elements for active ball bearings preloading systems.
IOP Conference Series: Materials Science and Engineering
Technology based on additive manufacturing is rapidly emerging and is being used in a wide range ... more Technology based on additive manufacturing is rapidly emerging and is being used in a wide range of industries. Meeting the precision and accuracy (P&A) requirements of 3D printed parts (shape and size tolerances, surface quality, etc.) is increasingly becoming an issue. This paper presents a critical analysis of the tribological problems encountered in 3D printing for parts manufactured through different types of technologies, such as powder bed fusion, binder jetting, direct energy deposition, material jetting, fused filament fabrication, vat photopolymerization, sheet lamination, and ultrasonic consolidation. For all these additive manufacturing technologies, this paper will present a brief description, classification, examples of materials used, and tribological problems of the obtained machine parts.
IOP Conference Series: Materials Science and Engineering, 2020
Reliability and maintenance play an important role in the field of rail vehicle systems. In order... more Reliability and maintenance play an important role in the field of rail vehicle systems. In order to be reliable, this type of transport needs continuous monitoring and regular maintenance. Regarding requested repair and maintenance interventions in relation to the probability of failure for each component, assembly or subassembly, additional information could be taken by data acquisition from sensors fitted to the locomotive bogies. The influence of the rail pattern configuration and the asymmetry of the positioning of both the traction motors and the gearbox on the amplitude and frequency of the introduced vibrations is considered. Fast and robust online signal processing algorithms are essential for designing a smart device. In this way, maintenance models can be created based on the state of the systems and integrated platforms can be produced in order to improve the diagnosis and expertise of a maintenance program. The paper presents the method of determining the vibrations ind...
Bulletin of the Polytechnic Institute of Iași. Machine constructions Section
Fractals and chaos theory provide means of modeling dynamic changes in micro and nano topography ... more Fractals and chaos theory provide means of modeling dynamic changes in micro and nano topography on friction surfaces caused by various tribological mechanisms and processes. Friction and wear phenomena in tribological systems can be interpreted on a macroscopic scale. With the development of miniaturized scale and nanoscale systems, it has been launched the hypothesis that macro-level systems cannot reflect the microscale and nanoscale phenomena. A conclusive case is given by the calculation of frictional torque in microscale orientation, in this situation being found that models created by bearing producers cannot validate experimental results. By applying the “box-counting” method, it is possible to estimate the fractal dimension both directly and indirectly by comparing the area-perimeter-scale relations. Based on scaling equations, a system was created for this operation. The conclusion is that all existing theories in tribology should be adapted to take into account fractal si...
IOP Conference Series: Materials Science and Engineering, 2020
The equipment of wastewater treatment plants is continuously subjected to different kinds of wear... more The equipment of wastewater treatment plants is continuously subjected to different kinds of wear, as corrosion, abrasion, cavitation, erosion etc. The most affected components are those of slurry pumps, the slurry producing intense abrasive wear. The service life of pumps (wear rings, sealing, bearings, impellers, and casings) can considerably be extended by proper coating. Before the implementation of a new coating in equipment, its friction and wear behaviour must be determined beside corrosion resistance. This paper presents the results of friction tests carried out on AMSLER machine. The tribological pair was composed by Al2O3 40TiO2 (AMDRY 6250) coating deposited on substrate of a pump shaft sleeve running against a rolling bearing steel disk in dry lubrication conditions. The experimental results are compared against those obtained for uncoated steel.
IOP Conference Series: Materials Science and Engineering, 2016
The ability of the antifriction materials to withstand with no lubrication for a while can be a s... more The ability of the antifriction materials to withstand with no lubrication for a while can be a solution for the catastrophic failure of automotive journal bearings from the internal combustion engines in accidental breakdown of the oil pump. A thick layer of antifriction material (babbit) was deposited by gravitational casting on a steel disk substrate. Four tribological disk samples coated with babbit are tested against a steel shoe on Amsler tribometer at different speeds and loads in dry friction. The values of the friction coefficient versus speed and load are presented, the obtained results indicating a mild wear regime, recommending the new babbit as a possible coating for the bushes of the journal bearings in automotive internal combustion engines. Further tests must be dedicated to the establishment of the wear intensity of the steel shoe - babbit disk tribological pair, both for motor oil lubricated and dry friction conditions.
Tribological properties of lithium potassium titanate (PT), molybdenum disulphide, and tungsten d... more Tribological properties of lithium potassium titanate (PT), molybdenum disulphide, and tungsten disulphide-dispersed mineral oil (MO) were investigated. The sample containing 2 wt.% WS2 exhibited the lowest coefficient of friction. However, the wear scar diameters of the additivated samples were very narrow. Extreme pressure properties of mineral oil were enhanced with the addition of additives. The rolling contact fatigue results exhibited better fatigue life of the balls in MoS2 and PT-dispersed MO. Surface characterization of the balls indicated more pitting on the balls of the MO and WS2-dispersed MO as compared to MoS2 and PT, indicating a stable film in the case of MoS2 and PT, which was confirmed by the presence of additives on ball surfaces by Raman spectrograph. The results of extended rolling contact fatigue tests proved that PT-added mineral oil provided the highest life cycles of the tested balls, followed by MoS2 and WS2-added mineral oil; thus, indicating PT as a plaus...
Limited work on the wear properties of martensitic stainless-steel weld clads initiated this work... more Limited work on the wear properties of martensitic stainless-steel weld clads initiated this work which included investigations on microstructural and wear properties of cladded AISI 410 (filler wire)/EN 8 plates (substrate). Three layers of martensitic stainless steel (AISI 410) were deposited using metal inert gas (MIG) welding on medium carbon steel (EN 8) achieving a 51.5 ± 2.35 HRC of top layer. The elemental and phase fractions of the cladded layers indicated 98% martensite phase and retained austenite (2%). About 40% dilution was observed between EN 8 and the first weld layer. The results of tests carried out on pin on disc tribometer revealed an enhancement of anti-wear life of the martensitic weld cladded EN 8 by three times that of uncladded EN 8. The uncladded EN 8 plate suffered severe damage and high wear, leading to its failure at 478 s. The failure of the uncladded EN 8 sample was identified by the occurrence of high vibration of the pin on disc tribometer which ultim...
Cardan joints are used in transmissions between misaligned shafts, as in all-wheel-drive (AWD) ca... more Cardan joints are used in transmissions between misaligned shafts, as in all-wheel-drive (AWD) cars and railway applications. Their functioning is accompanied by heavy cyclical loads, with the cardan cross spindles subjected to intensive abrasive wear and pitting. In this paper, a solution to the mentioned issue is proposed, thin anti-wear coatings of Metco 32 and Metco 72 metallic powders deposited by atmospheric plasma spray (APS) on cylindrical samples cut from spindles of two cardan crosses made of 40Cr10 and RUL2 steel. The morphological analysis of the coated surfaces was realized by scanning electron microscopy (SEM), and the elemental composition of the tested samples was elaborated by energy-dispersive X-ray spectroscopy (EDS). To investigate the wear resistance of the coated samples in dry and grease-lubricated conditions, tests at constant load and constant speed were carried out using an AMSLER tribometer. The results of greased tests proved that the expulsion of the lub...
IOP Conference Series: Materials Science and Engineering, 2020
This work investigates the friction reduction capability of dimple – textured steel surface creat... more This work investigates the friction reduction capability of dimple – textured steel surface created using a vertical milling machine. A suitable geometry for creation of dimples was chosen and cashew nut shell liquid (CNSL) was used as lubricant. A L9 orthogonal array was created using Taguchi design of experiment where load, speed of disc and duration of the test were chosen as the parameters. A pin – on – disc tribometer is used to find the coefficient of friction (COF) between an EN 24 steel pin and the dimple – textured steel disc made of low carbon steel. ASTM G99 standard was used for the test and the lubricant was supplied intermittently. Optimization was carried out using Taguchi method, where the optimized condition of the input parameters influenced a substantial change of 32.38% in COF as compared to the non – textured disc surface. The lubricant retention capacity of the dimple was the primary cause for the decrease in COF.
Journal of Materials Engineering and Performance, 2021
Hadfield steels are materials with high wear resistance used in the construction of parts that wo... more Hadfield steels are materials with high wear resistance used in the construction of parts that work in abrasive friction, high pressures and mechanical shock conditions. Four experimental samples, obtained from commercial T105Mn120 steel, were subjected to isothermal dynamic mechanical analysis in strain sweep mode (DMA-SS), by means of a dual cantilever specimen holder, at two temperatures, − 40 and + 50°C, with two SS frequencies: 0.5 and 16.66 Hz. These temperatures and frequencies correspond to the extreme conditions encountered during railway exploitation, being caused by environmental temperature or wagon wheel speed, respectively. The samples were work hardened through dynamic loadings and present different surface profilometries. Wear tests were carried out, and mean friction coefficient was determined based on friction torque measurements. Prior and after wear test, surface morphology was analyzed using scanning electron microscopy coupled with energy dispersive spectroscopy and micro-hardness determinations. The results indicate that the tested samples underwent work hardening through a wear mechanism that can explain the remarkable surface resistance of these executive elements of railway safety systems cast from Hadfield steel.
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2020
The current work aims to develop a biodegradable lubricant by adding different volume percentages... more The current work aims to develop a biodegradable lubricant by adding different volume percentages of cashew nut shell liquid (CNSL) in neat castor oil (NCO) and investigating its possibility as replacement to non-biodegradable mineral oil (commercial mineral oil) in industrial applications. The blend exhibiting better tribological properties was additived with different weight percentages of reduced graphene oxide (r-GO) nano-platelets and further tribological tests were performed. The performance of 40%CNSL+NCO was 45.8% better than commercial mineral oil, and with the addition of the 0.5% r-GO in the blend, the performance was improved by 61.7% than the commercial mineral oil. Finally, the novel biodegradable mixture blended with nanoparticles was employed as a lubricant in a gearbox, proving the superiority of the biodegradable lubricant over the commercial mineral oil.
IOP Conference Series: Materials Science and Engineering, 2020
In the last decades, mechanical engineering applications have extensive use in many subdomains. M... more In the last decades, mechanical engineering applications have extensive use in many subdomains. Many researchers have used Al2O3 40TiO2 (AMDRY6250) type coatings that have a wide use of plasma jets, significantly improving their wear, corrosion resistance and heat shock properties. It is especially used for hydraulic components such as pumps, impellers, and blowers. The performance of Al2O3 40TiO2 layer is conditioned by a number of technological parameters of deposition, powder granulation and deposition incidence angle. In the present study, the authors will make sequential depositions of Al2O3 40TiO2 on the surface of a material coming from a hydraulic system. Microstructural analysis of optical microscopy, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDAX) are performed both in the surface of the deposited material and in the section of the coated specimens, identifying the microstructure and the component phases. The authors highlighted the emergence ...
IOP Conference Series: Materials Science and Engineering, 2019
The pumping stations are key points of water treatment plants, their performance directly affecti... more The pumping stations are key points of water treatment plants, their performance directly affecting the serviceability of the entire water treatment system. The excessive wear of mechanical components conducts to pumping station out of service state. The deposition of thin coatings on the elements subjected to wear can generally extend the operating time of the water treatment plants. The paper analyses the failure modes of the mechanical components of the pumping stations and the existing efficient solutions for thin coating deposition to protect them from excessive wear. Consequently, an effective coating is deposited on the raw metal by Atmospheric Plasma Spraying (APS) and tribological tests are developed for an initial assessment of the anti-wear properties of the coating. The worn contact surfaces are analysed by Scanning Electron Microscopy (SEM) and the chemical composition is established by Energy-dispersive X-ray spectroscopy (EDS). The tests are still in development, reve...
The life of metal forming dies, and the efficiency of tooling industries depends on the mechanica... more The life of metal forming dies, and the efficiency of tooling industries depends on the mechanical and wear properties of tool steel. These properties can be further improved by depositing the ceramic coating on heat-treated tool steel. There are many coating materials available with numerous excellent properties. But problem is how to select the best coating material. Compared to various studies related to material selection problems in the contrasting area of utilization, remarkably, few research work is done in tooling industries. In the present work, we have identified eight coating materials (alternatives) and nine evaluation criteria under the consultation of an expert in the tooling application and tribological field. To deal with this coating material selection problem, an integrated fuzzy-MADM method is proposed comprising BWM and fuzzy-MARCOS. This integrated fuzzy-MADM method is used to evaluate the alternative, and the obtained results are scrutinized under extensive use...
Bulletin of the Polytechnic Institute of Iași. Machine constructions Section
Technologies such additive manufacturing are slowly becoming more and more present on the market,... more Technologies such additive manufacturing are slowly becoming more and more present on the market, covering different areas of the industry due to its great potential. Even so, there are still many aspects which are unexplored or which can be improved. One of them being the study of the tribological proprieties for all these parts, which are produced through additive manufacturing methods, such as powder bed fusion, binder jetting, direct energy deposition, fused filament fabrication, material jetting, vat photopolymerization, and sheet lamination. The scope of this paper is to bring together the tribological proprieties for the 3D printed parts, and to have a critical analysis of these proprieties, in order to easily decide which printing method is suitable, depending of the working conditions of the printed component. In addition, this paper will describe the working principle for each technology, and the type of materials that are commonly used in the printing process. Depending o...
The use of biomass mixtures as a feedstock in the production of pellets requires optimization of ... more The use of biomass mixtures as a feedstock in the production of pellets requires optimization of the percentages of the components, since interactions occur during combustion between the components forming the blend (lignin, cellulose, and hemicellulose), affecting characteristics of pellets such as calorific value, ash content, fine fraction content, bulk density, and mechanical durability. Our study focuses on the assessment of the quality of pellets produced from biomass blends generated from pruning seabuckthorn and blackberry mixed with wheat straw. The results of literature data analysis and laboratory research show that wheat straw pellets exhibited the lowest calorific value (15.2 ± 0.2 MJ/Kg) and the highest ash content (5.7 ± 0.18%) while seabuckthorn and blackberry biomass pellets possessed significantly higher calorific value with low ash content. According to the maximization of the mixtures taken in the study, it was proved that the addition of up to 25% wheat straw re...
Shape Memory Alloys (SMA) have been researched extensively in the past forty years. The different... more Shape Memory Alloys (SMA) have been researched extensively in the past forty years. The different available compositions of these alloys can make them suitable for certain applications with specific requirements. The increasing demand for high precision machinery and equipment brought forward the need to search for alloys that that can perform better under stress than conventional materials. This is the case of Shape Memory Alloys. As their name suggests, these alloys can regain their initial shape after being subjected to external stresses, up to a specific degree. Due to the research carried out over the past two decades on these alloys, they became better known and more accessible, being tested in order to be integrated in various applications. One such application consists of using a shape memory alloy formed into disc springs in order to optimize the preloading of angular contact ball bearings. The tests were conducted using a device especially developed for this research, with the purpose of recording the friction torque evolution and the preload induced by disc springs during the operation of the rolling bearings in order to assess the possibility of using elastic elements for active ball bearings preloading systems.
IOP Conference Series: Materials Science and Engineering
Technology based on additive manufacturing is rapidly emerging and is being used in a wide range ... more Technology based on additive manufacturing is rapidly emerging and is being used in a wide range of industries. Meeting the precision and accuracy (P&A) requirements of 3D printed parts (shape and size tolerances, surface quality, etc.) is increasingly becoming an issue. This paper presents a critical analysis of the tribological problems encountered in 3D printing for parts manufactured through different types of technologies, such as powder bed fusion, binder jetting, direct energy deposition, material jetting, fused filament fabrication, vat photopolymerization, sheet lamination, and ultrasonic consolidation. For all these additive manufacturing technologies, this paper will present a brief description, classification, examples of materials used, and tribological problems of the obtained machine parts.
IOP Conference Series: Materials Science and Engineering, 2020
Reliability and maintenance play an important role in the field of rail vehicle systems. In order... more Reliability and maintenance play an important role in the field of rail vehicle systems. In order to be reliable, this type of transport needs continuous monitoring and regular maintenance. Regarding requested repair and maintenance interventions in relation to the probability of failure for each component, assembly or subassembly, additional information could be taken by data acquisition from sensors fitted to the locomotive bogies. The influence of the rail pattern configuration and the asymmetry of the positioning of both the traction motors and the gearbox on the amplitude and frequency of the introduced vibrations is considered. Fast and robust online signal processing algorithms are essential for designing a smart device. In this way, maintenance models can be created based on the state of the systems and integrated platforms can be produced in order to improve the diagnosis and expertise of a maintenance program. The paper presents the method of determining the vibrations ind...
Bulletin of the Polytechnic Institute of Iași. Machine constructions Section
Fractals and chaos theory provide means of modeling dynamic changes in micro and nano topography ... more Fractals and chaos theory provide means of modeling dynamic changes in micro and nano topography on friction surfaces caused by various tribological mechanisms and processes. Friction and wear phenomena in tribological systems can be interpreted on a macroscopic scale. With the development of miniaturized scale and nanoscale systems, it has been launched the hypothesis that macro-level systems cannot reflect the microscale and nanoscale phenomena. A conclusive case is given by the calculation of frictional torque in microscale orientation, in this situation being found that models created by bearing producers cannot validate experimental results. By applying the “box-counting” method, it is possible to estimate the fractal dimension both directly and indirectly by comparing the area-perimeter-scale relations. Based on scaling equations, a system was created for this operation. The conclusion is that all existing theories in tribology should be adapted to take into account fractal si...
IOP Conference Series: Materials Science and Engineering, 2020
The equipment of wastewater treatment plants is continuously subjected to different kinds of wear... more The equipment of wastewater treatment plants is continuously subjected to different kinds of wear, as corrosion, abrasion, cavitation, erosion etc. The most affected components are those of slurry pumps, the slurry producing intense abrasive wear. The service life of pumps (wear rings, sealing, bearings, impellers, and casings) can considerably be extended by proper coating. Before the implementation of a new coating in equipment, its friction and wear behaviour must be determined beside corrosion resistance. This paper presents the results of friction tests carried out on AMSLER machine. The tribological pair was composed by Al2O3 40TiO2 (AMDRY 6250) coating deposited on substrate of a pump shaft sleeve running against a rolling bearing steel disk in dry lubrication conditions. The experimental results are compared against those obtained for uncoated steel.
IOP Conference Series: Materials Science and Engineering, 2016
The ability of the antifriction materials to withstand with no lubrication for a while can be a s... more The ability of the antifriction materials to withstand with no lubrication for a while can be a solution for the catastrophic failure of automotive journal bearings from the internal combustion engines in accidental breakdown of the oil pump. A thick layer of antifriction material (babbit) was deposited by gravitational casting on a steel disk substrate. Four tribological disk samples coated with babbit are tested against a steel shoe on Amsler tribometer at different speeds and loads in dry friction. The values of the friction coefficient versus speed and load are presented, the obtained results indicating a mild wear regime, recommending the new babbit as a possible coating for the bushes of the journal bearings in automotive internal combustion engines. Further tests must be dedicated to the establishment of the wear intensity of the steel shoe - babbit disk tribological pair, both for motor oil lubricated and dry friction conditions.
Tribological properties of lithium potassium titanate (PT), molybdenum disulphide, and tungsten d... more Tribological properties of lithium potassium titanate (PT), molybdenum disulphide, and tungsten disulphide-dispersed mineral oil (MO) were investigated. The sample containing 2 wt.% WS2 exhibited the lowest coefficient of friction. However, the wear scar diameters of the additivated samples were very narrow. Extreme pressure properties of mineral oil were enhanced with the addition of additives. The rolling contact fatigue results exhibited better fatigue life of the balls in MoS2 and PT-dispersed MO. Surface characterization of the balls indicated more pitting on the balls of the MO and WS2-dispersed MO as compared to MoS2 and PT, indicating a stable film in the case of MoS2 and PT, which was confirmed by the presence of additives on ball surfaces by Raman spectrograph. The results of extended rolling contact fatigue tests proved that PT-added mineral oil provided the highest life cycles of the tested balls, followed by MoS2 and WS2-added mineral oil; thus, indicating PT as a plaus...
Limited work on the wear properties of martensitic stainless-steel weld clads initiated this work... more Limited work on the wear properties of martensitic stainless-steel weld clads initiated this work which included investigations on microstructural and wear properties of cladded AISI 410 (filler wire)/EN 8 plates (substrate). Three layers of martensitic stainless steel (AISI 410) were deposited using metal inert gas (MIG) welding on medium carbon steel (EN 8) achieving a 51.5 ± 2.35 HRC of top layer. The elemental and phase fractions of the cladded layers indicated 98% martensite phase and retained austenite (2%). About 40% dilution was observed between EN 8 and the first weld layer. The results of tests carried out on pin on disc tribometer revealed an enhancement of anti-wear life of the martensitic weld cladded EN 8 by three times that of uncladded EN 8. The uncladded EN 8 plate suffered severe damage and high wear, leading to its failure at 478 s. The failure of the uncladded EN 8 sample was identified by the occurrence of high vibration of the pin on disc tribometer which ultim...
Cardan joints are used in transmissions between misaligned shafts, as in all-wheel-drive (AWD) ca... more Cardan joints are used in transmissions between misaligned shafts, as in all-wheel-drive (AWD) cars and railway applications. Their functioning is accompanied by heavy cyclical loads, with the cardan cross spindles subjected to intensive abrasive wear and pitting. In this paper, a solution to the mentioned issue is proposed, thin anti-wear coatings of Metco 32 and Metco 72 metallic powders deposited by atmospheric plasma spray (APS) on cylindrical samples cut from spindles of two cardan crosses made of 40Cr10 and RUL2 steel. The morphological analysis of the coated surfaces was realized by scanning electron microscopy (SEM), and the elemental composition of the tested samples was elaborated by energy-dispersive X-ray spectroscopy (EDS). To investigate the wear resistance of the coated samples in dry and grease-lubricated conditions, tests at constant load and constant speed were carried out using an AMSLER tribometer. The results of greased tests proved that the expulsion of the lub...
IOP Conference Series: Materials Science and Engineering, 2020
This work investigates the friction reduction capability of dimple – textured steel surface creat... more This work investigates the friction reduction capability of dimple – textured steel surface created using a vertical milling machine. A suitable geometry for creation of dimples was chosen and cashew nut shell liquid (CNSL) was used as lubricant. A L9 orthogonal array was created using Taguchi design of experiment where load, speed of disc and duration of the test were chosen as the parameters. A pin – on – disc tribometer is used to find the coefficient of friction (COF) between an EN 24 steel pin and the dimple – textured steel disc made of low carbon steel. ASTM G99 standard was used for the test and the lubricant was supplied intermittently. Optimization was carried out using Taguchi method, where the optimized condition of the input parameters influenced a substantial change of 32.38% in COF as compared to the non – textured disc surface. The lubricant retention capacity of the dimple was the primary cause for the decrease in COF.
Journal of Materials Engineering and Performance, 2021
Hadfield steels are materials with high wear resistance used in the construction of parts that wo... more Hadfield steels are materials with high wear resistance used in the construction of parts that work in abrasive friction, high pressures and mechanical shock conditions. Four experimental samples, obtained from commercial T105Mn120 steel, were subjected to isothermal dynamic mechanical analysis in strain sweep mode (DMA-SS), by means of a dual cantilever specimen holder, at two temperatures, − 40 and + 50°C, with two SS frequencies: 0.5 and 16.66 Hz. These temperatures and frequencies correspond to the extreme conditions encountered during railway exploitation, being caused by environmental temperature or wagon wheel speed, respectively. The samples were work hardened through dynamic loadings and present different surface profilometries. Wear tests were carried out, and mean friction coefficient was determined based on friction torque measurements. Prior and after wear test, surface morphology was analyzed using scanning electron microscopy coupled with energy dispersive spectroscopy and micro-hardness determinations. The results indicate that the tested samples underwent work hardening through a wear mechanism that can explain the remarkable surface resistance of these executive elements of railway safety systems cast from Hadfield steel.
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2020
The current work aims to develop a biodegradable lubricant by adding different volume percentages... more The current work aims to develop a biodegradable lubricant by adding different volume percentages of cashew nut shell liquid (CNSL) in neat castor oil (NCO) and investigating its possibility as replacement to non-biodegradable mineral oil (commercial mineral oil) in industrial applications. The blend exhibiting better tribological properties was additived with different weight percentages of reduced graphene oxide (r-GO) nano-platelets and further tribological tests were performed. The performance of 40%CNSL+NCO was 45.8% better than commercial mineral oil, and with the addition of the 0.5% r-GO in the blend, the performance was improved by 61.7% than the commercial mineral oil. Finally, the novel biodegradable mixture blended with nanoparticles was employed as a lubricant in a gearbox, proving the superiority of the biodegradable lubricant over the commercial mineral oil.
IOP Conference Series: Materials Science and Engineering, 2020
In the last decades, mechanical engineering applications have extensive use in many subdomains. M... more In the last decades, mechanical engineering applications have extensive use in many subdomains. Many researchers have used Al2O3 40TiO2 (AMDRY6250) type coatings that have a wide use of plasma jets, significantly improving their wear, corrosion resistance and heat shock properties. It is especially used for hydraulic components such as pumps, impellers, and blowers. The performance of Al2O3 40TiO2 layer is conditioned by a number of technological parameters of deposition, powder granulation and deposition incidence angle. In the present study, the authors will make sequential depositions of Al2O3 40TiO2 on the surface of a material coming from a hydraulic system. Microstructural analysis of optical microscopy, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDAX) are performed both in the surface of the deposited material and in the section of the coated specimens, identifying the microstructure and the component phases. The authors highlighted the emergence ...
IOP Conference Series: Materials Science and Engineering, 2019
The pumping stations are key points of water treatment plants, their performance directly affecti... more The pumping stations are key points of water treatment plants, their performance directly affecting the serviceability of the entire water treatment system. The excessive wear of mechanical components conducts to pumping station out of service state. The deposition of thin coatings on the elements subjected to wear can generally extend the operating time of the water treatment plants. The paper analyses the failure modes of the mechanical components of the pumping stations and the existing efficient solutions for thin coating deposition to protect them from excessive wear. Consequently, an effective coating is deposited on the raw metal by Atmospheric Plasma Spraying (APS) and tribological tests are developed for an initial assessment of the anti-wear properties of the coating. The worn contact surfaces are analysed by Scanning Electron Microscopy (SEM) and the chemical composition is established by Energy-dispersive X-ray spectroscopy (EDS). The tests are still in development, reve...
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