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Aluminum alloys are widely used in various industries due to their as low density, high strength-to-weight ratio, and good corrosion resistance. However, their wear resistance is often inadequate for certain applications. Utilization of industrial waste materials, such as iron slag, as reinforcement in aluminum alloy matrix composites offers a sustainable approach to material development and waste management. The utilization of industrial waste materials for aluminum alloy matrix composite fabrication offers a waste utilization to material development. The loading of this reinforcement varied from 0 to 15 wt.% and different particle size range (220-140, 140-70, and 70-0 µm). A microscopic analysis indicated that the iron slag particles are spread uniformly inside the metallic matrix. There is also a reduction in the size of primary silicon, as well as morphological changes (acicular to globular shape). The wear behavior was calculated using a pin-on-disk wear set up in accordance with ASTM G99 standard. The composites were employed to dry sliding wear test under various operating conditions such as applied pressure (0.2–1.4 MPa), and sliding distance (0–3000 m). The 15F composite outperformed all other composite samples in terms of wear rate under all working conditions. When compared to the base alloy, it demonstrated a remarkable 67% drop in steady state wear rate. The enhancements in wear performance for the 15F composite were attributed to the effects of Fe slag reinforcement. The inclusion of iron slag particles induced strong interfacial bonding between matrix and reinforcement particles improving the durability of the mechanical mixed layer developed during relative motion. Importantly, the wear rate parameters of the 15F composite were similar to those of the brake drum material used in commercial applications. This emphasizes the composite suitability for usage in a variety of automobile components. [ABSTRACT FROM AUTHOR]

SiMo ductile irons, typical heat-resistant materials, are subjected to varied wear environments during operation in high-temperature applications. SiMo ductile iron castings of different thicknesses were cast in investment and greensand molds, achieving a wide range of cooling rates. The present work aims to investigate the effect of the cooling rate and alloying elements (Cr, V, and Ni) on the microstructure and the abrasive wear behavior of these grades of SiMo ductile iron at high-temperature 700 °C under different loads. Thermodynamic calculations were used to propose the phase diagrams, critical transformation temperatures, and phase volume fractions in all SiMo alloys by using the Thermo-Calc software then verified by and Differential Scanning Calorimetry (DSC). The microstructure of unalloyed SiMo ductile cast iron consists of graphite nodules and carbides embedded in the precipitates at the grain boundary regions in a ferrite matrix. The alloyed SiMo microstructure contains nodular graphite and the carbides promoted by the alloying elements (Cr and V). The alloyed SiMo alloys exhibit higher wear resistance than unalloyed ones. These wear results support that the microstructure plays a chief role in wear loss. The combination of M6C, VC, and M7C3 carbides embedded in a ferrite-pearlite matrix (alloyed SiMo) seems to be more resistant to wear than the ferritic matrix with lamellar pearlite and eutectic M6C carbides (unalloyed SiMo). [ABSTRACT FROM AUTHOR]

Aluminum matrix composites reinforced with ceramic particles are widely used in parts and components operating under severe abrasive friction and wear conditions. This work investigates the effect of the particle size and the amount of B4C and SiC reinforcements ranging from 0 to 25 wt % in the initial powder mixture on the microstructure, micromechanical properties, and abrasive wear resistance of aluminum matrix composites. It is shown that B4C and SiC reinforcement particles contribute to the refinement of the aluminum matrix. Micromechanical properties determined by instrumented microindentation indicate that the hardness of the composites exceeds the hardness of sintered aluminum, and Al–25% SiC composite has the highest mechanical load resistance compared to other composites studied. Pin-on-plate wear tests of samples sliding against fixed electrocorundum grains revealed the greatest abrasive wear resistance of Al–25% SiC and Al–12.5% В4С–12.5% SiC composites. The minimum resistance was observed for Al–25% B4C. These materials demonstrate adhesive and abrasive wear behavior with the formation of characteristic wear grooves and tear pits. [ABSTRACT FROM AUTHOR]

Bandsaw blades are typical band-shaped cutting tools that are characterized by their low stiffness and micro-level cutting depth, resulting in distinct wear mechanisms compared to rigid cutting tools. In this study, the wear curve and wear mechanisms of the bandsaw tooth during the bandsawing of Cr12MoV cold-working steel were investigated. The tool life was divided into two stages: a rapid wear stage (Stage I) and a homogeneous wear stage (Stage II). In Stage I, the wear was dominated by chipping, although multiple wear mechanisms were found due to their relatively low manufacturing accuracy compared to rigid cutting tools, which resulted in remarkable differences in the cutting depth of each tooth. In Stage II, abrasive and adhesive wear were the primary wear mechanisms instead of chipping, which was related to the microstructure of Cr12MoV. Furthermore, methods for increasing bandsaw performance were proposed, based on the tooth wear mechanisms. [ABSTRACT FROM AUTHOR]

This study investigated the effect of abrasive water jet (AWJ) kinematic parameters, such as jet traverse speed and water pressure, abrasive mass flow rate, and standoff distance on the surface of BK7. Nozzle A reinforced with a 100 nm particle-sized coating of titanium alloy has more wear resistance compared to Nozzle B coated with nothing. Through analysis of variance and measurement of BK7 surface quality, it is concluded that the grooving and plowing caused by abrasive particles and irregularities in the abrasive water jet machined surface with respect to traverse speed (3, 7.2, 7.8, and 9 mm/min), abrasive flow rate (7 L/min and 10 L/min, 80 mesh) and water pressure (2 and 3 MPa) were investigated using surface topography measurements. The surface roughness (15.734 nm) of BK7 results show that a nozzle coated with titanium alloy has more hardness, which protects BK7 undamaged and super-smooth. The values of selected surface roughness profile parameters—average roughness (Ra) and maximum height of PV (maximum depth of peak and valleys)—reveal a comparatively smooth BK7 surface in composites reinforced with 2% titanium alloy in the nozzle weight at a traverse speed of 7.8 mm/min. Moreover, abrasive water jet machining at high water pressure (3 MPa) produced better surface quality due to material removal and effective cleaning of lens fragmentation and abrasive particles from the polishing zone compared to a lower water pressure (2 MPa), low traverse speed (5 mm/min), and low abrasive mass flow rate (200 g/min). [ABSTRACT FROM AUTHOR]

Developing a technology that increases the service life of valve seats in CNG/LNG-powered vehicles requires the appropriate selection of material and its application technology. Commercially used valve seat materials show accelerated wear under operating conditions, especially in natural gas vehicle engines. The authors developed a new material and technological concept to protect the valve seat in CNG/LNG-powered vehicles. Two materials were used in the research: Stellite 6 alloy and Fe 3 Al intermetal. A commonly used material for valve seats of combustion engines is Stellite 6. The Fe 3 Al is the new proposed material coating for the protection of the valve seats of internal combustion engines. The article compares the abrasive wear resistance of these materials. The abrasion tests were performed on a T-11 pin-on-disc tester, and the counter-sample was steel S235JR. The test conditions were similar to those prevailing during the operation of the valves in the head of the internal combustion engine, without the influence of temperature. The results indicate that the Fe3Al intermetallic compound is characterised by a lower coefficient of friction and wear intensity than Stellite 6. The results of exploitation tests confirm that the Fe 3 Al phase is a prospective material to be used as a protective material on the valve seat of vehicles. The authors made a mathematical model for the wear of the newly created surface layers and proposed hypotheses regarding the wear mechanisms of these layers. [ABSTRACT FROM AUTHOR]

Polymeric materials are widely used in aerospace, biomedical, marine, and agricultural applications due to their viscoelasticity and corrosion resistance. Polymeric materials fail due to wear during their service life, so studying their wear behavior is essential to control and predict their service life. This paper summarizes the progress of water lubrication research as well as experimental studies on the wear of polymeric materials under aqueous conditions. The effects of lubrication conditions, material formulation ratios, load, sliding speed, impact angle, abrasive particles, and temperature factors on the wear behavior of commonly used polymeric materials ideal for water lubrication (NBR, SBR, NR, EP, polyethylene, and their composites, etc.) are summarized in terms of the three most frequently occurring forms of wear, namely, two-body wet sliding wear, two-body erosive wear, and three-body wet abrasive particle wear. The results show that the mechanical properties, such as hardness, can be effectively changed by altering the formulation ratios of the materials, and the hardness and hydrophilicity of the formulations can further affect the wear and lubrication. In general, the coefficient of friction and the wear rate decrease with the increase in hardness, and the increase in temperature leads to the localized lubrication failure and the aging of the materials, which in turn leads to the intensification of wear. Among the working condition factors, load and sliding speeds are the most important factors affecting the wear, and the wear rate increases with the increase in the load and sliding speed; in contrast, the three-body wet abrasive wear is more obviously affected by the load. In the study of the impact angle effect, the overall trend of the erosion wear rate with the increase in the angle shows the first rise and then fall, the maximum value is mostly concentrated in the 45–60° between. Usually, the increase in the abrasive particle size can make the wear rate increase. Overall, the three-body wet abrasive wear of the rubber material wear rate shows first an increase and then a decrease. The research in this paper provides theoretical support and reference ideas for the tribological study of polymer materials in the water environment and puts forward the outlook for future water lubrication and material improvement of the research directions and applications. [ABSTRACT FROM AUTHOR]

In materials science, steel boration is a promising type of thermochemical diffusion process, the purpose of which is the introduction of hard and wear-resistant boride particles into the surface layers of the metal. The main disadvantage of boration is the fragility of borated layers, especially boride. Currently, there are promising methods for the formation of a composite structure, which are based on the treatment of surface layers of steels with concentrated energy flows (laser, electron beam and plasma). The work includes studies of microstructure, hardness measurements, analysis of phase composition, and determination of chemical composition in local locations, wear tests under various conditions, and adhesion testing of the coatings obtained after plasma boration. As the degree of alloying of the molten layer decreases in the direction from the surface to the base metal, zones of overeutectic, eutectic and pre-eutectic types with a different combination of structural components are formed. The material obtained after borating a mixture of 40% B + 10% Fe is characterized by the highest level of microhardness, which is 1000...1300 HV. The highest results in friction tests are provided by boration of a powder mixture of 40% B + 10% Fe.

Lightweight materials with better resistance to sliding wear are prominent candidates for automobile brake drums, clutch pads and cylinder block applications to facilitate fuel economy. This attempt is reserved to cater to materials with higher tribological quality needs. Less dense foamy pumice stone particles were involved in three different percentages (5, 10, and 15 wt%) to reinforce lightweight AZ31 Mg alloy. A stir-assisted squeeze casting technique was pursued to process the composite and refine the grain structure. A phase detection, elemental mapping and microstructure study were done through X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and scanning electron microscopy (SEM), respectively. An experimental dry sliding wear scrutiny was administered using a pin-on-disc apparatus by considering: (i) ambient and elevated temperature environments and (ii) three different levels of loads. The results reveal a significant drop in wear loss and a frictional coefficient for 15% pumice-loaded composite than the base alloy. Post-wear examination acknowledges the fact that the ambient temperature wear is governed by adhesive-abrasive wear and high temperature is by abrasive wear mechanisms. Worn-out scrutiny authenticates the presence of oxide layers and their role in lubrication. A comparative study with previous works upholds the novel magnesium composite is the right candidate for the mentioned automobile applications.

Ultralow-wear polyethylene (ULWPE) was proposed to replace conventional UHMWPE as an artificial joint material. Different molecular weights of ULWPE, ULWPE-200, ULWPE-300, and ULWPE-700 were examined against CrCoMo compared to conventional UHMWPE in multidirectional motion. The wear mechanism was elucidated from the perspective of macroscopic wear behavior and microscopic wear debris characterization. It was found that the morphologies of the ULWPE worn surface were similar to that of UHMWPE, with scratches, burnishing, and protuberances. ULWPE-700 possessed the lowest wear loss at all loading conditions, and the wear loss was 40.3% lower than that of UHMWPE at 3 MPa. Furthermore, wear debris was consistent in morphology and size range but showed differences in quantity, size distribution, and shape distribution. Combined with the wear surface morphology and wear debris analysis, it showed that plastic deformation was the main cause of wear debris formation and the wear mechanisms were adhesive wear and abrasive wear. Moreover, the FBA of ULWPE-700 was 64% lower than that of UHMWPE at 3 MPa, suggesting that ULWPE-700 wear debris had the lowest potential osteolysis. This study provides deeper insight into the bio-tribological behavior and the potential biological activity of ULWPE as an artificial joint material. [ABSTRACT FROM AUTHOR]

Improvement in mechanical properties of fibre-reinforced polymer composites through proper matrix modification has emerged as the significant trend in recent advanced technology. Dispersion of nanofillers in the matrix results in ultra-light weight, high strength, impact resistant and durable structures. In the current investigation, effect of the addition of varying percentages (0, 1, 3, 5 and 7 wt.%) of low-cost nanoclay to the unsymmetrical carbon/glass (C2G8) hybrid composites on mechanical, tribological and low-velocity impact (LVI) behaviour were investigated. Using traditional hand lay-up techniques, nanocomposite specimens were prepared. The results revealed that C2G8 hybrid composite with 5 wt.% loading of nanoclay possessed maximum hardness (35 HV), flexural strength (494 MPa), impact strength (Izod (119.022 kJ m−2), Charpy (563.922 kJ m−2)) and minimum specific wear rate (19.6 × 10−3 mm3 Nm−1) in comparison with other hybrid combinations. LVI test also revealed enhanced energy absorption (112.46 J) for hybrid nanocomposite against plain C2G8 hybrid composite. Furthermore, the damage depth and areas were observed by visual inspection and scanning electron microscope to account for best possible structure–property relationship. Developed hybrid nanocomposite may be considered as a suitable material for various automotive applications. [ABSTRACT FROM AUTHOR]

Friction coefficient depends on various factors or surface characteristics during tribological testing, and this friction coefficient can be modified by altering the properties of one of the two contacting surfaces. It is crucial to monitor the friction coefficient continuously, not only at the conclusion of the test. This research examined the evolution of friction coefficient of silicon nitride (Si3N4) coating and H13 steel over different sliding distances (250, 500, 750, 1000 m). The study assessed surface wear and oxidation through three-dimensional profilometry and SEM/EDX. The findings indicated a reduction in friction coefficient by 22%, a decrease in wear rate by 88%, and a reduction in wear volume by 87% when comparing the silicon nitride coated steel to the uncoated steel. Furthermore, the changes in friction coefficient provided insights into the timing of the complete fracture of the hard coating. [ABSTRACT FROM AUTHOR]

The article presents the test results on the technology of surface hardening of castings from unalloyed and low-alloy nodular cast iron using the method of surface heat treatment, i.e., induction surface hardening and methods of thermochemical treatment, i.e. gas nitriding, nitrocarburizing, and nitrocarburizing with oxidation. The scope of research included macro- and microhardness measurements using Rockwell and Vickers methods, respectively, as well as metallographic microscopic examinations using a light microscope. Furthermore, abrasive wear resistance tests were performed using the pin-on-disk method in the friction pair of nodular cast iron – SiC abrasive paper and the reciprocating method in the friction pair of nodular cast iron – unalloyed steel. Analysis of the test results shows that the size and depth of surface layer hardening strongly depend on the chemical composition of the nodular cast iron, determining its hardenability and its ability to create diffusion layers. Medium induction surface hardening made it possible to strengthen the surface layer of the tested nodular cast irons to the level of 700 HV0.5 with a hardening depth of up to approximately 4000μm, while various variants of thermochemical treatment provided surface hardness of up to 750 HV0.5 with a hardening depth of up to approximately 200μm. Furthermore, induction surface hardening increased the resistance to abrasive wear of nodular cast iron castings, depending on the test method, by an average of 70 and 45%, while thermochemical treatment on average by 15 and 60%.

To improve the roughness prediction accuracy of Al2O3-based ceramic insulation coating on bearing surfaces, a method based on the spectral confocal principle was proposed for measuring the surface of grinding wheels and quantifying the characteristic parameters of abrasive particles. The abrasive characteristic parameter K of the grinding wheel surface, the grinding wheel line speed vs, the workpiece feed speed f, the cutting depth ap, and the normal grinding force F were taken as input parameters. A BP neural network prediction model of workpiece surface roughness, which directly reflects the time-varying state of the grinding wheel surface, was established. The prediction performance of the network model was verified using known grinding samples and four groups of unknown samples after grinding wheel wear. The results show that the predicted roughness results of the BP network model with known samples are consistent with the actual roughness results in terms of regularity and numerical values, with network output errors are all less than ± 0.04 μm. The network prediction accuracy for the four unknown samples decreases, but the absolute value of the maximum relative error does not exceed 20.00%. The neural network prediction model, which includes the characteristic parameters of abrasive particles on the grinding wheel surface , can be used to predict the roughness of Al2O3-based ceramic insulation coating on the bearing surface under the time-varying state of abrasive wear on the grinding wheel. It also demonstrates a certain generalization ability for unknown samples.

The current trend is the ecological consciousness of replacing synthetic fibers with natural fiber. However, several restrictions exist on using natural fibers/fillers, including compatibility, hydrophobicity, and locality. The natural material chosen for the present investigation, Acacia nilotica, is short and cylindrical; the same has been used as reinforcement after being chemically treated with silane and grinded into fillers in the present study. Grinded silane-treated A. nilotica fillers were added in a range of 0, 2, 4, and 6 weight percent to the epoxy matrix. Conventional hand layup was used to manufacture composite materials using epoxy resin and hardener. The manufactured composite's tribological properties were evaluated according to ASTM G99-17 using the pin-on-disk machine under two-body abrasive wear conditions. L-16 orthogonal arrays were used to conduct the research. Load, sliding distance, and material were the process input parameters, and the results were evaluated using the Specific Wear Rate (SWR) and Coefficient of Friction (COF). Analysis of variance (ANOVA) was used to analyze the significant variables. EDAS was used to optimize the output. The abraded surfaces were finally studied using worn surface morphology. According to the findings, silane-treated A. nilotica filler is a new and promising resource as a sustainable raw material for reinforcement in polymer composites manufacturing lightweight materials. Results revealed that the optimized values were 6 wt%, load at 20 N, and sliding distance of 225 m. SWR values decreased by 61.2%, and COF values decreased by 34.3% in the case of 6 wt% composites compared to the unreinforced fiber composites. The rank of the sample was assigned according to performance by the EDAS process. [ABSTRACT FROM AUTHOR]

Agglomerated Diamond (AD) abrasives were prepared using a ceramic bond and microfine single-crystal diamond (SCD). Lapping experiments were conducted to investigate the lapping performance and wear mechanisms of AD abrasives. The processing mechanisms of AD abrasives on sapphire wafers were revealed through friction and wear experiments and Power Spectral Density (PSD) methods. The results show that compared to W3 SCD, the material removal rate (MRR) of AD abrasives increased by 89.1 %, while the surface quality of the processed sapphire wafers was similar. Under the polyurethane lapping discs, AD abrasives achieved an MRR of 3.62 μm/min and a surface roughness (Ra) of 15.3 nm. The sapphire surface lapped with AD abrasives was the smoothest, with the PSD curve of the surface profile showing less noticeable layering, and the PSD values of the surface profile in the same frequency domain space were relatively the lowest. During the lapping process, the wear mechanisms of AD abrasives were identified as abrasive wear and micro-fracture. Under the impact and compression between the workpiece and the lapping discs, the fine SCD particles on the surface of the abrasives would wear and detach, and the network structure of the ceramic bond would fracture, exposing the fine SCD particles embedded in the bond to the surface, thus renewing and self-sharpening the cutting edges. • Agglomerated Diamond (AD) abrasives with multi-edge cutting and micro-fracture characteristics were prepared and used for loose-abrasive lapping of sapphire wafers. • The lapping properties and wear mode of AD abrasives were investigated. • The processing mechanism of AD abrasive is revealed through friction wear test and Power Spectral Density (PSD) analysis method. [ABSTRACT FROM AUTHOR]

Chemical strengthening of glass represents a standard technology for fabricating damage‐resistant protective covers. Still, little attention has been paid to modifications in the tribological properties of ion‐exchanged glass surfaces. This work reports on scratch testing of a chemically strengthened alkali‐borosilicate thin glass. Diffusive Na+/K+‐ion exchange produces a residual surface compressive layer with compressive stress of 200–340 MPa and layers depths between 16 and 50 µm, depending on exchange temperature and treatment time. This leads to notable changes in the surface mechanical properties, such as an increase in surface Young's modulus, indentation, and scratch hardness. Surprisingly, the Na+/K+‐ion exchange is shifting the onsets of scratch‐induced microcracking and microcracking to lower normal loads. The accelerated buildup of lateral indentation stress in glasses with high scratch hardness was found to be responsible for the lower threshold loads of microcracking and abrasive wear in chemically strengthened alkali‐borosilicate thin glass. [ABSTRACT FROM AUTHOR]

With the escalating industry-wide requirement and based on the inherent properties, recently the polymeric composite is in more demand for tribo-application. Again, the development of eco-friendly material by inclusion of materials derived from natural resources is also becoming one of the promising areas of the interest. In this current study, an agricultural residue like pistachio shell particulates (PSP) is used as bio-filler to develop polymer matrix composites for tribo-application. The polyester matrix test specimens are fabricated with variation of PSP filler concentration ranging from 0 to 7 wt% by the hand lay-up method. The influence of filler content on both mechanical and sliding wear performances of the composites is studied. As per ASTM standard, several tests like tensile, flexural, impact and micro-hardness test have been carried out. To observe abrasive wear response of the developed composite, the dry sliding wear test has been conducted on a pin-on-disc wear tester in accordance with ASTM standard under five different normal loads, sliding distances and three distinct sliding velocities. The findings revealed that the mechanical performances of the composites are enhanced with the increase in the PSP filler concentration. Optimum properties such as hardness of 13 HV, tensile strength of 36.55 MPa, flexural strength of 43.66 MPa and impact strength of 16.36 kJ/m2 are obtained at 5 wt% reinforcement of PSP filler. Again, an improvement in sliding wear resistance by 39.57% is also noticed. During the examination of worn surface by scanning electron microscope (SEM), the appearance of cracks and the creation of grooves at the lower filler loading and formation of wear debris are noticed at the higher filler loading. [ABSTRACT FROM AUTHOR]

This article presents the results of abrasion wear resistance tests of wear-resistant steel and surfacing under laboratory conditions and natural operation. Abrasion wear resistance determined on the basis of the study by determining geometrical characteristics of the alloying additives using computer image analysis methods, as well as examining the changes occurring on the surface of the workpieces and their wear intensity. Based on the results obtained from laboratory tests, it was noted that AR steel exhibited 14 times greater wear than the padding weld. This wear is affected by alloy additives, which, for the padding weld, are chromium additives. The microstructure image shows that soil mass had a destructive effect mainly on the matrix of the material, whereas in the areas with high concentrations of chromium precipitates, this effect was significantly weaker. The operational test results showed that within the area of the tine subjected to hardfacing, the material loss was lower than that for the same area of the tine in the as-delivered state. For the hardfaced tine, a 7% loss of volume was noted in relation to the operating part before testing and following the friction process. However, for the operating part in the as-delivered state, this difference amounted to 12%. [ABSTRACT FROM AUTHOR]

The wheel set of a rail vehicle with a disc brake is the basic assembly of a rail vehicle exposed to abrasive wear. From the operational point of view, the wear process of the wheels and brake discs is uneven, which for the carrier involves switching off the vehicle, once when the maximum wear of the discs is reached and again when the wheels wear out. The process of both untying the wheel set from the bogie, dismantling the wheels and discs from the axle is a time-consuming and expensive process, which consequently affects the exclusion of the vehicle from planned traffic. In the article on the basis of brake disc wear results, 3 concepts of bogie management were proposed. The first concerns the bogie rotation, the second and third concepts concern the exchange of bogies with and without rotation. Using the MUZ multi-criteria programming method, the concepts were evaluated and the best one was selected taking into account the evaluation criteria. The aim of the article is to present concepts that reduce the wear of discs brake systems in a multi-unit traction unit using bogie migration under the vehicle. [ABSTRACT FROM AUTHOR]

The results of the study of patterns of destruction and their influence on the wear resistance of low-alloy steel 65G in the unstrengthened state, as well as after strengthening by thermal and electroerosion treatment during movement in soils of different fractional composition, are presented. It has been confirmed that under such conditions the phenomenon of the presence of a critical size of abrasive particles (CPS) is realized on the wear surface. The role of the geometric size of the particles in the formation of the wear resistance of steel consists in the regulation of active deformation and fatigue phenomena on the wear surface by changing the level of force acting on it. The influence of the fractional composition of the soil on wear resistance is carried out through the rheological fatigue parameter in the following dependence: the greater the rheological-fatigue parameter, the higher the wear resistance of steel. Therefore, the mechanical component of the contact interaction is decisive in the strength basis of the wear mechanism. Therefore, when choosing a brand of low-alloy steel for the manufacture of machine parts intended for operation in soils of different fractional composition, it is necessary to be guided by its ranking according to the rheological-fatigue parameter. The role of the fractional composition of the soil in the formation of the rheological- fatigue parameter is carried out mainly through the cyclic viscosity of deformation in the sublayer of nonlinear effects in the vicinity of the crack tips of the surface layer in the following dependence: the higher the cyclic viscosity, the lower the rheological-fatigue parameter of steel. The stress that is cyclically repeated during abrasive wear causes in the sublayer of nonlinear effects in the vicinity of the crack tips of the surface layer two opposite phenomena that occur simultaneously: strengthening and weakening. At the same time, the action of the weakening process in soils of different fractional composition is more effective than strengthening. In the region of the subcritical geometric dimensions of the abrasive particles, the intensity of hardening is significantly reduced due to the increase in the effectiveness of the hardening action due to the additional contribution of dispersion hardening. However, this does not entail qualitative changes in the wear process. [ABSTRACT FROM AUTHOR]

As a contribution of recycling of polymers in the automotive industry, recycled polyvinyl butyral (rPVB) from automotive windshields is being explored as a solid lubricant reinforcement for improving lubricity of engineering polymers. This work aims to evaluate the tribological behavior (coefficient of friction [CoF] and wear resistance) of polyamide 6 (PA6) and glass-fiber-reinforced polyamide 6 (PAGF) blended with rPVB as solid lubricant under two-body and three-body abrasive conditions. The different polymer blends were produced by adding recycled polyvinyl butyral (rPVB) into a matrix of either a commercial polyamide 6 (PA6) or a commercial 30% glass-fiber reinforced polyamide 6 (PAGF). The tribological tests were conducted in an instrumented microabrasion tester for generating wear and measuring the coefficient of friction (CoF) in both dry and microabrasion conditions. In the dry condition, rPVB was effective in reducing the CoF for both PA6 and PAGF. Two-body abrasion was found as the predominant wear pattern in the dry condition. On the other hand, in the microabrasion condition, the additions of rPVB were not totally effective since they produced a wear resistance increase for PAGF but a reduction for PA6, which was ascribed to a notable decrease in toughness for PA6 when adding rPVB. Well-defined plowing traces and several SiC particles embedded in the scars were the predominant patterns in all the materials. In both PA6 and PAGF, CoF increased with the rPVB additions. [ABSTRACT FROM AUTHOR]

Microstructural heterogeneities of an ASTM A128 grade C steel subjected to heat treatments and their effect on abrasive wear behavior were investigated. The heat-treatment process involved different austenization times at 1050 °C and quenching media. To characterize the effects of heat treatment on the material's microstructure and mechanical behavior, two microscopy techniques were used: optical microscopy (OM), and scanning electron microscopy (SEM). The chemical composition of the material was obtained using X-ray fluorescence (XRF) optical emission spectrometry. The variation in carbide composition was evaluated using X-ray Energy Dispersive Spectroscopy (EDS). To characterize the mechanical behavior of the steel, hardness measurements and abrasive wear tests were performed after homogenization annealing and quenching treatments. The results showed that the heat-treated samples developed a heterogeneous microstructure, with the presence of austenitic grains and Martensite around the surface of the samples induced by decarburization in both the protected and unprotected specimens. The specimens with lower decarburization presented less formation of Martensite and precipitated carbides, resulting in lower hardness values and higher abrasion resistance (solution treatment at 1080 °C for 1 h + sand protection + brine quenching). [ABSTRACT FROM AUTHOR]

This article presents the effect of the conditions of abrasive compounds on the wear of samples made by different methods. The 28MnB5 steel was used, which is intended for agricultural components, to which two arc and laser coatings were applied. The study included the analysis of microstructure, microhardness, roughness, and tribological experiments on a dedicated stand. The arc coating was found to significantly improve the tribological properties compared to the samples without the coating. Varied wear results were obtained for the laser coating depending on the parameters of the abrasive compound. Studies of the surface roughness of the samples showed that the concentration and pH of the abrasives have a significant effect on the changes in the surface parameters after the tribological tests. The results of the tribological experiments indicated that wear resistance for some of the abrasive mass conditions was improved by the application of heat-applied coatings. In addition, it was found that the power consumption on the stand was the highest for abrasive mass conditions of a 10% moisture content and a pH of 10. For these test conditions, the mass loss was four times higher than for the parameter with W0% and pH7. The energy consumption of the stand was 60 kWh lower for this variant than for the parameter with W10% and pH10. The results of the study have important practical applications that can help in the selection of materials for agricultural machinery components, depending on the abrasive mass conditions. [ABSTRACT FROM AUTHOR]

Seal wear caused by hard particles intruding into the seal surface is one of the main causes of seal failure. In this manuscript, the tribological properties of hydrogenated nitrile rubber (HNBR) in the intrusion of five different sizes of garnet particles into the friction pair were studied through the pin-disk rubbing pair. The experimental results show that the particles change the contact pattern of the friction pairs, thus changing the amount of rubber wear. Different forms of particle motion contribute differently to the friction coefficient, and the particle sliding on the rubber surface contributes the most. As the particle size decreases, the friction coefficient tends to increase and then decrease, which can be explained by energy dissipation theory. [ABSTRACT FROM AUTHOR]

Surface roughness is a key factor when it comes to friction and wear, as well as to other physical properties. These phenomena are controlled by mechanisms acting at small scales, in which the topography of apparently flat surfaces is revealed. Roughness in natural surfaces has been reported to conform to self-affine statistics in a wide variety of settings (ranging from earthquake physics to micro-electro-mechanical devices), meaning that the height profile can be described using a spectrum where the amplitude is proportional to its wavelength raised to a constant power, which is related to a statistical parameter named Hurst exponent. We analyze the roughness evolution in atomistic surfaces during molecular dynamics simulations of wear. Both pairs of initially flat and initially rough surfaces in contact are worn by a third body formed by particles trapped between them during relative sliding. During the first sliding stages, the particles trapped between the first bodies scratch the surfaces. Once the former becomes coated with atoms from the latter, the wear process slows down and becomes "adhesive like." The initial particle sizes are consistent with the minimum size to be expected for the debris, but tend to grow by material removal from the surfaces and to agglomerate. We show that, for the particular configurations under consideration, the surface roughness seems to converge to a steady state characterized by Hurst exponent close to 0.8, independently of the initial conditions. [ABSTRACT FROM AUTHOR]

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The wear resistance of quenched-and-partitioned steel (Q&P) compared to martensite steel (Q&T) remains unclear. In this research, the wear resistance of Q&P steel and Q&T steel was researched by the means of the abrasive wear (AW) and impact abrasive wear (IAW) tests. The results show that abrasive ploughing was the main reason causing the material loss of Q&P and Q&T steel, while Q&T steel was subjected to severe fatigue spalling in the impact abrasive wear tests. Under the abrasive wear test, Q&T steel has better wear resistance due to its higher initial hardness. Under the impact abrasive wear test, Q&P steel has better wear resistance. This is because the formation of the deformed layer, which consists of finer grains and newly formed martensite in the worn subsurface, increased the hardness of the Q&P steel, causing the hardness of the worn subsurface in Q&P steel to be higher than that of Q&T steel. Furthermore, Q&P steel has better resistance to cracks nucleation and propagation compared to Q&T steel. As a result, less material loss was caused by fatigue spalling in Q&P steel under the impact abrasive wear tests. [ABSTRACT FROM AUTHOR]

The idea for this work came from a market need to obtain coatings or sealants that would extend the useful life of metallic materials in applications that involve exposure to corrosive environments. The main objective of the nanoceramic sealant studied in this work is to extend the life of metallic fasteners. To evaluate the performance of the sealant from other perspectives, microstructural analysis, adhesion test, micro-scale abrasive wear tests and corrosion test were carried out. These tests were performed on samples coated only with white zinc, which is commonly used in the fastener industry, and on samples coated with white zinc followed by application of the nanoceramic sealant. The application of the nanoceramic sealant contributed to the improvement of corrosion resistance and reduction of the corrosion rate. The corrosion rate of the sample coated with the sealant reduced by 62.2% when compared to the sample that only went through the white zinc coating process. The coating showed low adhesion to the substrate with the presence of severe delamination and microcracks. This feature contributed to the low wear resistance presented by the coating under the conditions studied in this work. Less attention, compared to studies involving corrosion resistance, has been given to wear resistance in the fastener industry. The results obtained in this paper show that the study of tribological behavior is an important factor in increasing the efficiency of fasteners applied in harsh environments.

The primary objective of the current study is to enhance the damping capability of polylactide (PLA)/jute fiber composites without sacrificing their strength and stiffness. With this objective, multiphase composites were fabricated with silane-treated jute fiber and nitrile butadiene nano rubber modified polylactide. The mechanical and damping behaviors of the developed multiphase composites were evaluated. The modulus and strength of the composite were effectively increased by the silane-treated jute fiber. However, the impact strength and damping capability also decreased with chemical treatment of the jute fiber. Conversely, PLA was successfully toughened by the addition of rubber nanopowders, leading to significant improvements in the impact strength and damping ability of the composites. This improvement was achieved with minimal compromise in terms of stiffness, strength, and environmental appeal. In addition, modification of the PLA matrix with rubber nanopowders also resulted in the enhancement of abrasive wear resistance.

This paper presents the results of research conducted in the field of the technology of surface hardening of castings from unalloyed and low-alloy nodular cast iron using the laser remelting method. The range of studies included macro- and microhardness measurements using Rockwell and Vickers methods as well as metallographic microscopic examinations using a scanning electron microscope. Moreover, abrasive wear resistance tests were performed using the pin-on-disk method in the friction pair of nodular cast iron—SiC abrasive paper and the reciprocating method in the friction pair of nodular cast iron—unalloyed steel. Analysis of the test results shows that the casting surface layer remelting by laser for unalloyed nodular cast iron results in a greater improvement in its resistance to abrasive wear in the metal–mineral system, as compared to low-alloy cast iron. Additionally, carrying out the laser hardening treatment of the surface layer made of the tested grades of nodular cast iron is justified only if the tribological system of the cooperating working parts and allowable dimensional changes during their operation are known. [ABSTRACT FROM AUTHOR]

Martensitic low-alloy steels are widely used in machine construction. Due to their declared weldability, arc welding is most often used to join elements made of this type of steel. However, the high temperature associated with welding causes unfavourable changes in the microstructure, resulting in reduced abrasion resistance. Therefore, it is important to know the tribological properties of the welded joint. This article presents the results of a study on the abrasion wear resistance of a welded joint of an abrasion-resistant steel. This study tested a welded joint of an abrasive-resistant steel produced by the arc welding method. Wear testing of the welded joint was carried out under laboratory conditions by the ball-cratering method in the presence of abrasive slurry on the cross-section of the welded joint. Based on the test results, the change in the abrasive wear rate of the material as a function of the distance from the welded joint axis was determined. It was also found that the thermal processes accompanying welding caused structural changes that increased the wear rate index value. Adverse changes in the tribological properties of a welded material persist up to a distance of approx. 20 mm from the weld centre. [ABSTRACT FROM AUTHOR]

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ni60-WC coatings with different WC contents on the bucket tooth substrates were pre- pared using laser cladding technology. Their abrasive wear properties were assessed using the dry sand rubber wheel test system. The substrate and the hard-facing layer were tested for comparison. The results showed that the hardness of the Ni60-WC coatings increased with the increase in WC content. The wear resistance of the bucket tooth substrate was greatly improved by hard-facing and laser cladding Ni60-WC coatings. The wear rate of the hard-facing layer was reduced to 1/6 of that of the tooth substrate. The wear rate of the laser cladding coatings with 20–40 wt.% WC was similar to that of the hard-facing layer. It is worth mentioning that the wear rate of the coatings with 60–80 wt.% WC was only 1/4 of that of the hard-facing layer. Micro-cutting with surface plastic deformation was the main wear mechanism of the substrate to form narrow and deep furrows. The wear mechanism of the hard-facing layer was mainly plastic deformation with a wide groove, and the surface cracks promoted the removal of the material. The removal of the binder phase caused by micro-cutting was the main wear mechanism of the laser cladding Ni60-WC coatings. However, the hard phase of WC hinders micro-cutting and plastic deformation, which improves the wear resistance of the coating. [ABSTRACT FROM AUTHOR]

The influence of the abrasive particle size and modifiers (low molecular weight liquid rubbers (LMWRs), sulfidosilane) on the rate of wear on abrasive paper of rubbers based on natural rubber (NR), carbon black (CB), and polyoxadiazole (POD) fiber is studied as a function of structure and mechanical properties of rubbers. Model rubber blends were prepared in a closed-type mixer, the abrasive wear tests were conducted on a drum-type machine, the structure and the mechanical properties of rubbers were characterized by DMA, static tensile tests, hardness measurements, and tear resistance. The wear surfaces were analyzed by SEM. Tests have shown that the addition of fiber does not affect the rate of abrasive wear of the original NR/CB rubber regardless of the grain size of the abrasive. Addition of modifiers that increase tensile modulus M10, hardness HSh, tear resistance TR, tensile strength A, and degree of crosslinking γ reduces the wear rate under friction on coarse abrasive, which is characteristic of abrasive wear with a predominance of micro-cutting. The greatest influence, judging by the value of the correlation coefficient, is exerted by the value of M10, dependent on the bond strength between the matrix and the fiber, which allows predicting the wear rate of rubbers based on the results of mechanical tests. When worn on a fine abrasive paper, the increase in M10, HSh, TR, and γ on the contrary, raises the wear rate of rubber, and the tensile toughness has practically no effect on it. This is attributed to the predominance of the fatigue wear mechanism, in which the wear rate increases with contact stresses, in proportion to the strength properties, with tear resistance exerting the greater effect on the wear rate. [ABSTRACT FROM AUTHOR]

Numerical simulations play a vital role in the modern engineering industry, especially when faced with interconnected challenges such as particle interactions and the structural integrity of conveyor systems. This article focuses on the handling of materials and emphasizes the importance of using parametric numerical analysis to improve efficiency, reduce wear, and enhance the structural integrity of horizontal screw conveyors. Through the utilization of the Design of Experiments, we systematically investigated critical parameters such as screw pitch, clearance, wear, rotational velocity, and additional structural factors. This examination was carried out within a well-defined parametric framework, utilizing a combination of software tools provided by the Ansys suite and Minitab. The findings demonstrate the effectiveness of the Design of Experiments analysis in achieving improved performance and provide valuable insights for engineers and researchers involved in the design of conveyor systems. Furthermore, this comprehensive approach clarifies how conveyor systems respond to changes in parameters and highlights the complex interaction between transported particles and the conveyor system. We present a detailed analysis that clarifies the complex relationships and dependencies among different parameters, providing engineers and researchers with valuable insights. By understanding the interactions of these factors, the methodology provides not only results but also a strategic framework for advancing conveyor system design and engineering practices. [ABSTRACT FROM AUTHOR]

Cutting edge preparation is a precision machining process that improves the surface quality of cutting tools through the relative movement of abrasives and the tool. Research on removing materials in drag finishing can be greatly beneficial to tool manufacturing. This paper proposes the hypothesis that both abrasive wear and erosion wear act on the surface of milling tools and discusses the material removal models for abrasive wear and erosion wear. The influence of immersion depth, abrasive velocity, abrasive radius, and abrasive density on the material removal rate in two material removal forms is compared and validated by discrete element simulations. The results show that immersion depth has a greater impact on abrasive wear, while abrasive properties have a greater impact on erosion wear. The correlation between simulation results and theoretical models demonstrates the sensitivity of the two forms of wear on this surface to parameter change differences. Dragging finishing was conducted to verify the effectiveness of the simulation, and the effects of immersion depth, dragging velocity, and abrasive properties on the edge radius and form factor (K value) were studied. [ABSTRACT FROM AUTHOR]

In the current work, twin-wire arc-sprayed copper coatings are investigated to reduce the spread of pathogenic germs in broiler farming. Compressed air and nitrogen are used as process gasses, while the coating torches are varied. The results demonstrate a reduction of 99% pathogenic load due to the presence of coatings in comparison with the uncoated nickel-chromium-steel. This accounts especially for the bacterial strains E.coli, S.aureus and E.cecorum, which are the predominant bacteria in broiler farming. Moreover, posttreatment processes like cold plasma, tungsten inert gas arc processing and shot peening are investigated to further increase the bactericidal properties and abrasion resistance characteristics of the coatings. Further investigations involve the microstructure and the electrical conductivity of the coatings. In this work, it is demonstrated that copper-coated surfaces have an inhibitory effect on bacterial growth of the three investigated bacterial strains compared to the uncoated bulk nickel-chromium-steel material. [ABSTRACT FROM AUTHOR]

The discrete element method (DEM) and response surface methodology (RSM) were used to determine the input parameters and combination of operational factors required for optimizing the Jerusalem artichoke (Helianthus tuberosus L.) harvesting tool in cohesive soil. The DEM soil model consisted of particles with different radii in three shapes calibrated using angle of repose and cone penetration data. Compared with data from a soil bin subsoiler evaluation, the DEM model showed acceptable relative errors for draught force (6.7%), vertical force (4.5%), and furrow width (9.3%). The effects of operational factors, including forward speed, vibration frequency, and amplitude, on response variables such as draught and vertical forces, drawbar power, and abrasive wear were analyzed for three harvesting shovels (S-shape, step-shape, and fork-shape). The ratio of vibratory speed to forward speed (velocity ratio, Vr) was used to analyze the combined effect of the factors. The operational factors significantly affected all the response variables (p<0.05). At Vr > 1 (1.2-3.9), soil reaction forces and drawbar power were considerably reduced. The optimal parameters for minimizing the response variables were 2.5 km h-1 forward speed, 14.5 Hz frequency, 30 mm amplitude, and S-shape shovel at Vr = 3.9. The minimum draught force, vertical force, drawbar power, and Archard wear depth were 4.64 kN, 0.41 kN, 2.64 kW, and 2.36 mm, respectively, at an operating depth of 350 mm. Operating in vibratory mode reduced draught force by 54% with the full width of the implement. Future work should include Jerusalem artichoke tubers in the simulation and experimental validation. [ABSTRACT FROM AUTHOR]

Two chromium-rich carbide hard-faced plates, alloy—A and alloy—B, were subjected to a 3-body dry sand abrasion test. The difference was in the coating microstructure. Alloy-A contains globular chromium carbide (M7C3 type) in the austenite matrix, whereas alloy—B is composed of a banded structure with an alternate layer of carbide and austenite. Alloy B showed a superior abrasion resistance (nearly 40%) than alloy—A. A detailed microstructural investigation was made on the abraded surface. The higher abrasive wear resistance of alloy-B was attributed to the coating morphology, the composite-like microstructure resulted in an effective strain distribution among the austenite matrix and carbides. This postulate was supplemented by higher average misorientation, which was observed at sub-surface regions of the worn-out specimen, leading to form a strain-induced martensite. However, in alloy—A, the abraded surface contained abundant broken carbides. [ABSTRACT FROM AUTHOR]

The surface features of additively manufactured polymer parts differ compared to extruded polymer parts and decide their performance in terms of power transmission applications. Layer thickness is one of the important process parameters chosen based on the part complexity and production speed, influencing the surface features. The abrasive wear performance of high-performance polyether ether ketone (PEEK), which determines the performance of power transmission elements such as bearings and gears, is reported in this article. The layer thickness employed in fabrication, which varies from 0.1 mm to 0.35 mm, influences the surface roughness, real contact area, and hardness of the as-printed PEEK. The friction coefficient and wear resistance of a printed part are influenced by the layer thickness employed, indicating the need for a proper choice of layer thickness for power transmission applications. Samples printed with a layer height of 0.25 mm and higher exhibited an increase of friction coefficient and wear loss due to the weak surface integrity. The friction and wear characteristics of additive manufactured samples are compared with extruded samples. Wear debris accommodation in the grooves of the as-printed surfaces accelerates the wear due to three-body abrasion in high layer thickness samples. The micromechanisms of wear damage in different layer thickness samples are discussed. The observations indicate the strong influence of layer thickness and facilitate the selection of appropriate layer thickness for the required friction coefficient in a particular application. [ABSTRACT FROM AUTHOR]