Erosion Wear Rate Research Articles

Erosion Wear Analysis of Plasma Sprayed Ceramic Coating Using the Taguchi Technique

Erosion wear behavior of fly ash–illmenite coating was studied using dry silica sand as an erodent. A plan of experiments based on the Taguchi technique was used to acquire the data in a controlled way. An orthogonal array and signal-to-noise ratio was employed to investigate the influence of the impact angle, the velocity, the size of the erodent, and the standoff distance (SOD) on erosion wear. The objective was to investigate which design parameter significantly affects the erosion wear. It was found that the impact angle is the most powerful factor influencing the erosion wear rate of the coating. Further, when erosive wear behavior of fly ash–illmenite coating was investigated at three impact angles (i.e., at 30°, 60°, 90°), it was revealed that the impact angle is the prime factor and maximum erosion takes place at α= 90°.

An Investigation on Erosion Wear Characteristics of SiC Particle Reinforced Steel Matrix Surface Composite

The erosion wear characteristics of SiC particles reinforced steel matrix surface composite were studied by self-made slurry erosion wear test apparatus with quartz slurries, and contrasted with that of plain carbon steel, high chromium cast iron and low chromium cast iron. The results indicated that the erosion wear rate of the four tested materials has the different changes not only with the quartz particles sizes in slurry, but also with the erosion angle of slurry. The erosion wear rate of SiC particle reinforced steel matrix surface composite is the lowest in four kinds of tested materials under the test conditions. And that of high chromium cast iron is less than that of low chromium cast iron under the same test conditions. The SiC particles embedded the steel matrix could prevent the steel surface from wear brought by quartz particles in slurry erosion wear, and protect the steel matrix, so that the erosion wear resistance of steel matrix could be increased.

Wear Mechanisms at High Temperatures: Part 2: Temperature Effect on Wear Mechanisms in the Erosion Test

In previous investigations on wear mechanisms at high temperatures made in High Temperature-Single Impact Test (HT-SIT) and High Temperature-Continuous Impact Abrasion Test (HT-CIAT), predominant wear mechanisms were identified and correlations to different material parameters could be presumed. In order to confirm these correlations, four different alloys which are promising to be used in high temperature applications like a sinter grate have been studied in the High Temperature-Erosion Test (HT-ET) by the use of different impact angles and different impact energies. Especially the change of wear mechanism caused by increasing testing temperature was analysed in detail. Characterisation of microstructure and wear behaviour has been done by optical microscopy (OM) and scanning electron microscopy (SEM). Results obtained by the use of the different measurement techniques were linked and set into comparison to calculate the volumetric wear of the specimen. Predominant wear mechanisms were determined using OM in the mode of cross-section images and SEM. The results indicate that material parameters such as hardness and hard phase content can be correlated to the erosion wear rates at different impact angles. The test results indicate that at higher temperatures, the material fatigue becomes a major wear-determining factor. The test results also confirmed that there is a critical impact energy for each material above where the wear rate increases significantly. Test results with thermally aged materials also show that a better heat-resistant matrix reduces the material fatigue thus resulting in lower wear rates.

Influence of heat treatment on slurry erosive wear resistance of Al6061 alloy

Material loss due to slurry erosion is a serious problem in many industrial applications like hydraulic turbines, slurry pumps, pipe lines, etc. where the ideal choice of engineering materials is a real challenge. Light weight aluminum alloys are finding wide applications in the field of aerospace, automobile, defence, etc. due to improved physical, mechanical and tribological properties. Among all available alloys Al6061 is extensively used owing to its reasonable strength and ease of processing. Currently these alloys are also explored as candidate materials for propeller blade of torpedoes where major failure occurs due to slurry erosive wear. In the light of the above present investigation is aimed to study the slurry erosive wear behavior of heat treated Al6061 alloy in 3.5%NaCl solution with sand particles slurry. The studies were carried out at different sand concentration (10–40%), varying rotational speed (500–1500 rpm), at different time duration (5–25 h) and varied impinging particle size (100–600 μm). The effect of heat treatment on erosive wear behavior of Al6061 alloy were studied by subjecting to solutionising at temperature of 530 °C for a duration of 2 h, followed by quenching in air, water and ice media. Both natural and artificial aging at 175 °C was performed on quenched samples from 4 to 10 h duration in steps of 2 h. The rate of material loss is found to be higher with increased sand concentration due to increased impinging action of sand particles. Increased speed of slurry rotation increases the velocity of impingement of sand particles on the surface of erodent and resulted in higher weight loss. Increased time duration up to 20 h, the wear rate increases. However, beyond this test duration, the wear rate attains a steady state with further increase in test duration. It is found that heat treatment has profound effect on slurry erosive wear resistance of Al6061 alloy. It is also observed that with increase in aging duration for all quenching medias studied there is a reduction in slurry erosive wear rate. However, ice as quenching media offers higher erosive wear resistance compared to water, air and unheat treated alloy. SEM studies were carried out on eroded surface to observe the mechanism of metal removal. The eroded surface also indicates that increased sand concentration, higher rotational speed and increased particle size resulted in severe damage on tested surfaces.

331 長繊維強化複合材料のエロージョン損傷機構に及ぼす投射条件の影響(摩擦・摩耗材料)

The present study describes effect of impact media size on erosive wear mechanisms of woven continuous SiC fiber reinforced ceramic matrix composites (CMC). The CMC was processed by chemical vapor infiltration (CVI) and consisted from fibers having 10 μm of mean diameter. Various size of green silicon carbide (SiC) abrasives used for the impact media were collided to the target CMC surface with pressurized air. Results showed that erosive wear rate and crack pass were different depend on the media size. A relationship between the crack pass and the erosive wear rate analyzed with the present erosive wear model based on the lateral crack extension.

Microstructure, Adhesion, and Erosion Wear of Plasma Sprayed Alumina-TitaniaComposite Coatings

Plasma spray technology is being widely used for the development of protective coatings to prevent degradation of critical components working under severe conditions. Plasma sprayed alumina-titania have many industrial applications. These coatings provide a dense and hard surface which is resistant to abrasion, corrosion, cavitation, oxidation, and erosion. Plasma sprayed alumina-titania coatings are regularly used for wear resistance, electrical insulation, thermal barrier applications, etc. Alumina pre-mixed with titania powder is deposited on mild steel substances by atmospheric plasma spraying. Microstructure of the coating is analyzed by SEM. Adhesion strength of alumina-titania coatings are measured. The response of plasma sprayed alumina-titania coatings to the impingement of solid particles has been presented in this study. The erosion rate is calculated on the basis of 'coating mass loss'. It is observed that the erosion wear rate varies with erodent dose, angle of attack, the velocity of erodent, standoff distance, and size of the erodent. Cumulative coating mass loss varies with time of erosion.

A Taguchi Approach for Investigation of Erosion of Glass Fiber — Polyester Composites

Polyester composites reinforced with three different weight fractions of woven E-glass fiber reinforcement are developed. To study the effect of various operational and material parameters on erosive wear behavior of these composites in an interacting environment, erosion test are carried out. For this purpose, an air jet type erosion test rig and the design of experiments approach utilizing Taguchi's orthogonal arrays are used. The findings of the experiments indicate that erodent size, fiber loading, impingement angle and impact velocity are the significant factors in a declining sequence affecting the wear rate. Significance of erosion efficiency in identifying the wear mechanism is highlighted. It is confirmed that the glass-reinforced-polyester composites exhibit mostly semi-ductile erosion response. An optimal parameter combination is determined, which leads to minimization of erosion rate. Analysis of variance (ANOVA) is performed on the measured data and signal to noise (S/N) ratios. A correlation derived from the results of Taguchi experimental design is proposed as a predictive equation for estimation of erosion wear rate of these composites. It is demonstrated that the predicted results obtained using this equation are consistent with experimental observations. Finally, optimal factor settings for minimum wear rate are determined using genetic algorithm.

An Investigation of the Erosion Wear of Pitched Blade Impellers in a Solid-Liquid Suspension

This paper reports on a study of the erosion wear mechanism of the blades of pitched blade impellers in a solid-liquid suspension in order to determine the effect of the impeller speed n as well as the concentration and size of the solid particles on its wear rate. A four-blade pitched blade impeller (pitch angle α = 30°), pumping downwards, was investigated in a pilot plant fully baffled agitated vessel with a water suspension of corundum. The results of experiments show that the erosion wear rate of the impeller blades is proportional to n2.7 and that the rate exhibits a monotonous dependence (increase) with increasing size of the particles. However, the erosion rate of the pitched blade impellerreaches a maximum at a certain concentration, and above this value it decreases as the proportion of solid particles increases. All results of the investigation are valid under a turbulent flow regime of the agitated batch.

Study of the strength and erosive behavior of CaCO3/glass fiber reinforced polyester composite

In this study, the strength and erosive characteristics of CaCO3 filled unsaturated polyester/glass fiber (UPR/GFR) composite are evaluated. Samples of UPR with 40, 50 and 60 wt% content of CaCO3 and different CaCO3 par- ticle sizes of 1, 2, 3, 5 and 10 micron were prepared and tested under tensile loading, indentation and erosion conditions. The tensile strength, hardness and erosion wear rate of unsaturated polyester/glass fiber (UPR composite)/CaCO3 compos- ite were obtained and evaluated. The results showed that the higher is the percentage of CaCO3 in the composite and the smaller is the CaCO3 particle size, the higher is the strength and the erosive resistance of the glass fiber reinforced/unsatu- rated polyester composite (UPR-GFR). Furthermore, the highest erosion wear rate is at 90° impingement angle. Finally the results show that the erosive wear of CaCO3 content UPR/GFR composite in a brittle manner.

Taguchi method applied to parametric appraisal of erosion behavior of GF-reinforced polyester composites

Polyester composites reinforced with three different weight fractions of woven E-glass fiber reinforcement are developed. To study the effect of various operational and material parameters on erosive wear behavior of these composites in an interacting environment erosion tests are carried out. For this purpose, air jet type erosion test rig and the design of experiments approach utilizing Taguchi's orthogonal arrays are used. The findings of the experiments indicate that the rate of erosion of composites by impact of solid erodent is greatly influenced by the control factors. An optimal parameter combination is determined, which leads to minimization of erosion rate. Analysis of variance (ANOVA) is performed on the measured data and S/N (signal to noise) ratios. A correlation derived from the results of Taguchi experimental design is proposed as a predictive equation for estimation of erosion wear rate of these composites. It is demonstrated that the predicted results obtained using this equation are consistent with experimental observations. Finally, optimal factor settings for minimum wear rate are determined using genetic algorithm.

Erosion wear in heat treated tool steels used in core boxes at automotive foundries

Sand cores are extensively used on automotives foundries, if a core box is used as core making pattern; erosive wear damage is caused by the silica sand blown. Multiple sand impacts affect the dimensional profile of the core box when the sand is blown causing core rejection. The objective of the present study is to determine the erosion wear rate and the erosive wear mechanism on two tool steel grades, AISI H13 and AISI P20. Both the steels were heat treated, quenched and tempered, to obtain certain hardness values similar to those are used in core boxes. In addition studies on annealed AISI H13 and carburized AISI P20 were proposed to get broader hardness values. The tests were developed in a sand blast type machine specially designed to impact the blown sand in six different angles between 20° and 90°, the blown pressure was same as that utilized in core making machines. The erosion rate is defined as loss of weight caused by the mass of the erosive particles impacted. When the steels are under maximum hardness condition the higher erosion rate is found for angles greater than 60°. The erosive mechanism was characterized using optical and electronic microscopy techniques on the worn layer. When, the hardness is maximum the loss of weight is due to shear adiabatic bands where as in the annealed samples these bands were not observed.

Wear performance of sandwich structured WC–Co–Cr thermally sprayed coatings using different intermediate layers

Cermet based WC–Co–Cr thermally sprayed coatings are known for their good wear and corrosion performance. Different intermediate layers with various deposition processes were performed between cermet WC–Co–Cr coatings to form a sandwich structure to enhance adhesion and to damp particle impacts during erosion. As the outer cermet layer exhibits high hardness against abrasion whereas the intermediate layer is ductile to damp the shock due to particle impact in erosion, sandwich coatings might have potential improvement in life time of coated tools used in mining, drilling, cutting and grinding. Adhesion tests were performed and the tribological behavior of cermet coating and sandwich structured materials was mainly investigated with dry erosion and high pressure slurry jet erosion tests with 30° and 90° impinging angles to study wear mechanism and particle impact at interfaces between coatings. In this work, the adhesive strength of different coatings was measured for each combination. Cermet coating, combinations of Ni–Cr 80–20 and Ni-plating showed high strength value. In spite of the low erosive wear rate Ni–Cr 80–20, the metallographic examination revealed many cracks within this coating due to the particle erosion at high pressures that has been found to drive microcracks through the interfaces between splats leading to flaking of the sprayed coatings. The electrochemically deposited interlayer showed better tribological performance under metallographic observation, because of its homogeneous microstructure, since the electrochemical deposition does not provide splat formation. Consequently, the absence of discrete interfaces limits crack initiation within the coating and at the interface. However, the microstructure of the interlayer is known to be related to coating deposition process such as microsplats and oxide formation in spraying process. Therefore, the influence of microstructure on wear mechanism was investigated.

<sub></sub>Preparation and Wet Erosive Wear Characteristics of Porous Al<sub>2</sub>O<sub>3</sub> Ceramics

Porous Al2O3 ceramics were produced by a dry pressing technique and their characteristics were assessed. In terms of their microstructure the results showed that the open porosity varies with the type of pore-making agents. The open porosity is increased but fracture strength is decreased with an increase in the amount of pore-making agent. The fracture strength of Al2O3 ceramic matrix is increased by adding 5-15wt% ZrO2 particles (ZTA). In terms of their wet erosive wear characteristics the results from liquid-solid impinging jet tests can be used to determine the weak aspects of their microstructure. From examination of worn surfaces it is apparent that grain pull-out is the dominant mechanism of erosive wear. For the porous ceramics, wet erosive wear rate depends on strength, porosity and pore size. For porous Al2O3 ceramics having the same level of porosity, the larger the biggest pore size the higher the erosive wear rate. ZTA composite ceramic has a higher erosive wear resistance than that of Al2O3 ceramic with an equivalent level of porosity primarily due to its higher strength.

Surface fatigue processes at impact wear of powder materials

The problem of the fatigue strength of wear resistant materials is significant both from the theory and practical point of view. In abrasive wear two different mechanisms of material removal occur either separately or simultaneously. At abrasion and low-angle abrasive erosion, microcutting is dominating and the main criterion for materials selection is hardness. At abrasive impact wear and high angle abrasive erosion by irreversible deformation, direct fracture and low-cycle fatigue mechanism are dominating and materials fracture toughness is important. The aim of this work is to determine and compare fatigue behaviour at abrasive erosion and abrasive impact wear as well to study surface fatigue of the high-tech powder materials—PM/HIPed tool steels and conventional wear resistant steels. An attempt to find correlation between abrasive erosion and abrasive impact wear rates with materials surface fatigue resistance was made.

Corrosive-Erosive Wear Studies of Al6061/Albite Composites

This investigation analyses the influence of dispersed alumina particles on the wear behaviour of the Al/albite composites in a corrosive environment. The composites were prepared by modified pressure die-casting technique. The corrosiveerosive wear experiments were carried out on a proprietary corrosion-erosion wear tester to study the wear characteristics of the composites. The slurry was made up of water and alumina(size: 90-150μm, proportion: 0 to 30 wt %) , while H2SO4 (0.01N, 0.1 N and 1 N) was added to create the corrosive conditions. Experiments were arranged to test the relationships among the corrosive-erosive wear rate, concentrations of H2SO4 and alumina in the slurry, weight percent of albite in the composite, erosion speed and distance. Wear rate varies marginally at low speeds but sharply increases at higher speeds. The corrosive wear rate logarithmically increased with the increasing concentration of the corrosive medium. The effect of abrasive particles and corrosion medium on the wear behaviour of the composite is explained experimentally.

Erosion Wear Characteristics of Si<sub>3</sub>N<sub>4</sub> Fabricated from Low-Cost Powders

High producing cost is one of the important reasons that silicon nitride ceramics can’t be widely used today. In this paper, one kind of commercial low-cost silicon nitride powder was used as raw material. High density samples were obtained through pressureless sintering with alumina, yttria and magnesia as sintering aids. The Si3N4 material was tested and the erosion wear rate was measured. It was found that the low cost and dense Si3N4 ceramics exhibited a better erosion wear resistance than the hot-press ceramics produced with the UBE Si3N4 powder and much better then the Cr-26 cast iron. The worn surface was observed with the SEM and the erosion wear mechanisms were analyzed.

海水すべり軸受材のトライボ特性―揺動すべり試験と回転すべり試験の比較

This study aimed at finding out a suitable material for sliding bearings used in seawater. We carried out two types of wear experiments: oscillatory sliding type and ball-on-disc type; using phenolic resin, PTFE resin, polyamide (PA) resin and Pb-Cu sintered alloy sliding against SUS304. As a result, PA resin shows high wear resistance and low friction, whereas phenolic and PTFE resin indicates different tribocharacteristics depending on the type of wear experiment. Pb-Cu sintered alloy is an unsuitable material for bearings in seawater because of its high corrosive wear rate and high fiction.

Erosion Wear Behavior of TiCN–Ni Cermets Containing Secondary Carbides (WC/NbC/TaC)

The present communication reports the results of a first set of erosion wear experiments, conducted on TiCN–20 wt% Ni cermets containing different secondary carbides (WC, NbC, and TaC). The cermets are eroded by SiC particles (66 μm size) with a constant mass flow rate (2.33 g/s) at different angles of impingement (30°, 60°, 90°) on an in‐house fabricated erosion wear tester. An important experimental observation is that the investigated cermets exhibit behavior similar to ceramics, as evident from the systematic increase in erosion wear rate with impact angles. Among all investigated cermets, WC‐added TiCN–20 wt% Ni cermets exhibit superior erosion wear resistance. SEM investigations of eroded surfaces (normal incidence) reveal grain pullout with intergranular fracture as the dominant material removal process.

Effects of wheat starch on erosive wear of E-glass fibre reinforced epoxy resin composite materials

Erosive wear tests were carried out to study the effects of particle, impingement angle and particle velocity on the solid particle erosion behaviour of E-glass fibre reinforced epoxy resin (GFRP) composites. The erosive wear of wheat flour powder filled composites is evaluated at different impingement angles from 30° to 90° and at three different velocities of 24, 35 and 52 m s −1. The erodent used is silica sand with the size range 150–250 μm of irregular shapes. The result shows erosive wear rates of GFRP composite with 2 g wheat flour, as filler is the lowest. This restricts fiber-matrix debonding. Pure glass epoxy without any filler shows the highest erosion rate due to weak bonding strength. The morphologies of eroded surface were examined by the scanning electron microscope.

Study of corrosive–erosive wear behaviour of Al6061/albite composites

This investigation analyses the influence of dispersed alumina particles on the wear behaviour of the Al/albite composites in a corrosive environment. The composites were prepared by modified pressure die-casting technique. The corrosive–erosive wear experiments were carried out on a proprietary corrosion–erosion wear tester to study the wear characteristics of the composites. The slurry was made up of water and alumina (size: 90–150 μm, proportion: 0–30 wt.%), while H 2SO 4 (0.01, 0.1 and 1N) was added to create the corrosive conditions. Experiments were arranged to test the relationships among the corrosive–erosive wear rate, concentrations of H 2SO 4 and alumina in the slurry, weight percent of albite in the composite, erosion speed and distance. Wear rate varies marginally at low speeds but sharply increases at higher speeds. The corrosive wear rate logarithmically increased with the increasing concentration of the corrosive medium. The effect of abrasive particles and corrosion medium on the wear behaviour of the composite is explained experimentally, theoretically and using scanning electron microscopy.