Performance In Terms Of Wear Research Articles

Optimization of heavy haul railway wheel profile based on rolling contact fatigue and wear performance

This paper presents a methodology to develop optimal railway wheel profiles based on their rolling contact fatigue (RCF) and wear performance. The NSGA-II multi-objective optimization algorithm was employed to minimize two objective functions: the wear index and the fatigue index while satisfying objective constraints. The commercial multibody software SIMPACK® was used for modeling the railway vehicle's dynamics and macrogeometry of a Brazilian heavy haul railway. The objective functions and constraints are obtained from the dynamic simulation and used as inputs to the optimization algorithm which then provides new wheel profiles as the output. To verify the long-term performance of the new profiles, wear and fatigue analysis were performed. Wear simulation using Archard's law generated worn profiles that were used to estimate the wheel's theoretical service life and degradation rate. Fatigue simulation employing the Dang Van fatigue criterion was done to obtain the stress histories for fatigue analysis using a Finite Element Model (FEM) inside ANSYS® software. The study resulted in three optimized profiles. The first was optimal for wear, the second was optimal for fatigue, and the last presented an intermediate performance in terms of wear and fatigue. The findings show that all three optimized wear profiles reduced the wear index by at least 47% when compared to the currently used profile. Furthermore, an improvement of at least 159% was observed in the fatigue index for all new profiles. The service life increased 12% according to the current hollow wheel criterion, 3 mm.

Wear assessment of a Ti–6Al–4V motion-preserving porous artificial-cervical-joint fabricated by SLM after surface carburization

Adjacent segment degenerative diseases are a major clinical concern for anterior cervical corpectomy with fusion surgery. In this study, a hybrid motion-preserving cervical prosthesis consists of two articulating joints and one porous fusion body is designed to provide motion ability and reduce the occurrence of degenerative diseases. The hybrid design is fabricated from Ti–6Al–4V (TC4) alloy using selective laser melting (SLM) technology. After carburization pretreatment, two types of bearing couple SLM-TC4 self-mating and SLM-TC4/UHMWPE were studied in terms of lubrication regime, contact mechanics and wear performance. According to the ISO 18192-1 standard, five million cycles (Mc) of in vitro spine simulator wear tests were conducted in bovine serum lubricated condition.Hamrock-Dawson minimum lubrication film thickness analysis stated that both bearing was likely under boundary lubrication only, with extensive surface asperities contact. And, the contact stress encountered during in vitro condition was not enough to cause surface fatigue failure of any bearing couple. In term of wear performance, the obtained steady state wear rates were 0.160 ± 0.004 mm3/Mc for SLM-TC4 self-mating and 8.57 ± 0.06 mm3/Mc for SLM-TC4/UHMWPE bearing couples, respectively. According to these outcomes, SLM-TC4 self-mating couple was more promising for the articulating joint bearing design.For SLM-TC4 self-mating couple, the initial wear mechanism was abrasion with potential third-body abrasion wear. As the wear cycle proceeding, the TiC cermet layer was gradually damaged and exposed the local bare metal. Under this circumstance, material loss was consisted of abrasion wear, adhesion wear, and tribo-corrosion. In comparison, the wear mechanism of SLM-TC4/UHMWPE bearing was always abrasion-adhesion of UHMWPE. The surface of UHMWPE socket was severely plowed by the hard micro bulge of the TiC layer, and material loss and plastic deformation occurred only on the UHMWPE socket. In conclusion, carburization pre-treatment causes a hard TiC cermet layer formation on the SLM-TC4, which enhance its hardness and protect underling material from corrosion damage. The thickness and quality of the TiC layer directly affect the longevity of the joint prosthesis in vivo.

Pravci razvoja i primene plazma nitriranja u industriji

This paper presents a discussion of the results of previous research of the effects of surface modification of structural materials and tool steels using plasma nitriding (PN) in order to improve their mechanical, tribological and corrosion behavior. The paper discusses the current status and future directions in the application of PN on various wearing components that are exposed to high loads, stresses and frequent temperature changes. The paper provides an overview of the relevant literature whose results show the most favorable or optimal parameters of the PN process aimed at achieving the best performance in terms of wear and corrosion resistance and hardness increase for the various materials considered. Systematization of literature data about research of the impact of low-temperature PN on stainless steels has placed emphasis on those process mechanisms that achieve benefits for surface layers without creating negative side effects in the form of loss of corrosion resistance. The strengthening of hot forging dies is considered through the reasons and problems that cause the need for the application of PN, and then paper focuses on the role of PN in achieving the tribological properties required to extend the service life of the die. Publications in which the nitriding of titanium alloys is investigated through the reduction of wear, increase of bearing capacity and microhardness depending on the input parameters of the process, ie the optimal parameters applied in order to obtain the best performance characteristics are cited. The application of PN to aluminum and its alloys is discussed, as well as the conditions of testing and the achieved improvements.

Knee Wear Assessment: 3D Scanners Used as a Consolidated Procedure.

It is well known that wear occurring in polyethylene menisci is a significant clinical problem. At this regard, wear tests on biomaterials medical devices are performed in order to assess their pre-clinical performance in terms of wear, durability, resistance to fatigue, etc. The objective of this study was to assess the wear of mobile total knee polyethylene inserts after an in vitro wear test. In particular, the wear behavior of mobile bearing polyethylene knee configurations was investigated using a knee joint wear simulator. After the completion of the wear test, the polyethylene mobile menisci were analyzed through a consolidated procedure by using 3D optical scanners, in order to evaluate the 3D wear distribution on the prosthesis surface, wear depths, wear rates, amount of material loss and contact areas. The results in terms of wear rates and wear volumes were compared with results of gravimetric tests, finding equivalent achievements.

Effect of Alloy Content in Hardox450 + FeW Composites Alloyed by PTAW on Wear Characteristic

In this study, Hardox450 + FeW alloys were coated on AISI1020 substrate material by using plasma transferred arc welding (PTAW) technique. The ratios of the coating materials were chosen as 5, 10, 15, 20 and 25 wt % FeW. The coating process was carried out as the current density (130 A), shielding gas (pure argon), shielding gas flow rate (25 L min–1), plasma gas flow rate (0.8 l min–1), welding speed (0.01 m min–1) and electrode diameter (3.2 mm). The coated alloys were characterized by optical microscope (OM), Scanning electron microscope (SEM), Elemental mapping, Energy dispersive spectrometer (EDS) and X-Ray diffractometer (XRD). Moreover, microhardness and wear tests were applied to determine the mechanical behavior. After wear test, wear rates were calculated by the mass losses of the specimens. The morphologies of worn surfaces were evaluated by SEM. Hardox450 + 25 wt % FeW showed the most combination in terms of wear performance with lower wear values under high-stress wear.

Flank wear and rake wear studies for arc enhanced HiPIMS coated AlTiN tools during high speed machining of nickel-based superalloy

Several studies are available on wear behaviour of the physical vapour deposited as well as chemical vapour deposited coated cutting tools during continuous cutting operations. However, there still exists deficiency in a comprehensive analysis of the dominating wear mechanisms. The present study investigates the wear behaviour of the AlTiN coating on the cemented carbide developed by novel arc enhanced high impulse magnetron sputtering technique (HiPIMS). In this study, micro abrasive blasting (MAB) has been adopted as a surface modification as well as the coating treatment technique. This was done primarily to enhance the performance of the cutting tool by altering the surface and sub-surface properties so that a comparison can be made with only conventionally coated and uncoated tools in terms of wear performance. In order to study the tool wear behaviour, aerospace material Nimonic C 263, possessing high strength owing to the presence of the metallic carbides and work hardening properties, was selected as workpiece material for longitudinal turning. The process parameters such as feed, depth of cut and cutting speed were kept constant to 0.12 mm/rev, 1 mm and 60 m/min respectively. Scanning electron microscopy (SEM) was carried out for detailed investigation of the worn-out regions at the rake and flank faces while energy dispersive X-ray spectroscopy (EDX) was utilized for observing the variation in elemental composition during machining. Diffusion wear studies were carried out under dynamic condition by cutting the cross-section of the worn-out inserts after the machining operation for both uncoated and coated samples, while diffusion under static condition was carried out by coupling the workpiece and tool and then heating at varying temperature. The results indicate the efficacy of the MAB as a surface treatment technique for improving the wear performance of the cutting tools during the machining of the nickel-based superalloy.

Influence of Steel Substrate on the Properties of PACVD Gradient Multilayer TiCN Coating

Abstract Titanium-based hard coatings are known for increasing both hot work and cold work tool steel performance in terms of wear and corrosion resistance. In this paper, the influence of different steel substrates on the properties of plasma-assisted chemical vapor deposition (PACVD) gradient multilayer titanium carbo-nitride (TiCN) coating was investigated. The same gradient multilayer TiCN coating was deposited by pulsed direct current (dc) PACVD on a hot work tool steel grade X37CrMoV5-1 and two Böhler cold work tool steels K390 PM and K110. Hardened samples of each steel were also included in the investigation. The coating-substrate systems have been characterized with respect to their chemical composition, thickness, adhesion, and resistance to electrochemical corrosion, abrasion, erosion, and dry sliding wear. The results show an increased wear and corrosion resistance of TiCN-coated specimens compared with noncoated and prehardened specimens. The application of gradient multilayer TiCN coating on different steel substrates shows the different behavior of TiCN coating. Therefore, besides the coating itself, the base material on which the coating is applied has a significant influence on the tool properties.

Wear behavior of the plasma and thermal oxidized Ti-15Mo and Ti-6Al-4V alloys

Titanium and its alloys widely used in load bearing applications. Titanium alloys are capable of providing lower elastic modulus and better corrosion resistance with alloying processes. In spite of the modified mechanical properties, the surface degradation is still the main critical defect. Ti-15Mo alloy is one of the alpa+beta titanium alloys with acceptable mechanical and chemical superiority. Recent researches in literature show that the wear performance of base Ti-15Mo is relatively low as compared to Ti-6Al-4V, using in high performance applications. Plasma oxidized surfaces increase the tribological and chemical performance of titanium alloys. In this study the Ti-15Mo alloy and Ti-6Al-4V alloys were compared in terms of wear performance. To obtain alloys with similar microstructure they were solution treated at 800°C 1H and then air-cooled. The plasma and thermal oxidations were applied at 650°C for 1 hour. Wear performance of oxidized surfaces investigated in dry conditions. Oxidized surface characterized with XRD, SEM, 3D profilometer and hardness measurements. Wear volume calculated with 3D profilometer. Results show that oxidizing increased the surface roughness and improved the wear performance of Ti15Mo alloy. The plasma and thermal oxidized Ti-15Mo showed a remarkable increase in wear resistance.

Investigation of the lubricated wear behavior of ductile cast iron and quenched and tempered alloy steel for possible use in worm gearing

Bronze-on-steel couples are commonly used in worm gearing, but alternative material combinations may provide better performance in terms of wear. Lubricated rolling–sliding tests were therefore carried out on GJS700 nodular cast iron and 42CrMo4V quenched and tempered steel. The tests were performed in the disk-on-disk configuration with the applied load, rolling–sliding ratio and lubrication selected to simulate ‘in-service’ severe working conditions. The tests were periodically interrupted to measure weight loss and to inspect the surface condition. At the end of the test the wear damage was studied by means of metallographic observations of the worn surfaces and the subsurface regions. Pitting damage was observed to evolve differently in the steel and cast iron specimens. Both the lubrication condition and the materials microstructure showed a strong effect on crack initiation and propagation. They influenced crack inclination and branching that resulted in the formation of pitting and spalling craters.

The Effect of Tribology Behavior on Machining Performances When Using Bio-based Lubricant as a Sustainable Metalworking Fluid

Metalworking fluid (MWF) is commonly used to reduce wear and friction, thus improve the machining productivity and quality. However, the usage of conventional MWF made from mineral oil causes negative effects to the ecology and human health. Therefore, it is desirable to formulate a sustainable MWFs as an alternative to petroleum-based oils. The crude jatropha oil was chemically altered via transesterification process of jatropha methyl ester and trimethylolpropane to develop various compositions of modified jatropha oils (MJOs). The orthogonal cutting process was carried out and the lubricants were supplied by using minimum quantity lubrication (MQL) technique. It was observed that the MJO5 exhibits an outstanding performance in terms of wear and friction as well as cutting force and maximum cutting temperature when compared to commercial synthetic ester (SE). This works shows that MJO5 is a viable candidate to replace SE as a machining lubricant.

Development and protection evaluation of two new, advanced ceramic composite thermal spray coatings, Al2O3–40TiO2 and Cr3C2–20NiCr on carbon steel petroleum oil piping

Carbon steel is the most commonly used material in the petroleum industry owing to its high performance and relatively low cost compared with highly alloyed materials. The corrosion resistance of carbon steel in aqueous solutions is dependent on the surface layer created on carbon steel. This layer often consists of siderite (FeCO3) and cementite (Fe3C), but it is neither compact nor dense. To improve the carbon steel surface resistance against corrosion and wear, a compact and dense layer can be deposited onto the surface by thermal spray coating. In this research, Al2O3–40TiO2 and Cr3C2–20NiCr were deposited onto mechanical part surfaces by HVOF spray technique. The present study describes and compares the electrochemical behavior of carbon steel, Cr3C2–20NiCr and Al2O3–40TiO2 in 3.5% NaCl using open-circuit potential measurement (OCP) and electrochemical impedance microscopy (EIS) for 36 days. The tribological and mechanical properties are also investigated using a tribometer (pin-on-disc). The results indicate that these chemical composition coatings facilitated significant anti-corrosion and anti-wear improvement. However, the samples coated with Al2O3–40TiO2 exhibited the lowest corrosion rate. In terms of wear performance, both coated samples displayed similar behavior under different loads. Scanning electron microscopy (SEM) showed the distinctive microstructure of the HVOF-sprayed samples before and after corrosion and wear testing.

Tribological Performance of Aligned Silicon Nitride Ceramics under Isooctane‐Lubricated Oscillating Sliding Conditions

Silicon nitride (Si3N4) materials with preferentially aligned β‐Si3N4 grains were tribologically characterized with respect to their possible application in a high‐pressure gasoline pump. Tribological tests were performed under oscillating sliding conditions lubricated with isooctane as a substitute for gasoline using Si3N4 counterbodies. Performance in terms of wear of the aligned materials surpassed that of nonaligned reference Si3N4, as well as that of self‐mated silicon carbide, zirconia, alumina, and a steel sliding pair. The plane perpendicular to the extruding direction and parallel to the hot‐pressing axis was the most wear resistant.

Wear behaviour of carbon steel cutting wheel thermal flame sprayed with chromium carbide

Purpose – This study aims to develop and evaluate an inexpensive and durable metal cutting wheel using thermal spraying and polymer binding to enhance the wheel’s cutting capability by bonding hard particles (abrasives) onto the wheel. Design/methodology/approach – Thermal spraying was used to deposit the coating powder (chromium and silicon carbide) onto high carbon substrate. Wear loss and depth of cut as function of load, time and speed were evaluated on uncoated and coated wheel. Findings – The coated cutting wheel performed better than the uncoated cutting wheel in terms of wear performance. However, the coated cutting wheel experienced coating peel off at higher load and cutting speed, leading to a decrease in wear resistance of the cutting wheel. Thus, optimally cutting should be performed either at low cutting speed and high load or at high cutting speed and low load to prolong the wheel’s lifetime. Originality/value – The outcome of the study will be beneficial for academicians and industrial working on cutting wheel process.

Wear and friction behaviour of poly-ether-ether-ketone (PEEK) filled with graphene, WS2 and CNT nanoparticles

High-performance polymers show a great potential to replace machined metal components in a wide variety of applications owing to their promising mechanical, thermal and tribological properties. However, further improvements in their properties are still needed. The aim of this study was to evaluate and compare the effect of the material type and the morphology of well-known solid lubricant nanoparticles on the tribological properties of poly-ether-ether-ketone (PEEK) composites. Different nanoparticles were added to the PEEK matrix: WS2 fullerene-like (WS2F), WS2 needle-like (WS2N), carbon nanotubes (CNT) and graphene nanopowder (GNP). The results of dry-sliding tribological tests show that the material and the morphology of the nanoparticles have a crucial effect on both the wear and the coefficient of friction, primarily by affecting their macroscopic hardness, as well as the thickness and the surface coverage of their transfer films. The WS2-based nanoparticles outperformed the carbon-based nanoparticles in terms of wear performance; compared to PEEK, WS2F improved the wear rate by 10% and the WS2N by 60%, while the carbon-based particles deteriorated the wear behaviour by 20% (CNT) and as much as three times in the case of the GNP. The addition of WS2F nanoparticles and the CNT resulted in a lower coefficient of friction compared to the WS2N particles and the GNP.

Topography changes observation during running-in of rolling contacts

The automotive industry and the design of engines are strongly ruled by performance and legislation demands. In the valve train, besides the main function (transformation of rotation to translation movements) to fulfill, new requirements in environmental demands and performance in terms of wear are leading to more and more detailed studies of the cams and rollers. Wear reduction studies for prolonging lifetime of these components require decreasing the scale of observation down to roughness. Among the different wear stages of a component, the running-in is a crucial period which will greatly influence the lifetime and performance of components. The aim of this paper is to analyze the topography variations observed during the running-in of a camshaft on a valve train rig test. A truck engine׳s camshaft is run under realistic conditions and 3D surfaces are measured before and after the test by using relocation techniques. By measuring the very same surfaces before and after the experiment, a deep analysis of the running-in effects on surfaces can be performed. 3D surface roughness parameters are used in parallel with new proposed methods of analysis. As a result, the mechanisms involved during running-in are emphasized and can be used for further simulations and optimization of the cam roller contact.

Mechanical andTribological Characterization of Short Fibers Reinforced Polymer Composites

Solid particle erosion of polymer composites is a complex surface damage process, strongly affected by material properties and operational conditions. The present research work is undertaken to study the development, characterization and erosion wear performance of two different categories of fibers when reinforced in polymers. One of the two fiber is well known synthetic fiber i.e. glass fiber which is commercially used by many industries and the other fiber will be a natural fiber i.e. banana fiber which will be the new attempt in the present investigation. In both the above cases matrix material will remain epoxy. Attempts have been made to explore the possible use of a natural fiber as filler material in composites. To make an assessment of their (banana fiber) reinforcing potential in terms of wear performance and mechanical properties, various physical, mechanical and wear performance of the composites are studied in details and its comparison with a similar set of composites with glass fiber as a filler material is reported. The reported data are purely extracted from experimental measurement under controlled laboratory conditions. From the performed experiments it can be seen that a banana fiber can successfully replace the glass fiber as far as wear performance in concerned, as the study indicates that erosion wear performance of banana fiber based composites is better than that of the glass fiber reinforced composites. Banana fiber is also having a very low specific gravity, so their composites show very low density as compared to glass fiber reinforced composites. From other mechanical characterization it can be said that, in strength point of view, banana fiber-epoxy composites are not very much behind its counterparts glass fiber-epoxy composites.

향상된 폴리우레탄 기반 자기유변탄성체의 마찰 마모 특성연구

Typical magneto-rheological (MR) elastomers consist of silicon-based material. A number of studies have been carried out to evaluate the vibration and tribological characteristics of silicon-based MR e-lastomers. However, these elastomers have quite low strength, so they have low wear resistance. In this study, polyurethane-based MR elastomers with performances better than those of MR elastomers. Experiments have been conducted on different MR elastomers (Pu MR elastomer, Pu-Si MR elastomer, and Pu-wrapped-Si MR elastomer) and different predefined magnetic directions (Non-Direction, Vertical Direction, and Horizontal Directionality) to evaluate the friction and wear performance under a magnetic field. The results show that Pu-wrapped-Si MR elastomer with a horizontal predefined magnetic field has the best performance in terms of wear.

Effect of Bio-Lubricant and Biodiesel-Contaminated Lubricant on Tribological Behavior of Cylinder Liner–Piston Ring Combination

This article addresses the issue of friction and wear characteristics of diesel engine cylinder liner–piston ring combinations under different lubricating conditions using a pin-on-disc wear tribometer. The discs were made out of actual engine cylinder liner material using a casting process. Pins were made out of top compression ring material. The tests were conducted on a pin-on-disc tribometer for wear and friction characteristics of the cylinder liner and piston ring combination with diesel-contaminated rapeseed oil–based bio-lubricant, diesel-contaminated commercial synthetic lubrication oil (SAE 20W40), biodiesel-contaminated commercial synthetic lubrication oil (SAE 20W40), and used (150 h) commercial synthetic lubrication oil (SAE 20W40). Experimental results demonstrated that the rapeseed oil–based bio-lubricant and biodiesel-contaminated synthetic lubricant exhibited better performance in terms of wear, friction, and frictional force under similar operating conditions. Thus, usage of newly formulated bio-lubricant and biodiesel in the long run may have a positive impact on engine life.

A comparison of the abrasive wear behaviour of iron-chromium based hardfaced coatings deposited by SMAW and electric arc spraying

The abrasive wear behaviour of shielded metal arc welding (SMAW) hardfaced Fe–Cr–C deposits used in the sugar cane industry have been compared with an experimental arc-sprayed Fe–Cr–B coating. The aim was to identify an alternative process that performed equally or better than SMAW in terms of wear performance under a specific wear environment. The study showed that variations in the morphology of the carbides and structure of the weld deposits produced marked differences in resisting dry abrasive wear. The arc-sprayed coating exhibited comparable wear resistance to that of the SMAW overlays, although it had higher porosity and its microhardness was lower than the welded deposits.

Friction and wear performance of HFCVD nanocrystalline diamond coated silicon nitride ceramics

Silicon nitride (Si 3N 4) ceramics were selected as substrates due to their thermal and chemical compatibility to diamond that ensure the adequate NCD adhesion for mechanical purposes. NCD deposition was performed by hot-filament chemical vapour method (HFCVD) using Ar/H 2/CH 4 gas mixtures. The tribological assessment of homologous pairs of NCD films was accomplished using reciprocating ball-on-flat tests using NCD coated Si 3N 4 plates and balls. The friction evolution is characterized by an initial running-in regime with a sharp peak up to 0.7, shortly followed by a steady-state regime identified by very low friction coefficients values (0.02–0.03). The threshold load prior to delamination depends on the starting surface roughness of the substrates and attains a value of ∼ 40 N. In terms of wear performance, the NCD films reveal a mild wear regime ( K ∼ 10 − 7 mm 3 N − 1 m − 1 ) for self-mated dry sliding conditions.