In this study, the dry sliding wear behaviour of multiphase steels (MPS) was investigated with the help of a pin/ball-on-disc wear setup. The newly developed high strength and highly ductile MPS ...specimens consisting of various fractions of bainite, retained austenite, intercritical ferrite and pearlite, were obtained by a combination of continuous cooling for different times (0 s, 10 s, 20 s and 40 s) after austenitization followed by isothermal heat treatment at various temperatures (300 °C, 350 °C and 400 °C) for 10 min from a moderately high C (∼0.67 wt%) - high Si (∼1.71 wt%) steel. The worn-out surfaces and wear debris revealed that the primary material removal mechanism was of abrasive types. Wear scars were seen like a ploughed field-like structure. The depth of wear scars and amount of material collected at the periphery were affected by various phases and their fractions in the MPS specimens. The wear behaviour of the multiphase steels was affected by the distribution of plastic deformation due to continuous sliding of wear ball and application of loads on the surface of MPS specimens which was analysed by hardness variation of the sub-surfaces beneath the wear scars. At a particular austempering temperature, the wear volume loss and specific wear rate of the MPS specimens increased with the increase of continuous cooling time irrespective of the applied wear loads, and it was attributed to the formation of softer intercritical ferrite as well as pearlite formed due to longer continuous cooling. However, the bainitic structure formed by austempering without continuous cooling led to the highest wear resistance irrespective of the isothermal temperatures.
•Continuous cooling after austenitization followed by austempering makes various phase fractions in a high C high Si steel.•The varying fractions and distribution of multiphases lead to varying mechanical properties.•Multiphases and wear debris interactions control the wear of the multiphase steels.•Specific wear rate of multiphase steels increases with austempering temperature.•Specific wear rate of multiphase steels increases with continuous cooling time.
Squaring, a wood transformation process, is an operation which consists of introducing the logs into a squaring machine which then uses sharp tools to cut the wood into pieces with high surface ...quality. Tool steels used in this process experience significant wear, damaging the wood surface and hence leading to substantial scrape rate. This study investigates the wear resistance of three tool steels specifically designed for wood cutting applications: modified AISI A8, modified steels with 0% and 1% tungsten, and powder metallurgy prepared W360 steel. Furthermore, the influence of a PVD coating on the wear resistance of the three alloys was investigated. ASTM G65 abrasive wear tests were conducted using the dry sand/rubber wheel abrasion test. A methodology using a non-contact 3D measurement system and specialized software was developed, allowing for a thorough quantitative assessment of the wear of these steels. The results revealed that the coated A8mod + 1%W steel exhibits the best resistance among the coated steels. Despite the excellent intrinsic resistance of W360 steel, the coating did not provide a significant improvement for this steel, showing only a 10% reduction in wear. Microstructural analysis revealed that the predominant wear mechanisms were abrasion and impact. The relative performance of each steel was quantified and is reported. Field trials conducted under actual cutting conditions, indicate the superiority of W360 steel in terms of resilience to wear and impacts compared to other tested alloys, while confirming the effectiveness of surface treatments in mitigating material wear. However, A8 steel modified with 1% tungsten exhibits increased wear under coating.
Wear behaviour of quenched and tempered (QT) hot work tool steels (Uddeholm QRO90) was investigated against SAE 52100 grade bearing steel balls after gas nitriding using a dedicated laboratory scale ...impact-sliding wear test rig. Gas nitriding was employed in a fluidised bed reactor under two alternative regimes: i. “High Temperature Nitriding (HTN)” carried out at 510 °C and ii. “Low Temperature Nitriding (LTN)” carried out at ≤ 400 °C. The HTN process resulted in the formation of ∼2 μm thick external compound layer, whereas the LTN processed steels were free of any surface compound layer formation. After the impact-sliding wear tests employed at room temperature (RT), the prevailing wear mechanisms of the examined steels were assessed as tribo-oxidation and fatigue wear. The testing at 600 °C induced different wear mechanisms for the HTN and the LTN steels. While tribo-oxidation and fatigue wear were preserved for the HTN steel, plastic deformation dominated the wear that progressed on the compound layer free surface of the LTN steel. Impact-sliding wear testing at 600 °C showed that the wear rate of LTN > HTN steels, as opposed to the wear rate at RT where wear rate of HTN > LTN.
•Impact-sliding wear tests conducted on nitrided hot work tool steels.•Compound layer free steel exhibits comparatively high wear resistance at RT.•2 μm thick exterior compound layer provides higher wear resistance at 600 °C.
Wear and damage transitions of two kinds of wheel materials under different slip ratios conditions were explored using a rolling-sliding wear apparatus. Wear debris was analyzed using X-ray ...diffraction, Raman spectrometer and X-ray photoelectron spectroscopy. The results indicate that the evolution of wear rate of wheel materials can be divided into three regions: linear wear region, non-linear wear region and undefined wear region. The wear debris is mainly composed of Fe, Fe2O3 and Fe3O4. The relative content of Fe3O4 achieves a maximum value under the slip ratio of 12% condition. The transition from linear wear region to non-linear wear region is due to the wheel oxidation, while the transition from non-linear wear region to undefined wear region may be attributed to the formation of white-etching layer (WEL). A wear and damage mechanism mapping is constructed based on the wear and damage behaviors of wheel materials. Specifically, the dominant wear mechanism transforms from oxidative wear to fatigue wear and then changes back to oxidative wear with the slip ratio increasing.
•Three wear regions of wheel materials are identified (linear, non-linear and undefined wear region).•The behaviors of wear debris were characterized using various analytical methods.•Wear transition is caused by the oxidation or formation WEL of wheel materials.•A wear and damage mechanism mapping of wheel materials is constructed.
In this study, ceramic coatings were prepared on the surface of 7N01 aluminum alloy by micro-arc oxidation (MAO). The effects of NaAlO2 concentration in electrolyte on the thickness, roughness and ...bonding strength of micro-arc oxidation coatings were studied. The morphology, element distribution and phase composition of MAO coatings were analyzed by SEM, EDS, XRD and other analytical methods. The effect of MAO coating on the wear and corrosion resistance of 7N01 aluminum alloy were also studied, and the corresponding mechanism diagrams were established respectively. The results showed that with the increase of NaAlO2 concentration, the thickness of the coating gradually increased, the roughness decreased first and then increased, and the bonding strength rose first and then decreased. The sharp reduction of the mass loss rate and wear scar width indicated that the coating has good wear resistance. The wear mechanism was a mixture of abrasive wear and adhesive wear. Both the immersion test and the measurement results of the potentiostatic polarization curve showed that the coating has good corrosion resistance.
•NaAlO2 concentration can change coating thickness, roughness, bonding strength and micro morphology.•The coating can greatly improve the wear and corrosion resistance of 7N01 aluminum alloy.•The mechanism diagrams of wear and corrosion resistance are established.•Coating wear mechanisms include abrasive wear and adhesive wear.
In this study, the wear and corrosion characteristics of six-pass friction stir processed (FSPed) AA1050/mischmetal oxide nanocomposite (6PPA) was compared to six-pass FSPed sample without powder ...(6 PA) and annealed base metal (BM). Different wear characteristics, such as weight loss, wear rate and coefficient of friction (COF) were studied. In order to evaluate the corrosion resistance of samples, immersion and cyclic polarization tests were performed. In addition, worn and corroded surfaces were investigated by field emission scanning electron microscopy (FESEM). The result of pin on disk dry sliding wear test revealed that wear resistance improved by employing FSP through finer grain structure (6 PA sample) and by incorporation of mischmetal oxides (MMOs) through lubrication and load-bearing action of particles (6PPA sample). At the constant load of 30 N, COF decreased from 0.9 to 0.85 and 0.75, and weight loss from 7.4 to 5.7 and 4.5 mg/m × 10−3 for the BM, 6 PA, and 6PPA samples, respectively. According to FESEM study of the worn surfaces, the BM and 6 PA samples show an adhesive wear mechanism, however the wear mechanism changed to abrasive for 6PPA sample. Based on immersion test results, corrosion rate of BM reduced from 0.41 to 0.36 and 0.29 mpy for the 6 PA and 6PPA samples, respectively. Moreover, the results of cyclic polarization test and FESEM investigation showed improved pitting resistance of 6PPA sample.
Enhanced corrosion and wear performance of AA1050/mischmetal oxide nanocomposite, relative to friction stir processed sample without reinforcements and AA1050 base metal. Display omitted
•AA1050/Mischmetal oxide nanocomposite was fabricated by FSP.•Microhardness and UTS values of AA1050 were increased from 19 VHN and 60 MPa to 44 VHN and 132 MPa, respectively.•Incorporation of Mischmetal oxides decreased the COF and weight loss to 0.75 and 4.5 mg/m × 10−3, respectively.•Nanocomposite sample exhibited a corrosion rate of 0.29 mpy, in comparison with 0.41 mpy of AA1050.
•A systemic state-of-the-art review on vibration-based gear wear monitoring is presented.•The relationship between surface features and vibration characteristics is investigated.•Developments of ...vibration feature-based gear wear monitoring are summarized and discussed.•Developments of model-based gear wear monitoring are summarized and discussed.•Wear prediction techniques are reviewed.•Research prospects for gear wear monitoring are introduced.
Gearbox plays a vital role in a wide range of mechanical power transmission systems in many industrial applications, including wind turbines, vehicles, mining and material handling equipment, oil and gas processing equipment, offshore vessels, and aircraft. As an inevitable phenomenon during gear service life, gear wear affects the durability of gear tooth and reduces the remaining useful life of the gear transmission system. The propagation of gear wear can lead to severe gear failures such as gear root crack, tooth spall, and tooth breakage, which can further cause unexpected equipment shutdown or hazardous incidents. Therefore, it is necessary to monitor gear wear propagation progression in order to perform predictive maintenance. Vibration analysis is a widely used and effective technique to monitor the operating condition of rotating machinery, especially for the diagnosis of localized failures such as gear root crack and tooth surface spalling. However, vibration-based techniques for gear wear analysis and monitoring are very limited, mainly due to the difficulties in identifying the complex vibration characteristics induced by gear wear propagation. Understanding the effect of gear wear on vibration characteristics is essential to develop vibration-based techniques for monitoring and tracking gear wear evolution. However, no research work has been previously published to summarize the research progress in vibration-based gear wear monitoring and prediction. To fill the research gap, this review paper aims to conduct a state-of-the-art comprehensive review on vibration-based gear wear monitoring, including studying the gear surface features caused by different gear wear mechanisms, investigating the relationships between gear surface features and vibration characteristics, and summarizing the current research progress of vibration-based gear wear monitoring. This review also makes some recommendations for future research work in this area. It is expected that this review will provide useful information for further development of vibration-based techniques for gear wear monitoring and remaining useful life predictions.
Titanium alloys are widely used in many areas, such as aerospace, biomedical, and automotive industries, due to their excellent chemical and physical properties. However, its difficult-to-machine ...characteristic causes various problems in the machining process, such as serious tool wear and elastic deformation of workpieces. To achieve high efficiency and quality of machining titanium alloy materials, this paper conducted an experimental research on the high-speed milling of TC11 titanium alloy with self-propelled rotary milling cutters. In this paper, the wear mechanism of self-propelled rotary milling cutters was explored; the influence of milling velocity was analyzed on cutting process, and the variation laws with the change in milling length were obtained of milling forces, chip morphology, and machined surface quality. The calculation method of self-propelled rotary velocity was proposed, based on the experimental research. The results showed that in the early and middle stages of milling, the insert coating peeled off evenly under the joint action of abrasive and adhesive wear mechanisms. As the milling length increased, the dense notches occurred on the cutting edge of the cutter, the wear mechanism converted gradually into fatigue wear, and furthermore, coating started peeling off the cutting edge with the occurrence of thermal fatigue cracks on the insert. As the milling length was further extended, the milling forces tended to intensify, the chip deformation worsened, and the obvious cracks occurred at the bottom of chips. The increase in milling velocity intensified the friction between chips and self-propelled rotary milling cutters, and decreased the ratio of self-propelled rotary velocity to milling velocity. This caused the drop in cutting performance of cutters and the growth in tool wear rate.
The study aims to investigate the influence of environmental media on the friction and wear behavior of low-alloy wear-resistant steels and to provide practical references for their application. This ...article conducted sliding wear tests on NM500 wear-resistant steel under different loads under air atmosphere, deionized water, and 3.5 wt% NaCl solution conditions. Someone quantitatively measured the friction coefficient and wear amount of each friction pair. The present study employed scanning electron microscopy, energy dispersive spectroscopy, and a white light interference three-dimensional surface profiler to analyze the surface structure, cross-sectional morphology, element distribution, and wear mechanism of the wear scars under various experimental conditions. The results show that: In deionized water, NM500 has the best wear resistance, while the dry state is the worst. The lubricating and cooling effect of the liquid, as well as the corrosive effect of the NaCl solution, play an essential role in the wear behavior of NM500. Under dry friction conditions, the wear mechanism of NM500 is principally adhesive wear, fatigue wear, and oxidation wear. In the case of wear testing in deionized water, the researchers characterized the dominant wear mechanism as adhesive wear in conjunction with fatigue wear and abrasive wear. In contrast, when they carried out the wear testing in NaCl solution, the wear mechanism was primarily driven by corrosion wear and adhesive wear, with only a minor contribution from fatigue wear.
Coatings usually play an important role in terms of machining tool behaviour and lifespan. TiAlN is a well-known PVD coating but, the permanent need for improved performance is inducing new ...compositions around this coating. In this work, the wear behaviour of different PVD coated tools with different geometries was analysed, in the milling of pre-hardened tool steel. The selected tools had two different geometries, namely ball nose end mill and end mill tools. Additionally, these were coated with two different PVD coatings, TiAlSiN and TiAlN. These tools were employed in milling operations of W 1.2711 pre-hardened tool steel. The cutting parameters were defined in a way to enable a valid comparison between the milling tools, varying only feed and cutting length, to analyse the influence of these parameters on the tool's wear mechanisms. Cutting force data was collected during the milling tests using a dynamometer in order to identify the different wear stages of the tool, and surface roughness was measured after each test. Furthermore, after the milling tests the tools were submitted to a SEM analysis, in order to analyse the wear mechanisms of each coated tool. The main wear mechanisms that were identified in both coatings are adhesion and abrasion, followed by coating delamination. Moreover, the analysed wear was less significant in the TiAlSiN PVD coated tools used, mainly in the ball-nose tools, providing as well very good surface roughness of the machined surface. The surface morphology of the tool and the direction of the grooves left on the tool surface after grinding operations of the uncoated tool showed a significant influence on the coating wear mode. The best machining conditions have been established, taking into account the lowest surface roughness obtained on the machined surface and the lowest wear rate of the tool.
•TiAlSIN coating presented better results in pre-hardened tool steel milling than TiAlN coated tools (end-mill and ball-nose tools’ geometry).•Wear mechanisms follow this sequence: adhesion, abrasion, and delamination. The cycle is repeating itself, increasing systematically.•For the conservative set of parameters used, low machining forces were registered, and no significant variations were observed.•The first signals of tool failure happened after 2 m cutting length.•TiAlSiN coated tools provided lower roughness of the machined surfaces, showing a better suitability for finishing operations.•Best cutting conditions: 80 m/min cutting speed, 0.0147 mm/edge feed rate, 3 mm depth of cut under dry machining conditions.
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