Abstract
In dredging engineering, the parts of dredging and conveying system which contact with dredging mixture often suffer from serious wear and short service life. In order to improve the ...durability of materials, new materials and generation processes are constantly proposed. It is always a difficult work to analyze the wear properties and mechanism of materials.In this paper, dry friction and abrasive wear tests were carried out on Cr15, Cr26, Fedur®40, medium manganese steel and XGG with Q235 carbon steel as the comparison material. The wear mechanism of materials was analyzed by scanning electron microscope (SEM) observation on the wear surface of materials. Under the test conditions, the dry friction wear rates of the five materials were 6.98×10
−6
mm
3
/Nm,5.71×10
−6
mm
3
/Nm,20.2×10
−6
mm
3
/Nm,21.9×10
−6
mm
3
/Nm and 5.39×10
−6
mm
3
/Nm respectively.The wear rates of abrasive wear tests were 58.3×10
−6
mm
3
/Nm,25.2×10
−6
mm
3
/Nm,83.4×10
−6
mm
3
/Nm,30.9×10
−6
mm
3
/Nm and 32.1×10
−6
mm
3
/Nm respectively. The results show that the metal surface is covered with coarse and deep cutting and chipping marks under abrasive wear, while the metal surface only has fine furrowing and a little fatigue spalling under dry friction wear. The wear rate of abrasive wear of five wear-resistant materials is much higher than that of dry friction wear. Cr26 and XGG showed better wear performance than other materials under the two test conditions.
In order to obtain higher wear resistance steel for the application in mining machines, new modified medium manganese austenitic steel (MMAS) was developed. The impact abrasive wear properties were ...investigated on MLD-10 impact wear test equipment. The wear resistant and strengthening mechanisms of MMAS were analysed by SEM, TEM and XRD observation. Our research results show that the wear mass loss of MMAS decreases about 30% in comparison to that of martensitic steel, which suggests that medium manganese austenitic steel has the higher impact abrasive wear resistance than the martensitic steel. It is found that 1mm thick hardened layer is formed on the MMAS abrasive surface. In this harden layer, the highest Vickers hardness is about 531HV, and the highest Rockwell hardness is about 52HRC at the layer of 50μm from the surface. It is proved that the harden layer substantially enhances wear resistance of MMAS. The wear resistance strengthening mechanism of MMAS is found to be dependent on the impact energy. For the lower impact energy, the strengthening mechanism is controlled by the composite reinforcement of martensitic transformation, dislocation and stacking fault. For the high impact energy, the strengthening mechanism is controlled by the martensitic transformation, deformation twin and dislocation. The field wear tests of MMAS were done on the scraper conveyor machines in coal mines, the test results indicated that the wear duration of MMAS transportation slots could be double of the martensitic wear resistant steel slots.
•Report new modified medium manganese steel with high impact wear resistance.•Thick harden subsurface layer by friction strengthening mechanism is found.•Wear resistance enhancing mechanism is dependent on the impact energy.•Field tests prove the doubled wear duration than that of martensitic steel.
Austempered ductile irons (ADIs) are used in applications commonly exposed to severe contact conditions, and as a consequence wear damage frequently followed by failure of components. Hence, wear ...resistance of the material governs the final life time of a component. In the present work, the sliding wear resistance of two ausferritic spheroidal graphite ductile irons ADI1 and ADI2 used commonly in mining and construction equipment was investigated. ADI1 and ADI2 were heat treated to a similar strength, the volume fraction of the carbon-rich austenite in ADI1 and ADI2 was around 30% and 16%, respectively, and they both contained 10 – 13% nodular graphite. The wear tests were performed using a slider-on-flat-surface (SOFS) tribometer. Case-hardened steel plates made of a high strength steel, 22NiCrMo12–F, were used as the counterface. The wear tests were conducted under lubricated sliding contact at normal loads of 50, 100, 200 and 300 N, and at each load level sliding at 100, 200 and 300 m. The friction force between contacting surfaces was continuously monitored during sliding. The lubrication used in the present investigation was a mineral-oil-based paste commonly used in applications where high frictional heating is generated. Wear mechanisms of the tested specimens were investigated by means of optical and scanning electron microscopy and X-ray diffraction, and the wear damage was quantified using a 3D-profile optical interferometer. The main wear mechanisms, severe plastic deformation and surface delamination, were discussed concerning test conditions and material properties. The ADI1 grade with the higher volume of carbon-rich austenite displayed better resistance to sliding wear at high normal loads. The higher normal loads promoted larger deformation at and beneath the contact surface and initiated austenite transformation into hard martensite. Thus, it was concluded that the increase of wear resistance in ADI1 was due to the formation of marteniste. On the other hand, the ADI2 grade with higher silicon content showed lower wear resistance at high normal loads. This was associated with cracking of the proeutectoid ferrite presented in ADI2.
•Wear mechanisms of ADI1 and ADI2 were investigated under reciprocal sliding contact. The influence of microstructure on wear performance of the tested materials was studied and evaluated.•Severe plastic deformation and surface delamination were the dominant wear mechanisms observed for both ADI1 and ADI2.•ADI1 showed significantly better wear resistance at higher wear loads.•Transformation of austenite to martensite improved the wear resistance of ADI1 grade.•High silicon content in ADI2 increased the hardness and enhanced the wear resistance of the material at low wear loads.•Proeutectoid ferrite with high silicon content was susceptible to cracking at high normal loads.
This study investigates the mechanism of wear damage of human tooth enamel by applying reciprocating impact-sliding wear tests. Two sliding loads (20 N, 49 N) were applied. In general, greater the ...load, greater the wear damage. The wear tracks could be divided into the impact part and the sliding part, and the wear characteristics of enamel were different between two parts. Impact wear in the impact part displayed plastic deformation, quasi-plastic deformation and brittle fracture. Sliding part with abrasive wear exhibited microscale cutting and plowing processes. The impact motion was the main cause for the loss of enamel in the early stage which led to higher wear rate and a larger enamel loss. The sliding movement was the main reason for the loss of enamel in the later stage of the experiment which led to a steady wear rate and moderate material loss.
•The vertical load plays a role in the cycle-dependent wear behavior of enamel under the impact-sliding motion.•Impact wear is the main mechanism for the impact part.•Abrasive wear was responsible for the sliding part.•The impact part displayed plastic deformation, quasi-plastic deformation and brittle fracture.•The sliding part exhibited microscale cutting and plowing processes.
The tribological properties of cold sprayed Ni-WC metal matrix composite (MMC) coatings were investigated under dry sliding conditions from room temperature (RT) up to 400°C, and during thermal ...cycling to explore their temperature adaptive friction and wear behavior. Characterization of worn surfaces was conducted using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and Raman spectroscopy to determine the chemical and microstructural evolution during friction testing. Data provided insights into tribo-oxide formation mechanisms controlling friction and wear. It was determined that the steady-state coefficient of friction (CoF) decreased from 0.41 at RT to 0.32 at 400°C, while the wear rate increased from 0.5×10−4mm3/N·m at RT to 3.7×10−4mm3/N·m at 400°C. The friction reduction is attributed primarily to the tribochemical formation of lubricious NiO on both the wear track and transfer film adhered to the counterface. The increase in wear is due to a combination of thermal softening of the coating and a change in the wear mechanism from adhesive to more abrasive. In addition, the coating exhibited low friction behavior during thermal cycling by restoring the lubricious NiO phase inside the wear track at high temperature intervals. Therefore, cold sprayed Ni-WC coatings are potential candidates for elevated temperature and thermally self-adaptive sliding wear applications.
•Ni-WC composite coatings were processed using cold spray.•The addition of WC improved wear resistance under dry sliding conditions.•The friction of the cold sprayed Ni-WC coating decreased, while the wear increased at 400°C.•Thermal cycling illustrated self-adaptive tribological behavior of the Ni-WC coating.
Increasingly heavy workloads require components of construction machinery to have higher wear resistance, while the application of high-grade low-alloy wear-resistant steel in the machinery ...manufacturing industry is restricted greatly by its high hardness. Thus, it is of great significance to improve the wear resistance of low-alloy abrasion-resistant steels without increasing their hardness. A series of TiC-reinforced low-alloy abrasion-resistant steels with different hardness was developed by a conventional smelting-casting method. The microstructure of the TiC-reinforced steels was martensite, and micro- and nano-sized TiC particles were distributed in the martensite matrix. The three-body abrasive wear behaviors of a series of TiC-reinforced steels and conventional steels under dry and wet sand conditions were studied using dry and wet sand/rubber wheel testing machines, respectively. Under dry sand conditions, the main wear mechanism of TiC-reinforced steels was plastic deformation and fatigue spalling, and the wear resistance of the TiC-reinforced steels was more than 1.5 times that of conventional steels with the same hardness. Under wet sand conditions, the wear mechanism of TiC-reinforced steels was slight micro-cutting and peeling, the relative wear resistance of the TiC-reinforced steels was more than 1.4 times that of conventional steels.
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•TiC-reinforced low-alloy abrasion-resistant steels were developed to improve wear resistance without increased hardness.•TiC-reinforced steels had more than 1.5 times the wear resistance of conventional steels under dry and wet sand conditions.•Under dry sand conditions, the wear mechanism changed from micro-cutting to plastic deformation and fatigue spalling.•Under wet sand conditions, the wear mechanism became slight micro-cutting and peeling owing to lubrication by water.
Shear blades are extensively used in the recycling of metal scrap. A comparative study was conducted on used medium carbon NiCrVMo and CrB containing steel scrap shear blades to better understand ...their wear mechanisms under service conditions. The microstructure and hardness of worn cutting edges and bulk material were characterised by optical microscopy, scanning electron microscopy and microanalysis, X-ray diffraction analysis and macro/micro hardness testing. Moreover, tensile and Charpy impact properties were obtained from the bulk material. Several wear mechanisms were identified in both blades which are categorised in two main groups, i.e. spalling and progressive wear. The progressive wear due to abrasive, adhesive and oxidation wear was observed in both blades. In NiCrVMo-steel blades, spalling and crack propagation from surface/subsurface white etching layers mainly caused the severe wear. However, spalling due to delamination wear and crack propagation from severely deformed subsurface layers was the dominant severe wear mechanism in CrB-steel blades.
•The wear mechanisms were progressive wear and spalling wear in studied blades.•Progressive wear occurred due to abrasive, adhesive and oxidation wear.•Spalling wear was caused by delamination, white etching layers and crack propagation.•Spalling wear was mainly responsible for the severe wear.•Inclusions did not contribute to wear during shearing process in studied blades.
Machining cemented carbide coating on workpiece surface can effectively improve wear resistance of friction pair and reduce frictional coefficient and frictional wear. Through the research and ...development status of cemented carbide coating, the design of cemented carbide coating, processing method, wear mechanism, and bonding technology between cemented carbide coating and micro-/nano-texture are comprehensively described. Hardness, toughness, thickness, grain size, microstructure composition, etc. are important parameters affecting the wear resistance of cemented carbide coatings. The processing technology of cemented carbide coating has its advantages according to the working conditions of the workpiece. Among them, laser melting and plasma melting have good prospects for development. According to the working conditions of the workpiece, the wear mechanism of the hard alloy coating is different. The wear forms mainly include abrasive wear, adhesive wear, contact fatigue wear, and oxidation corrosion wear. The combination of cemented carbide coating and micro-/nano-texture technology can further improve the wear resistance of cemented carbide coating, which has good development prospects. Finally, the research prospect of wear resistance of cemented carbide coatings is put forward.
Sliding wear experiments were performed on CL65 wheel steel to analyze the changes of the microstructure at the outermost layer of the wear surface and wear property at different wear stages. The ...study showed that during sliding wear, the wear mechanism of the wheel steel blocks’ wear surfaces mainly concludes adhesion wear, abrasive wear and fatigue wear. The microstructure at the wear surface underwent changed, in the process of sliding wear, which accordingly altered the surface damage form and the wear weight. Based on the variation of wear weight, three stages could be divided: rapid wear, slow wear and stable wear. During the stage of rapid wear, the wear surface was mainly featured by furrow wear, with large spall at the same time, and the microstructure at the outermost layer was severe plastic deformation pearlite; during the stage of slow wear, the wear surface was mainly marked by furrow and adhesion wear, and the microstructures at the outermost layer were sub-micrometer ferrite subgrains and fragmented short-bar shaped cementite; during the stage of stable wear, the wear surface was characterized by small lamellar spall, and the microstructures at the outermost layer were equiaxed ferrite nanocrystalline grains and undissolved nanometer-sized cementite particles. In the process of sliding wear, abrasion resistance reached the peak when the microstructure at the outermost layer of CL65 wheel steel was subgrains. Compared with the plastic deformation pearlite layer, the nanocrystalline layer possessed sound abrasion resistance. However, between the nanocrystalline layer and the subgrain layer, stress was relatively large, which tended to cause cracks at their interface and further increased wear weight.
•Under sliding wear, the surface microstructure and abrasiveness undergoes changes.•When the wear surface is plastically deformed pearlite, the wear loss is greatest.•When the microstructure are sub-micrometer ferrite subgrains, the abrasiveness is the best.•Cracks form at the interface of the nanocrystalline-subgrain layer, which increases wear loss.
•A vibration-based wear mechanism identification procedure is proposed.•Wear evolution is tracked using an indicator of vibration cyclostationarity (CS).•The correlation between surface features and ...vibration characteristics is investigated.•Methods validated using lubricated and dry gear wear tests.
Fatigue pitting and abrasive wear are the most common wear mechanisms in lubricated gears, and they have different effects on the gear transmission system. To develop effective methods for online gear wear monitoring, in this paper, a vibration-based wear mechanism identification procedure is proposed, and then the wear evolution is tracked using an indicator of vibration cyclostationarity (CS). More specifically, with consideration of the underlying physics of the gear meshing process, and the unique surface features induced by fatigue pitting and abrasive wear, the correlation between tribological features of the two wear phenomena and gearmesh-modulated second-order cyclostationary (CS2) properties of the vibration signal is investigated. Differently from previous works, the carrier frequencies (spectral content) of the gearmesh-cyclic CS2 components are analysed and used to distinguish and track the two wear phenomena. The effectiveness of the developed methods in wear mechanism identification and degradation tracking is validated using vibration data collected in two tests: a lubricated test dominated by fatigue pitting and a dry test dominated by abrasive wear. This development enables vibration-based techniques to be used for identifying and tracking fatigue pitting and abrasive wear.
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