Steel Disc Research Articles

Study on microstructure and tribological property of aluminium-nickel composites fabricated by bottom pour stir casting

The present research explores the mechanical and tribological behaviour of Ni-reinforced aluminium composite. The aluminium alloy-1050 series has generally poor wear resistance. To enhance the wear resistance, a bottom pour stir casting method has been used to reinforce the hard Ni particles in the aluminium alloy at different weight percentages (6, 12, 18 wt%). As per the microstructural analysis, the manufactured base and composite materials have a polycrystalline structure. The peritectic reaction creates a hard intermetallic Al3Ni phase in the composites in terms of chemical reactions between the aluminium and Ni. XRD analysis has demonstrated the presence of the Al3Ni phase in the composites. The Al3Ni phase’s strong atomic bonding has enhanced the work of adhesion, hardness, and wear resistance. The dry sliding wear behaviour of the cast-AA and composites has been examined by a pin-on-disc instrument at different loads (20 and 40 N) against a hardened EN31 steel disc. The worn surface SEM images resulted in the following wear mechanisms: ploughing, adhesion, delamination, and abrasion. The CoF and wear debris size have been increased by increasing the load from 20 N to 40 N.

Water collection through a directional leaf vein pattern by fast laser marker ablation of stainless-steel

Inspired by the natural water harvesting mechanisms of desert beetles, cactus thorns, and leaf veins, we designed a heterogeneous wettability surface with superhydrophilic pattern integrating leaf vein as the directional water transport main channel, attached capillary triangles as auxiliary channel plus a deep rough desorption channel on an overall superhydrophobic surface for an efficient water collection. A superhydrophilic surface was initially fabricated on the stainless steel disc by laser marker ablation allowing 1 μL droplet to spread completely to 0° within 0.12 seconds, followed by fluorine-containing coating transforming superhydrophilic surface to superhydrophobic one. Directional water transport patterns were then etched on the superhydrophobic surfaces by the secondary laser marker. The surface energy gradient and Laplace pressure induced by the pattern facilitated directional fast transport and efficient desorption of droplets, thus improving water collection efficiency. The enhancement mechanism of the water harvesting behavior for such surfaces was analyzed, with one focus on enhancing collection in hydrophobic regions with capillaries to reduce bouncing off loss and the other on improving balanced cycling of the collection process. At a fog flow rate of 1500ml/h and 20cm away from the fog outlet, the directional leaf vein-patterned 19.625cm2 sized surface demonstrated a fog water collection rate (WCR) of 5.6 Kg·m-2·h-1 and first drop collection at the 49th s, an impressively short time rarely reported. Compared to the superhydrophobic, superhydrophilic samples, and the reference, WCR increased by 180%, 62%, and 59%, respectively, and the first droplet collection time decreased by 73%, 46%, and 62%, respectively. This efficient water collection method has huge potential in arid regions.

The tribological behavior of Cu-based brake materials against Cr3C2-NiCr coated steel disks with varying roughness

A high coefficient of friction (COF) and low wear rate are expected in the braking system for high-speed trains. For this purpose, we prepared coated steel disks by spraying Cr3C2-NiCr powders and slid them against Cu-based powder metallurgy pins. Pin-on-disk tests showed a significant increase in the COF with the Cr3C2-NiCr coated disk (roughness of 1.0 µm) reaching 0.514, compared to 0.366 for the uncoated steel disk. Additionally, there was a notable reduction in wear loss of the brake material, with the coated disk losing only 0.0088g, while the uncoated disk lost 0.0760g.The lower adhesion between the coating and the pin material, combined with the abrasive action of the harder coating on the disk surface, helps maintain the friction surface flat and virgin, thus avoiding the formation of thick friction films and fatigue cracks. As a result, a higher and more stable COF with lower wear was achieved when the coated disk slid against the pins.

Numerical simulation and experimental investigation on the thermal-fluid-solid multi-physical field coupling characteristics of wet friction pairs considering cavitation effect

The coupling characteristics of thermal-fluid-solid multi-physical fields are crucial in determining the operational performance and service life of wet clutches. However, the underlying mechanism behind the influence of cavitation effect on these coupling characteristics remains unclear. Therefore, we propose a numerical solution method for considering cavitation effect in the coupling characteristics based on the multi-physical field coupling platform MPCCI combined with ABAQUS and FLUENT. The distribution patterns and intercoupling relationships among temperature field, flow field, and stress-strain field are comprehensively analyze. The influence of relative speed, cross-sectional shape of oil grooves, and oil flow on the coupling characteristics is investigated. Experimental validation confirms that the proposed model accurately predicts temperature variation by accounting for cavitation effect. The temperature distribution of steel discs is notably affected by the cavitation effect, leading to an elevation in the maximum temperature and uneven distribution characterized by localized hot spots along the circumferential direction. Accounting for the cavitation effect reduces errors between calculated and experimental values of temperature rise. The convective heat transfer coefficient gradually decreases radially, with a more pronounced decrease in the cavitation region. An increase in relative speed and a decrease in oil flow both lead to greater cavitation volume, resulting in higher temperature of steel discs. Among three different cross-sectional shapes of oil grooves investigated, rectangular grooves exhibit larger areas affected by cavitation compared to triangular grooves. These research findings provide a theoretical basis and technical support for accurate prediction of thermal characteristics within high-power wet clutches.

Enhanced tribological properties of sliding contacts through the synergistic effect of PTFE film and PSAIL 2280

PurposeThe purpose of this study is to investigate the effectiveness of a composite lubrication system combining polytetrafluoroethylene (PTFE) film and oil lubrication in steel–steel friction pairs.Design/methodology/approachA PTFE layer was sintered on the surface of a steel disk, and a lubricant with additives was applied to the surface of the steel disk. A friction and wear tester was used to evaluate the tribological properties and insulation capacity. Fourier transform infrared spectrometer was used to analyze the changes in the composition of the lubricant, and X-ray photoelectron spectroscopy was used to analyze the chemical composition of the worn surface.FindingsIt was found that incorporating the PTFE film with PSAIL 2280 significantly enhanced both the friction reduction and insulation capabilities at the electrical contact interface during sliding. The system consistently achieved ultra-low friction coefficients (COF < 0.01) under loads of 2–4 N and elucidated the underlying lubrication mechanisms.Originality/valueThis work not only confirm the potential of PTFE films in insulating electrical contact lubrication but also offer a viable approach for maintaining efficient and stable low-friction wear conditions.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-06-2024-0222/

Application of the electrical impedance method to steel/steel EHD point contacts

The authors have previously developed the electrical impedance method which simultaneously measure the thickness and breakdown ratio of oil films in EHD (elastohydrodynamic) contacts. Furthermore, using a ball-on-disc-type apparatus, the authors have also confirmed that the accuracy of oil film measurement by the developed method is comparable to that of optical interferometry (i.e., glass-steel contacts). In this study, we discussed the experimental results obtained by applying the electrical impedance method to steel-steel contacts using a steel disc instead of a glass disc. It was found that under the mixed lubrication regime where wear occurs, the oil film thickness obtained by this method is calculated to be significantly thicker than the theoretical value. This can be attributed to the increase in the apparent dielectric constant of the lubricant due to wear particles in the lubricant.

Evaluation of Pore-Former Size and Volume Fraction on Tape Cast Porous 430 Stainless Steel Substrates for Plasma Spraying.

Porous 430L stainless steel disks made by tape casting with various pore-former sizes and volume fractions were evaluated as substrates for solid oxide cell (SOC) fabrication by plasma spraying. This work reports the substrate properties relevant to the SOC operation of disks made by using extra fine metal powder with dense sintering to minimize the fine porosity between particles. In contrast, the coarse porosity is introduced by the pore former. We found that the 60 μm pore former at a 45 vol% fraction has the best application fit; it gives an adequate gas permeability of 3.11 × 10-13 m2 and an average open pore size of 45.90 μm. Compared to a commercial substrate with a similar porosity perimeter/steel area ratio, the porosity and gas permeability are 1.6 and 3 times higher, respectively. The detected maximum surface pore is 49 μm, allowing gas-tight electrolytes fabricated by plasma spray deposition.

A comparative study on tribological and mechanical behavior of as-cast and aged Mg-6Gd-2Ag-0.6Zr alloy at elevated temperatures

The effects of aging treatment on the mechanical and tribological behavior of Mg-6Gd-2Ag-0.6Zr alloy were investigated. Shear punch testing and hot hardness measurements were conducted to evaluate the mechanical properties of the alloys at various temperatures of 25–350 °C. The aging treatment enhanced the mechanical behavior of the alloy, resulting in increases in hardness and ultimate shear strength by about 53–64% and 11–22%, respectively, at various temperatures. Dry sliding wear tests were carried out under the normal loads of 5, 20, 40, and 60 N within a temperature range of 25–325 °C using a Pin-on-disk tribometer against AISI52100 steel disks. Despite the improvements in mechanical properties, the aging treatment reduced wear resistance by about 45% under a normal load of 5 N at various wear temperatures. However, as the normal load was increased to 60 N the aged alloy showed about 11–23% lower wear rate at various temperatures. The characterization of the wear surfaces also showed that the oxidation wear became more dominant as the normal load and the wear temperature increased. Under higher normal loads of 40 and 60 N, a 54–88% greater transfer of magnesium oxides was observed on the steel disk, which reduced the contact between the steel disk and the magnesium alloy pin.

RESEARCH PROGRESS ON STRENGTHENING PROCESS OF H13 STEEL FOR SHIELD CUTTER RING

As China continues to advance the modernization process, a large number of infrastructure construction projects need to use shield machines to build tunnels. As a key component of the shield machine/TBM direct contact working environment, the hob is extremely complex and extremely harsh due to the extremely complex and extremely harsh working environment, resulting in hobs. It is very easy to damage when in service. The damage of the hob directly leads to many problems such as project delay and capital consumption. Therefore, improving the mechanical properties of the hob and prolonging the service life is an important engineering problem to be solved urgently. Based on the service performance of disc cutter, this paper analyzes its failure form and wear mechanism, and summarizes the strengthening process and improvement method of the H13 steel disc cutter ring. In this paper, the advantages and disadvantages of previous researchers and optimization methods are reviewed for H13 steel material composition, heat treatment process, surface coating strengthening process, and other processes. Finally, the performance strengthening of hob cutter ring is discussed and prospected, in order to provide a reference for hob strengthening technology path and industrialization realization.

Methylcellulose-functionalized gallium-based liquid-metal nanoparticles as water-based lubricant additives

Ga-based liquid metal nanoparticles (GLM-NPs) are a novel high-performance additive for lubricants and this work novelty prepared a novel type of heterogeneous nanoparticles modified with a cost-effective and available methylcellulose (GLM-NPs/MC). It displays a clear core-shell structure with a particle size of about 270 nm, and as a water-based lubricant additive, it exhibits good tribology properties, reducing the friction coefficient and wear rate of the 304 steel discs by about 59 % and 40 % respectively. The high dispersion and good stability of GLM-NPs/MC make them slowly enter into the worn surface to form a Ga-rich tribo-film. In addition, the influence of GLM-NPs/MC content on the lubrication performance of the water was also studied and the optimization additive content is 0.6 wt%. This study provides insights into the design of nano-composite materials based on gallium-based liquid metal for lubrication applications.

Effect of the infill percentage of 3D printed Polyetheretherketone under the dry sliding condition

Sliding bearings made of advanced polymers like Polyetheretherketone (PEEK) are preferred for medium and heavy-duty applications. The high-temperature additive manufacturing process permits the efficient fabrication of lighter porous parts using high-cost materials like PEEK. Customised geometries and surface features are easily achievable using an additive manufacturing process and facilitate design for the required performance. The 3D-print parameters employed affect the surface characteristics and are investigated. The variation in infill porosity is found to affect the crystallinity, hardness, modulus, and surface roughness of the printed samples. The friction coefficient variation, wear resistance, and temperature rise in the 3D-printed PEEK samples are studied when slid against steel discs under dry sliding conditions. The material transfer between surfaces varies based on the sample's surface properties and porosity, significantly affecting friction and wear behaviour. Accumulation and strong adhesion of wear debris in the groves of PEEK samples contribute to improved wear resistance. The temperature rise in the polymer sample also depends on the infill porosity, and a reduced temperature rise is observed in porous samples, which will improve the life when used in bearings.

Evaluation of tribological parameters for boron carbide and graphite infused aluminium hybrid composite fabricated by stir casting technique

The present work focuses on suggesting Gr as a valuable self-lubricating reinforcement for hybrid composite samples and offering a minimum wear rate for sliding pairs with fewer mechanical surface defects at the same time. A series of samples were fabricated using the route by stir casting method considering B4C and Gr as the two reinforcements. The morphology of the sample has been studied using the X-ray diffraction graphs, Energy dispersive X-ray analysis and Scanning electron imaging stating the homogeneity of reinforcement in various composite cast. The theoretical and experimental density of the series of samples has been studied and compared stating the low porosity of the samples fabricated. A maximum wear rate (Wr) of 0.351 × 10−4 mm3/m. was found for pure aluminium sample against EN31 steel disc with 0.053 as friction coefficient (µ). Wr was somehow seen to reduce up to 0.286 × 10−4 mm3/m for Al-B4C composite with µ of 0.48. For hybrid samples, the wear rate was further seen to improve to 0.187 × 10−4 mm3/m for Al-B4C and Gr 2.0% weight with µ of 0.38. Least Wr was found for composite having Gr 3.5% weight, of 0.149 × 10−4 mm3/m. with µ of 0.36. SEM images of the worn surface give evident results for delamination and crack formation on the pin face for the pure-Al sample. Taguchi-ANOVA analysis has been carried out showing the valid contribution of pin type, load and sliding speed on Wr and friction coefficient as the P-value lies below 0.05 for input parameters considering the 95% confidence level of the model developed. An F-value of 44.57 with R2 of 0.895 is developed for Wr model and an F-value of 54.2 with R2 of 0.934 for the µ model.

Mechanical Properties and Tribological Study of Bottom Pouring Stir-Cast A356 Alloy Reinforced with Graphite Solid Lubricant Extracted from Corn Stover

The present work epitomises extracting the graphite (Gr) solid lubricant from the corn stover. The extracted Gr was incorporated as reinforcement in the A356 alloy (Al-7Si), and the effect of the Gr particles on the mechanical and tribological properties was investigated. In spite of this, the input process parameters for the dry sliding wear test at room temperature against the EN31 steel disc were optimised through ANOVA analysis. The fabricated A359—X wt% (X = 0, 2.5, 5, 7.5) composite through bottom pouring stir casting techniques was analysed microstructurally by using XRD and FESEM analysis. The micro Brinell hardness and tensile strength were investigated per ASTME10 and ASTME8M standards. A wear test was performed for the composite pins against the EN31 steel disc according to ASTM G99 specifications. The XRD analysis results depict the presence of carbon (C), aluminium (Al), and silicon (Si) in all the wt% of the Gr reinforcement. However, along with the elements, the Al2Mg peak was confirmed for the A356—7.5 wt% Gr composite and the corresponding cluster element was confirmed in FESEM analysis. The maximum micro Brinell hardness of 92 BHN and U.T.S of 123 MPa and % elongation of 7.11 was attained at 5 wt% Gr reinforcement due to uniform Gr dispersion in the A356 alloy. Based on the ANOVA analysis, the optimal process parameters were obtained at 20 N applied load, 1 m/s sliding velocity, and 1000 m sliding distance for the optimal wear rate of 0.0052386 g/km and 0.364 COF.

Characterization and tribological performance of new epoxy coatings modified with sustainable ionic liquid-graphene nanolubricants

Graphene-based nanolubricants were prepared using the environmentally friendly 2-hydroxyethylammonium lactate (ML) ionic liquid. The Graphene-ML dispersion (MLG) and neat ML were added to Epoxy Resin (ER) in 5 and 10 wt% proportions to study the effect on the curing conditions by means of Differential Scanning Calorimetry (DSC) and oscillatory rheology. A nucleating effect was found for Graphene, while ML presented a plasticizing effect. These findings were confirmed by DSC and Dynamic-Mechanical Analysis (DMA) with a decrease on the mechanical properties and glass transition temperature. ML and MLG were evaluated as external lubricants of epoxy coatings, finding outstanding friction and wear prevention ability. One and two layer ER coatings were deposited on AISI 1015 steel disks. When used as internal lubricant, MLG is able to prevent surface damage on bi-layer ER coatings. Therefore, we provide a novel approach for the preparation of ER composites with environmentally friendly nanolubricants for applications under demanding conditions.

Passive wireless multi-parameter LC sensing system for in situ health monitoring of bearings

The health condition of bearings is crucial for the safe operation of equipment. In situ, multi-parameter monitoring of the rotating components of bearings facilitates accurate assessment and diagnosis of bearing health. Based on the previous research on LC (Inductor-Capacitor) strain sensor for bearings, a passive wireless multi-parameter LC sensor suitable for in situ monitoring of bearings is proposed. The LC sensor uses dual resonance frequencies together with one quality factor to simultaneously monitor three parameters of bearing. Theoretical derivation and simulation analysis indicate that, due to the adoption of a symmetrical circuit structure, the two resonant frequencies of the LC sensor are independent and do not interfere with each other. Furthermore, the asymmetric analysis shows that under significant parameter asymmetry, the two resonant frequencies still maintain excellent independence. According to the installation position of the bearing, the sensor coil and the sensor circuit are designed to be conformal to the bearing. The acceleration, strain and temperature response curves of the LC sensor are measured by installing it on a circular steel disc that simulates the environment of a bearing. Finally, the LC sensor is successfully demonstrated on a bearing test platform.

Dry Sliding Wear Behavior of Cemented Carbide at Elevated Temperatures

The material for a cutting tool needs to be carefully selected to withstand high temperatures during cutting and have good wear performance. The use of cutting tools made from cemented carbide material was studied due to its potential in terms of mechanical properties that are ideal at high temperatures up to 1000 °C and being cheaper than other materials. This investigation of the dry wear of this cutting material focused on temperatures of 25 °C, 200 °C, and 300 °C, with loads of 50 N, 100 N, and 150 N. The weight loss, friction coefficient, and change of the pin microstructure were determined. It was found that the higher the temperature and load applied to the cemented carbide pin, the more the microstructure changed, and the percentage of weight loss increased up to 0.55%. The wear rate on the cemented carbide pins was higher when applied to a stainless steel disc compared to a mild steel disc. The simulation revealed that the von Mises stress on the stainless steel disc was 51.759 Pa, while that on the mild-steel disc was 60.379 Pa. This indicates that both materials did not fail because the von Mises stress was lower than the disc yield stress.

Investigation of the solid self-lubricating effect on tribological properties of Al/SiC/Gr composites against steel disc

Investigation of the solid self-lubricating effect on tribological properties of Al/SiC/Gr composites against steel disc

Evaluation of an automated far ultraviolet-C light technology for decontamination of surfaces and aerosolized viruses in bathrooms

BackgroundAerosols generated during toilet flushing are a potential source for transmission of viral and bacterial pathogens in bathrooms. However, manual decontamination of bathrooms after each use is not feasible.MethodsWe tested the efficacy of a wall-mounted far ultraviolet-C (UV-C) light technology that only delivers far UV-C when people are not present for decontamination of surfaces and aerosolized viral particles in an unoccupied hospital bathroom. A quantitative disk carrier test method was used to test efficacy against organisms on steel disk carriers placed in 9 sites in the bathroom with an exposure time of 45 min and 2 h; Clostridioides difficile spores were also exposed for 24 h. Efficacy against aerosolized bacteriophage MS2 was tested with a 45-minute exposure.ResultsThe far UV-C technology reduced methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), Candida auris, and bacteriophage MS2 on steel disk carriers by ≥ 1.2 log10 (range, 1.2 to 4.2 log10) at all test sites after 2 h of exposure. The technology reduced C. difficile spores by < 1 log10 after 2 h exposure, but 4 of 9 test locations had ≥ 2 log10 reductions after 24 h exposure. Aerosolized bacteriophage MS2 was reduced by 4 log10 plaque-forming units in 45 min.ConclusionsThe far UV-C light technology could potentially be useful for automated decontamination of air and surfaces in bathrooms in healthcare and community settings.

A far ultraviolet-C light technology is effective for decontamination of items in proximity to sinks and is enhanced by a far UV-C reflective surface.

Dispersal of gram-negative bacilli from sink drains has been implicated as a source of transmission in multiple outbreaks. In an acute care hospital, we assessed how often patient care supplies and other frequently touched items were within 1 meter of sink drains. We tested the efficacy of a ceiling-mounted far ultraviolet-C (UV-C) light technology for decontamination of sink bowls and surfaces near sinks with and without a wall-mounted film that reflects far UV-C light. Of 190 sinks assessed, 55 (29%) had patient care supplies or other frequently touched items within 1 meter of the drain. The far UV-C technology reduced Pseudomonas aeruginosa, Enterobacter cloacae and Candida auris on steel disk carriers by ≥1.5 log10 colony-forming units (CFU) in 45 minutes. On inoculated real-world items, ≥1.9 log10 CFU reductions in P. aeruginosa were achieved on sites in line with the light source versus 0.4-1.8 log10 CFU reductions on shaded surfaces. The addition of the reflective surface significantly enhanced efficacy in shaded sites (P < 0.01). In a hospital setting, patient care supplies and other frequently touched items were often in proximity to sinks. The far UV-C light technology could potentially be useful for sink decontamination in high-risk areas.

Dry sliding wear characteristics of hybrid aluminum alloy with nano-fly ash and nano-yttrium oxide

Aluminum alloys feature impressive levels of strength, ductility, castability, wear resistance, and corrosion resistance, making them highly advantageous for the aviation and automotive industries. This study investigates the dry wear performance of hybrid nanocomposites (HNCs) produced using Al6061 as the matrix, with nano-fly ash (FA) and nano-yttrium oxide (Y2O3) as reinforcing agents, utilizing the stir-casting method. The weight percentage (wt-%) of FA was fixed at 4 wt-%, while the Y2O3 varied from 1 wt-% to 3 wt-%. The specimens were prepared following ASTM-G99 standards and tested using a pin-on-disc apparatus with an E31 steel disc under four different loads: 10 N, 20 N, 30 N, and 40 N. It has been observed that wear rate has been increased with the increase in the applied load. The maximum wear rate has been recorded for the base Al6061 alloy as 5.63 × 10−4 mm3/N-m at 40 N load due to its lower wear resistance and less hardness value. The addition of reinforcement particles in the base alloy results in the grain refinement and improvement in the load-bearing capacity. It has been found that at 40 N load, the Al-6061 alloy reinforced with (4 wt-% FA + 3 wt-% Y2O3) is 56.83% superior in terms of wear resistance (2.43 × 10−4 mm3/N-m) as compared to Al6061 base alloy. The hybrid nano-composite containing 4 wt-% FA + 3 wt-% Y2O3 showed the highest value of microhardness as 123.2 HV, which is 136% higher than that of base alloy due to the higher load-bearing characteristics of the reinforcement particles. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) have been employed to analyze both unworn and worn surfaces, revealing uniform dispersion of reinforcement particles, the formation of an oxide layer, micro-pitting, wear debris, and material delamination. Grain refinement has been examined using the line intercept method (ASTM E1382-97), and X-ray diffraction (XRD) confirmed the elemental composition of the nano-reinforcements.