Steel Disc Research Articles

Dry Sliding Wear Behavior of Cr-Al-N Diffusion Coatings against Silicon Nitride

In this study, the friction and wear behavior of uncoated and chromium aluminum nitride (Cr-Al-N)-coated AISI D2 tool steel disks were studied using a ball-on-disk system. Thermo-reactive diffusion technique was utilized to the coat desired phases onto pre-nitrided AISI D2 steel. The morphology and the phases formed on the coating layer were characterized by optical and scanning electron microscopy along with x-ray diffraction analysis. Friction and wear tests were conducted under atmospheric conditions with 2.5, 5 and 10 N loads at 0.1, 0.3 and 0.5 m/s sliding speeds against a silicon nitride ball. A dense and homogeneous coating layer with the thickness and hardness of 11.8 ± 1.3 µm and 2067 ± 160 HV0.01 was obtained. The results revealed that the friction coefficient values varied between 0.6-0.942 and 0.025-0.479 for uncoated and Cr-Al-N-coated AISI D2 steels, respectively. The wear rate of the uncoated and Cr-Al-N-coated AISI D2 steel fluctuated in the range of 5.01 × 10−4-3.47 × 10−3 mm3/m and 9.38 × 10−5-9.31 × 10−4 mm3/m, respectively. The wear rate of the Cr-Al-N coating was much lower than that of the AISI D2 steel.

Eriyik yığma modelleme ile üretilen PLA parçalarının kuru sürtünmeli aşınma davranışlarının tanılanması.

In this study, wear behavior of Poly Lactic Acid (PLA) parts manufactured by one of the additive manufacturing techniques Fused Deposition Modelling (FDM) is investigated and modelled via linear and non-linear identification. Transfer Function, Process Model and Nonlinear Autoregressive with Exogenous Input (NARX) model are used as modelling. Identified wear models are established according to wear tests conducted on Pin-on-disc test apparatus under constant load and constant sliding distance. Two different manufacturing orientations are chosen for the PLA pin specimens and wear tests are performed against steel and cast iron discs. Obtained results from the identified models are compared with the experimental results to select most efficient and reliable model structure.

Evaluation of Wear Properties of Heat-Treated Al-AlB2 in-situ Metal Matrix Composites

Considerable improvement in weight reduction, strength, wear obstruction, and modulus is the basic in meeting the plan and design criteria for the production of airplane, launch vehicles, and automobiles. This work proposes the low-cost manufacture process involving 2, 4, and 6 wt% AlB2 in-situ particle strengthened with aluminum (Al) Metal Matrix Composites (MMCs) utilizing chemical reaction through exothermic response between halide salt KBF4 and Al matrix at a temperature of 850 °C through vortex technique. The as-cast matrix blend and the in-situ composite were heat treated at a temperature of 535 °C for 1 h accompanied by quenching in various media like ice, oil, and water. The quenched samples were subjected to artificial aging at a temperature of 175 °C for 10 h. Microstructural studies were conducted on the as-cast and in-situ composites for dissemination of AlB2 particles in the as-cast matrix. SEM images affirm the development of AlB2 with uniform circulation in the matrix. X-ray diffractometer test was performed for the formation of AlB2 reinforcement phase in the matrix composite. Wear and mechanical properties were explored for the in-situ composites; for wear test, the impact of sliding rate, applied load, and sliding distance were basic parameters corresponding to the wear experienced by the material. The wear conduct and worn morphology of the aluminum MMCs subjected to various quenchants were additionally evaluated using pin-on-disc tests involving specimens to slide against a hardened steel disc under different load conditions. The exploratory outcomes exhibited that the typical load and fortification proportions were significant variables affecting the volumetric wear rate for all the quenched samples, trailed by sliding speed. The wear resistance behavior is found to be higher for specimens involving ice quenching treatment followed by water and oil-quenched composites.

Investigations of contact stresses and wear parameters for pin on disc using different pin materials

Wear component is an important factor influencing products service life which is based on material property and their behavior under given conditions. Therefore it is important to predict wear rate of components. In this paper we have discussed the wear parameters of pin on disc by varying pin materials. Numerical analysis was conducted on basis of load for different material components. When two bodies are in contact, contact pressure induces stresses in components.. Due to coefficient of friction, heat is generated between components. Hertz theory has been considered to determine the wear characteristic by using different pin materials on a steel disc. It was observed that aluminium alloy pin on steel disc generated low coefficient of friction, temperature rise and wear rate.

Design features of comminution disc and their relation with CO2 emission in disc life cycle

The structure of the comminution discs has the greatest impact on the comminution process efficiency and energy consumption and on the product fragmentation degree. Manufacturing, use and utilization of machine components carries environmental burdens in the form of emissions and energy consumption. The purpose of the work was to analyze the impact of the design features of the comminution disc (the construction material, the number and diameter of disk holes) on the amount of CO2 emissions in their life cycle. The 3D model of discs was made in SolidWorks and then an analysis of CO2 emission was made in Solid Works on the basis of the LCA and CM method. Sustainability was performed as well. It was found that energy consumption and CO2 emissions were higher for the life cycle of steel discs than those made of HDPE. Emissions of carbon dioxide during the life cycle of the working disk decrease along with an increase in the diameter and the number of holes. Regression equations describing the relationship between the diameter, number of holes in the disc and the amount of CO2 emissions in the life cycle were obtained on the basis of multiple regression analysis.

Effectiveness of topical adjuvants in reducing biofilm formation on orthopedic implants: an invitro analysis.

The treatment of periprosthetic joint infection is complicated by the presence of residual biofilm, which resists eradication owing to bacterial adherence to orthopedic implants. The purpose of this study was to compare Bactisure (Zimmer Biomet, Warsaw, IN, USA), povidone-iodine (Betadine), and chlorhexidine gluconate solution (Irrisept; Irrimax, Gainesville, FL, USA) in reducing biofilm formation of Staphylococcus aureus, Staphylococcus epidermidis, and Cutibacterium acnes inoculated on cobalt-chrome, titanium, and stainless steel disks, representing metals commonly used for shoulder arthroplasty. The hypothesis was that there would be no significant difference in biofilm reduction among the 3 topical adjuvants. Strains of S aureus (ATCC 35556), S epidermidis (ATCC 35984), and C acnes (LMG 16711) were grown on cobalt-chrome, titanium, and stainless steel disks. For each strain, the disks were divided into 4 groups: (1) control, (2) povidone-iodine (Betadine), (3) chlorhexidine gluconate (Irrisept), and (4) Bactisure. Bacteria were grown on 5% sheep blood agar plates. Biofilm eradication was quantified using adenosine triphosphate bioluminescence and compared with controls 48 and 72 hours after implementation of the topical adjuvant. At 72 hours after implementation of the topical adjuvant, a statistically significant reduction in colony-forming units was observed for all topical adjuvants across all tested metals, as compared with their respective control. With respect to the topical adjuvants themselves, Bactisure more consistently demonstrated the most significant reduction in colony-forming units across all bacteria when the tested medium was adjusted for, with the exception of S aureus, which showed similar results to Betadine at 72 hours. By use of commonly encountered topical adjuvants on S aureus-, S epidermidis-, and C acnes-inoculated disks of various implant metals, a significant reduction in biofilm production was observed. Bactisure, a recent Food and Drug Administration-approved topical adjuvant, demonstrated the overall greatest efficacy of the agents studied.

Effect of nozzle selection on deposition of thiamethoxam in Actara® spray drift and implications for off-field risk assessment

Off-target drift during pesticide spray applications represents a potential pathway for the introduction of active ingredient into field-adjacent water, soils, and/or vegetation. This study investigated the extent of downwind spray drift deposition of thiamethoxam (as a model insecticide) from an application of Actara® 25WG using standard nozzles (TeeJet XR11003, DG11004, and AIXR11002) onto a fallow field test site in the Midwestern USA. Single broadcast applications at a target rate of 96 g a.i./ha were made uniformly via tractor boom to a mowed stubble plot at a spray volume of 93.5 L/ha. Sampling devices (stainless steel disks, filter paper, and stainless steel rods) were located upwind of the spray swath (as negative control samples), within the spray swath (filter paper only), and downwind (all samplers), perpendicular to the spray swath from 12.5 to 400 ft. (3.8 to 122 m) from the edge of the treated field. Comparison of measured residues from the three types of samplers indicated that filter paper generally had greater variability in results than metal disks. When nozzles were compared, the AIXR11002 air induction nozzle produced less off-field deposition than other nozzles tested.Measured downwind concentrations of thiamethoxam from disk samplers were used to predict distances for mitigating potential effects to honey bees. Based on field-derived models, downwind distances from the spray swath required to reduce exposure levels below levels of concern for honey bees varied from <1 ft. to 148 ft. (0.3 to 45 m) depending on the hazard endpoint and nozzle used. These distances were considerably lower than those predicted using the AgDRIFT model, particularly for distances further downwind. At 400 ft. (122 m), AgDRIFT over-predicted the calculated concentrations by up to a factor of 4.8, 7.2, and 10 for DG11004, XR11003, and AIXR11002, respectively. These data suggest that the AgDRIFT model is less reliable for predicting spray deposition at further downwind distances, with implications for risk assessment.

Antibacterial Effect of Stainless Steel Surfaces Treated with a Nanotechnological Coating Approved for Food Contact.

Stainless steel, widely present in the food industry, is frequently exposed to bacterial colonization with possible consequences on consumers’ health. 288 stainless steel disks with different roughness (0.25, 0.5 and 1 μm) were challenged with four Gram-negative (Escherichia coli ATCC 25922, Salmonella typhimurium ATCC 1402, Yersinia enterocolitica ATCC 9610 and Pseudomonas aeruginosa ATCC 27588) and four Gram-positive bacteria (Staphylococcus aureus ATCC 6538, Enterococcus faecalis ATCC 29212, Bacillus cereus ATCC 14579 and Listeria monocytogenes NCTT 10888) and underwent three different sanitizing treatments (UVC, alcohol 70% v/v and Gold lotion). Moreover, the same procedure was carried out onto the same surfaces after a nanotechnological surface coating (nanoXHAM® D). A significant bactericidal effect was exerted by all of the sanitizing treatments against all bacterial strains regardless of roughness and surface coating. The nanoXHAM® D coating itself induced an overall bactericidal effect as well as in synergy with all sanitizing treatments regardless of roughness. Stainless steel surface roughness is poorly correlated with bacterial adhesion and only sanitizing treatments can exert significant bactericidal effects. Most of sanitizing treatments are toxic and corrosive causing the onset of crevices that are able to facilitate bacterial nesting and growth. This nanotechnological coating can reduce surface adhesion with consequent reduction of bacterial adhesion, nesting, and growth.

Acoustic emission and machine learning based classification of wear generated using a pin-on-disc tribometer equipped with a digital holographic microscope

The efficiency of processes involving frictional contacts between surfaces is often characterized by wear rates or friction coefficients. However, the classification and forecasting of wear rates in friction related processes is a real industrial challenge that is unsolved today. Hence, an on-line monitoring system able to classify wear rate can be crucial for many industries as it could help in preventing catastrophic failures. Applications include lifetime assessment of various industrial components where a range of wear failures occur such as scuffing (a typical sudden failure mechanism). These tribological processes can now be sensorized, and the corresponding sensor signatures can be modelled and monitored using state-of-the-art Machine learning (ML) algorithms. In this study, we use an Acoustic Emission (AE) sensor and ML frameworks to classify different wear categories simulated with a customized pin-on-disc tribometer. A real-time investigation of the wear track is necessary to find out the origins of the wear scar visible at the surface. To achieve this objective, the experiments were conducted on a pin-on-disc tribometer equipped with a Digital Holographic Microscope (DHM). Experiments were carried out using alumina and steel balls against steel discs at room temperature. Real-time DHM images of the wear track surface were recorded for each lap at the same position. An acoustic emission sensor recorded the AE signals during the complete duration of experiments. The AE signatures, in combination with the real-time DHM images, were correlated as input and ground truth labels for the ML algorithm. Several ML frameworks were compared; they are support vector machine, logistic regression, XGBoost, random forest, neural networks, k-Nearest Neighbor, quadratic discriminant analysis and Naive Bayes. The classifier was trained to differentiate the acoustic emission features of the different wear rates. Most ML algorithms had an average classification accuracy above 80%, and the highest was obtained with support vector machine (84.7%). The classification accuracy can be improved by combining two neighboring categories with limited differences in terms of wear rate. Hence, the proposed method has a significant industrial potential for in-situ and real-time quality monitoring of wear processes since it requires minimum modifications of commercially available industrial machines.

Phenomenological wear model of case-hardened 20MnCr5 under cyclic line rolling contact

Tribo-machineries employ machine elements, such as discs and gears, which are frequently subjected to Hertzian loads that cause their mechanical failure. Case hardening is a popular method that ensures better productivity and performance of such elements compared to its untreated variants. This paper presents a wear and fatigue model for case hardened steels under Hertzian loads in line contact. Steel discs with different case hardening depths were tested using a three-disc testing machine, and the samples were analyzed using optical microscopy, SEM and a portable X-ray diffractometer. The influence of type of contact, case hardening depths, normal force (contact stress) and slip conditions on the damage process are investigated in detail. It was found that the hardening layer should be adapted to the load, since a too large hardening depth means a shorter service life due to higher residual stresses gradients. The transferability of results to increase the service life of real-life components is an essential component of this work.

Investigation on tribo-characteristics of Calotropis gigantea fiber-reinforced-CNT modified polymer composites

This study included the preparation and tribo-characterization of Calotropis gigantea (CG) fiber reinforced CNT modified phenolic resin composites. Composites were prepared with varying contents (0.25, 0.5, 1 and 2 wt%) of multi-walled carbon nanotube (MWCNT) in phenolic resin, which was reinforced with CG fiber. The prepared composites were tested for their adhesive wear and frictional behavior at different applied loads (up to 100 N) against EN-31 steel disk on a standard pin-on-disk tribometer. The results revealed that addition of MWCNT enhanced the pressure–velocity (PV) limit significantly and reduced the value of friction coefficient of CG-fiber-reinforced phenolic resin composite. The friction coefficient decreases with increasing applied load. The wear rate significantly depends on MWCNT contents. The contact temperature of sliding surfaces increased with increasing applied load. The worn surfaces were analyzed and discussed to understand the wear mechanism involved with the help of SEM micrographs.

Effect of process parameters on dry centrifugal granulation of molten slag by a rotary disk atomizer

Dry centrifugal granulation (DCG) experiments for blast furnace slag (BFS) were performed by means of a rotary disk atomizer since water quenching method can create a series of problems. The results showed that the DCG method can granulate the BFS, but the results are easily affected by the slag flow rate, disk rotating speed, disk radius, disk material and slag falling height. The granulating parameters with an excessive flow rate, low rotating speed, SiN–SiC disk, stainless steel disk and low slag falling height are detrimental to the granulation process. The most suitable parameters for granulation are a slag flow rate of 5.1 × 10−5 m3/s, a disk rotating speed of 1500–2300 r/min, a slag falling height of 0.8 m and a smooth graphitic disk with the radius of 0.1 m. In the absence of an off-center flow, the overall best granulating effect produces round particles with mean diameter of 3.43 mm without creating slag fiber. The vitreous content of the BFS particles granulated by graphite disks is 92%, which meets the requirements of cement raw materials. The Bond work index of dry granulated BFS is 18.4 kWh/t, and the grindability of dry granulated slag and water-quenched slag is similar.

Tribological studies of glass filled Nylon 6 composites in self–mated contacts and against AISI D2 steel disc

Abstract In this experimental work, pin-on-disc set up were used to study the tribological behavior of Glass Filled (GF) Nylon 6 composite on polymer/polymer and polymer/ AISI D2 steel disc (SD) contacts under dry conditions. Load (N) and sliding speed (m/s) are the factors considered for the test and the output studied was Coefficient-of-Friction (COF), Specific-Wear-Rate (SWR) and heat generated at the contact zone. Ultra mild wear (at 4.9 N and 0.5 m/s) and severe wear (at 14.7 N and 1.5 m/s) is seen in the worn surface pin specimens of GF Nylon 6 pin/ SD combinations. Self-mated GF Nylon 6/GF Nylon 6 combination worn surface pin specimens exhibited moderate wear (at 4.9 N and 0.5 m/s) and ultra-severe wear (at 14.7 N and 1.5 m/s). The wear mechanism of the SD and polymer disc worn surface shows transfer layer and plastic deformation along the wear track, respectively. The COF and SWR have a close relationship with generation of heat and mechanisms of wear.

Phase composition and wear resistance of compacts and coatings based on carbides fabricated in W-Fe-C system by wet mechanical alloying

The paper reports on phase composition, microhardness and wear resistance of compacts and coatings based on η-carbides (Fe,W)6C and (Fe,W)12C produced by mechanical alloying of tungsten and iron powders in petroleum ether. The compacts have been prepared by magnetic-pulse compacting, and the coatings being formed on iron substrate by the selective laser sintering. The compacts exhibit microhardness up to 9.6 GPa and high abrasive wear resistance. Friction coefficients are 0.27-0.6 and 0.33-0.53 in frictional pairs with a steel disc and a ball made of WC-Co alloy, respectively, and wear not exceeding 10 µm in the tribo-pairs. The coatings have a microhardness of 16 GPa and friction coefficients of 0.28 and 0.2 for friction with balls made of steel and WC-Co, respectively, with no wear being practically observed in tribo-pairs. Combining the mechanosynthesis and selective laser sintering is shown to be very efficient to fabricate coatings based on η-carbides (Fe,W)6C and (Fe,W)12C possessing high values of hardness and wear resistance.

Study on influencing factors of unconfined penetration test based on orthogonal design

Tensile strength is one of the most important mechanical parameters controlling the development of cracks in loess plateau. The unconfined penetration test (UPT) is often used as an index for prediction of soil tensile strength properties. However, suffering the influence of the experiment condition, its uncertainty and sensitivity analysis to various experiment parameters was still unknown. Therefore, this study designed orthogonal tests and conducted the sensitivity analysis of influence factors (water content, dry density, steel disk (punch) diameter, height-diameter ratio, specimen preparation method, and loading rate) on the tensile strength of loess by using UPT. The statistical analysis of the test results indicated the order that affects tensile strength of the loess was water content, disk diameter, dry density, sample preparation method, height to diameter ratio, and loading rate respectively. The tensile strength of loess presented a tendency to increase at first and afterward to decrease as the increase of the punches diameter in UPT. The tensile strength reached a maximum value for a 24.72-mm disk diameter. According to the failure mode of the specimen, 12.3 to 20.5 times height-diameter ratio punches diameter range was considered appropriate. Furthermore, in the reconstituting specimen preparation method of disturbed loess, positive and reverse static pressure method was beneficial to the gain on the tensile strength. Maintaining a 1-mm/min loading rate, the variance of tensile strength was optimal. Moreover, the interactions of factors had significant effects on the tensile strength in UPT. The achieved results can provide the references and analytical analysis for standardizing UPT to measure the loess tensile strength.

Microstructure and Wear Behaviour of Matrix Al7075 Reinforced With Micro Wc-Co Particulate Composite Processed by Stir Casting Method

The present work dry sliding wear behaviour of Al7075 alloy matrix composite reinforced with 9Wt. % of WC-Co particulates is examined after prepared by stir casting. The dry sliding wear behaviour was studied for the composites with parameters of varying sliding speed, load and sliding distance. Microstructure characterization is done using SEM/EDX studies for the composite samples. From microstructural characterization even distribution of WC-Co particulates is observed in Al7075 matrix. DUCOM wear testing machine with EN32 steel disc is used to evaluate the wear rate of the composite. Worn out surface of the composite is subjected to SEM analysis to observe the layer formations. From the results of wear studies it is observed that the composite wear rate is reduced by restricting dislocation between the matrix and reinforcement interface.

Tribological properties of MoS2 thin films deposited by RF magnetron sputtering technique

This study aims to reduce the friction and wear losses of AISI440C steel, which is preferred in some machine elements like bearing balls, valves, oil pumps, cutters, springs, cams and scissors. The AISI440C substrates were coated with thin film MoS2 which provides low friction and wear. During the coating, steel disc groups were obtained by changing the parameters of deposition including the radio frequency sputtering power and the deposition temperature. The thickness value of the lubricating MoS2 films were determined with a scanning electron microscope. The hardness and elasticity modules of the MoS2 coatings were determined. The data showing friction coefficient-distance relation of wear tests was obtained and the average friction coefficients, wear amounts and wear trace widths were reached. In this way, how changes in substrate deposition temperature and RF sputtering power affect tribological properties were interpreted. As a result, tribological optimisation of the most suitable coating pair parameter was provided.

A systematic approach for the evaluation of wear characteristics of ZrO2 and AA6081 using Taguchi technique

Abstract This study investigates the wear properties of Aluminum Metal Matrix Composites (AMMCs) through Powder Metallurgy Technique (PMT). Three different Aluminum matrix composites reinforcements were undertaken for this experimental study. The Aluminium 6081 was reinforced with ZrO2 of various percentages. The percentages of reinforcement are varied from 2 to 6 wt%. The effect of load ranges from 20 to 40 N, sliding velocity ranges from 1.5 to 3.5 m/s and the sliding distance ranges from 700 to 2100 m on the wear behavior was tested on the EN 32 steel disc. Wear characteristics were investigated on a pin-on-disc apparatus. AA6081-2,4,6 vol% ZrO2, each was used as pin while the EN32 steel formed the rotating disc. This result was focused to examine the impact of composition, load and sliding speed on wear characteristics. The results show better wear resistance and also ANOVA response and regression are used to develop a model for the prediction of wear rate of the composites.

Self-absorption Correction Factors: Applying A Simplified Method to Analysis of Lead-210 in Different Environment Samples by Direct Counting of Low-energy Using HPGe Detector

This study aimed to determine the self-absorption correction factors of lead-210 (210Pb) in various Syrian environment samples. Seven sediments, five soils, and four plant samples were analysed by Gamma Spectroscopy using simple and direct analysis method called Cutshall. The method is based on measuring the penetration of gamma which emitted from a standard source, prepared in the laboratory by deposition of QCYB40 Standard Solution on stainless steel disk. The source was placed on top of the studied sample and the reference air sample during the measurement. The purpose was to study the self-absorption inside each sample by calculation of its self-absorption factors without knowing its chemical composition. The self-absorption correction results for the sediment samples SE3, SE6 and SE8 ranged between 36% and 45%, and 34% to 42% for the soil samples S5 and S1, respectively. Also, for the four plant samples, it recorded variance range from 4% to 18%. This is due to the difference in the density of the G4 sample, which appeared to be very low. However, the self-absorption correction factors CF were set for the different environmental samples, and the results show that the density factor of the sample is not the only influent factor in the CF values for low energies measurement, the sample chemical composition (sample matrix) is also more effective in addition to the samples’ particle sizes.

PROTECTIVE BEHAVIOR AGAINST CORROSION OF POLY(N-METHYLANILINE) COATINGS ELECTROSYNTHESIZED ON STAINLESS STEEL SURFACE FROM SULFURIC ACID CONTAINING MONOMER SOLUTION

Poly(N-methylaniline) coated stainless steel disc electrodes were obtained with N-methylaniline containing sulfuric acid solutions using constant potential, constant current and potentiodynamic techniques by electrodeposit method. Corrosion behavior of polymer coated electrodes were investigated by direct current (DC) polarization technique and linear anodic cyclic voltammetry in different aqueous (NaCl and HCl) solutions.