Slurry Speed Research Articles

Experimental Investigations on Erosion-Corrosion Characteristics of HVOF-Sprayed WC-10% Ni Coatings Deposited on Aluminum Alloy

The current work investigates the erosion-corrosion behaviour of thermally sprayed tungsten carbide-10% nickel (WC-10% Ni) coatings placed on the AA6061 aluminum alloy. The AA6061 aluminum alloy was coated with tungsten carbide –10% nickel coatings utilising a high-velocityoxy-fuel (HVOF) spray method. The microstructure and hardness of thermally sprayed coatings were examined using a scanning electron microscope (SEM) and a Vickers hardness tester. The slurry erosion-corrosion wear tests were carried out by varying the parameters of the slurry erosion process, such as testing time, slurry content, slurry speed, and impinging particle size, on the erosion testing equipment. The data demonstrated that when slurry concentration, slurry speed, and impinging particle size increased, so did the slurry erosion-corrosion wear loss. The wear processes of uncoated and thermally sprayed tungsten carbide –10% nickel have been examined using SEM and a 3-D confocal microscope.

Effect of groove depth on the slurry erosion of V-shaped grooved surfaces

The fabrication of microstructures on surfaces is an innovative approach to relieve slurry erosion. Understanding the effect of the dimensions of the surface microstructure on slurry erosion can inspire new surface treatments, not only for small flow-handling parts but also for large water conservancy facilities. Our previous work has studied the effect of the micro structure's shape on slurry erosion. As an extension, the dimension was investigated based on the selected groove structure. Five V-shaped grooved surface microstructures (V1–V5) with different depths (1–5 mm, respectively) were designed. The effect of groove depth on erosion was studied by scanning electron microscopy observation and mass loss, roughness, and residual stress measurements at a slurry speed of 8.29 m s-1, particle size of 75–150 mesh, and sand concentration of 3 wt%. The results showed that the best erosion resistance occurred at a critical depth of 3 mm. This was partially due to the low-velocity component in the flow direction and the upward velocity component perpendicular to the flow direction. This velocity distribution inhibited the impingement erosion of the particles inside the groove and simultaneously slowed the incoming particles into the groove. The groove surfaces underwent the most severe erosion, while the top surfaces experienced less erosion, which was relieved by multiple vortices induced by the grooves. The erosion rates of V3, V4, and V5 were lower than those of V1 and V2. The erosion mechanisms are summarized to guide the design optimization of surface microstructures.

An assessment of erosive wear of hydro-turbine steel using statistical modelling and optimisation

The current study pertains to the influence of chosen process parameters on erosive wear of F6NM stainless steel. Response surface methodology was used to plan experiments. Response surface method with face centred composite design has been adopted to develop a regression model. Development of erosive wear model was based on five factors, which included sediment concentration (A), particle size (B), angle of impact (C), test duration (D) and rotational speed of slurry (E). A mathematical model was developed to predict the deterioration through wear on F6NM stainless steel and the appropriateness of the model was certified using analysis of variance. A robust correlation is attained between the model predicted and experimentally obtained values for weight loss and the percentage of error is 12%. On the basis of mathematical model, single objective optimisation of parameters has been performed with genetic algorithm (GA) technique and this method yields reduction of 34.78% for material wear.

Comparative study on effects of slurry erosive parameters on plasma sprayed flyash-Al<SUB align="right">2O<SUB align="right">3 and flyash-SiC composite coatings on Al6061 alloy

In this present investigation, an attempt has been made to study the potential use of plasma sprayed flyash-Al2O3 and flyash-SiC novel composite coatings on Al6061 alloys to mitigate slurry erosive wear. In this Taguchi's L27 statistical approach, the influence of various process parameters like, slurry concentration, slurry speed, impinging particle size and testing specimen on the slurry erosive wear in slurry with 3.5% NaCl solution were evaluated and analysed. The results obtained indicate that testing specimen and slurry concentration were greatly influencing on slurry erosive wear than slurry speed and particle size. Under all the test conditions studied, flyash-Al2O3 coatings on Al6061 alloy exhibited higher resistance to slurry erosive wear when compared with flyash-SiC coated and uncoated Al6061. Mathematical models were developed by means of regressive analysis to predict the slurry erosive wear of developed composite coatings. This will enable the predictive design of important products with the minimum of wastage and maximum utilisation of sustainable materials using environmentally friendly processes.

Comparative study on effects of slurry erosive parameters on plasma sprayed flyash-Al<SUB align="right">2O<SUB align="right">3 and flyash-SiC composite coatings on Al6061 alloy

In this present investigation, an attempt has been made to study the potential use of plasma sprayed flyash-Al2O3 and flyash-SiC novel composite coatings on Al6061 alloys to mitigate slurry erosive wear. In this Taguchi's L27 statistical approach, the influence of various process parameters like, slurry concentration, slurry speed, impinging particle size and testing specimen on the slurry erosive wear in slurry with 3.5% NaCl solution were evaluated and analysed. The results obtained indicate that testing specimen and slurry concentration were greatly influencing on slurry erosive wear than slurry speed and particle size. Under all the test conditions studied, flyash-Al2O3 coatings on Al6061 alloy exhibited higher resistance to slurry erosive wear when compared with flyash-SiC coated and uncoated Al6061. Mathematical models were developed by means of regressive analysis to predict the slurry erosive wear of developed composite coatings. This will enable the predictive design of important products with the minimum of wastage and maximum utilisation of sustainable materials using environmentally friendly processes.

Studies on Enhancement of Silt Erosion Resistance of 13/4 Martensitic Stainless Steel by Low-Temperature Salt Bath Nitriding

Low-temperature salt bath nitriding of heat treated and tempered 13/4 Martensitic stainless steel (13/4HTT) was carried at 450 °C (N450) and 500 °C (N500) for 10 h each. The nitrided samples were characterized by using x-ray diffractometer, field emission scanning electron microscope and optical microscope. The nanohardness and elastic modulus of the cross section of nitrided specimen were measured by nanoindentation test using Hysitron TI950 triboindenter. The nitrided 13/4HTT (N450 and N500) and 13/4HTT specimens were subjected to slurry erosion test in a slurry pot tester. The test was conducted for 48 h, and weight loss was measured after every 6 h. The relative speed of slurry with respect to specimen was 4.55 m/s. It was found that the weight loss due to erosion of the N450 is 83% less than that of 13/4HTT and that of N500 was 92% more than that of 13/4HTT. The erosion mechanism is correlated to the phases present in the specimens. The improvement in the slurry erosion resistance of N450 is due to presence of expanded martensite ( $$\alpha_{N}$$ -Fe). Increasing the temperature of nitriding to 500 °C led to the decrease in the slurry erosion resistance of N500 due to the formation of brittle CrN phase.

Slurry erosive wear behaviour of plasma-sprayed flyash–Al2O3 coatings

ABSTRACTThe present investigation focuses on the study of erosive slurry wear behaviour of plasma-sprayed flyash–Al2O3 composite coatings on the substrate of Al6061 alloy in slurry with 3.5% NaCl solution. The influence of various process parameters, such as different slurry concentration (10–30%), varying rotational speed (500–1500 rev min−1) and varied impinging particle sizes (210–425 µm), was compared by conventional weight loss method and Taguchi’s L27 experimental design method. It was observed that the composite coatings on Al6061 alloy showed a highest resistance to erosion. The significance of the parameters was determined by using analysis of variance technique and it was found that the factors slurry concentration and slurry speed had great influence on erosive slurry wear of substrate with and without plasma spray coatings. Regression analysis was used to develop mathematical model to predict the slurry erosive wear. Predicted values are in good agreement with experimental values.

Fuzzy prediction of slurry erosive behavior of cobalt based clad developed through microwave energy

The stainless steel AISI-420 widely used in the manufacture of brake discs, turbine blades, piston submerged in water pumps, injection molds.etc. The present work deals with slurry erosive wear studies of cobalt based clads developed through microwave energy in a domestic microwave oven equipped with 900 W power at 2.45 GHz .The developed clads were subjected to microstructure and sand slurry erosive wear studies were carried out. Taguchi orthogonal array L9 was used to gauge the factors affecting the wear significantly. The influence of various factors such as speed, particle size and impingement angle on wear behavior was evaluated by means S/N ratio. This study reveals the slurry speed had significantly influenced the mass loss of the developed surfaces. The most popular and highly reliable analytical technique Fuzzy logic model has been successfully used to predict the slurry erosive wear behavior. The predicted values have been compared with the experimental data. The obtained average percentage error between experimental and fuzzy logic values are 13.80%.

Taguchi analysis on erosive wear behavior of cobalt based microwave cladding on stainless steel AISI-420

Abstract The strength, hardness, wear and corrosion resistance are the most important mechanical properties of the tribological components. Martensitic stainless steel plays very important role to represent these characteristics. The AISI-420 stainless steel widely used to manufacture the hydraulic and gas turbine components. The present work deals with microstructure and slurry erosive wear studies of cobalt based clad developed through microwave energy at a frequency of 2.45 GHz. The scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis result reveals the presence of cobalt and chromium rich solid solution in the intercellular substances. The Taguchi orthogonal array was used to gauge the factors affecting the wear significantly. The influence of various factors such as speed, particle size and impingement angle on wear behavior was evaluated by Means and ANOVA (analysis of variance). It was observed that the slurry speed significantly influenced the more mass loss on unclad substrate. The wear mechanism of the worn surface was studied through a scanning electronic microscope. It shows the mixed mode of erosion in the form of microcutting, ploughing, and fractures appeared are major wear mechanisms.

Microstructure and experimental design analysis of nickel based clad developed through microwave energy

Summary In the present investigation microwave processing method was explored for the enhancement of surface properties of austenitic stainless steel (SS-304). The nickel based clads were developed through microwave energy. Taguchi's L9 orthogonal array was successfully adapted to study the slurry erosive wear rate. The obtained result indicated that erosion rate of the developed clad varied between 0.03363 g to 0.03570 g as an increase in slurry parameters like slurry velocity and impingement angle respectively. It is confirmed by the response table for means of DOE that the wear rate of the developed clad was more influenced by the rotational slurry speed and impingement angle; finally the possible mechanisms of the worn surface of the tested samples were observed through SEM.

Examination of the Material Removal Mechanisms During the Abrasive Jet Finishing of 45 Steel

The abrasive jet finishing is a kind of compound machining process that combines grinding with loose particles finishing: a slurry of an abrasive and a liquid solvent is injected into the grinding zone between the grinding wheel and work surface, under grinding wheel stops cut-in feed conditions, after workpiece grinding has been done. The abrasive particles are driven and energized by the rotating grinding wheel, liquid hydrodynamic pressure, and increased slurry speed between the grinding wheel and work surface to achieve micro-removal finishing. In this paper, the material removal mechanisms of abrasive jet finishing with grinding wheel as restraint was investigated, based on the size ratio of characteristic particle size to film thickness between grinding wheel and workpiece. The single abrasive movement characteristic was studied under two-body lapping and three-body polishing mode. The critical condition for transformation from two-body lapping to three-body polishing was analyzed. Experiments were conducted for theoretical modes verification. It was found that the theoretical analysis is accordant with experimental results.

Slurry erosive wear behavior of Ni–P coated Si3N4 reinforced Al6061 composites

Ni–P coated Si3N4 reinforced Al6061 composites were fabricated by liquid metallurgy route. Percentage of reinforcement was varied from 4wt% to 10wt% in steps of 2. The developed composites were subjected to microstructure and sand slurry erosive wear studies. The influence of experimental parameters such as slurry concentration, rotational speed of slurry, size of impinging particles and the test duration on slurry erosive wear behavior of developed composites have been studied. Results reveals that, Al6061–Si3N4 composites exhibited improved wear resistance when compared with the matrix alloy under identical test conditions. With increase in slurry concentration, rotational speed of slurry, test duration, size of impinging particles, the slurry erosive wear rates of both matrix alloy and developed composites increases. However, under all the tests conditions studied, the developed composites possess higher wear resistance when compared with that of matrix alloy. Energy dispersive spectroscopy (EDS), X-ray diffraction analysis (XRD) and X-ray photoelectron spectroscopy (XPS) techniques were used to identify the oxides/passive layer formed on the worn surfaces. Scanning Electron Microscopy (SEM) examinations were also carried out on worn surfaces to observe the possible mechanisms of material removal in the matrix alloy and developed composites.

Power Spectral Density and Cross Correlation Function Analysis of Finished Surface by Abrasive Jet with Grinding Wheel as Restraint

The abrasive jet finishing process with wheel as restraint is a kind of compound precision finishing process that combined grinding with abrasive jet machining, in which inject slurry of abrasive and liquid solvent to grinding zone between grinding wheel and work surface under no radial feed condition when workpiece grinding were accomplished. The abrasive particles are driven and energized by the rotating grinding wheel and liquid hydrodynamic pressure and increased slurry speed between grinding wheel and work surface to achieve micro removal finishing.In the paper,the finished surface morphology was studied using Scanning Electron Microscope (SEM) and microscope and microcosmic geometry parameters were measured with TALYSURF5 instrument respectively. According to the metrical results, the surface topographical characteristics were evaluated with correlation function and PSD (Power Spectral Density) of random process about machined surface before and after finishing. The results show that longitudinal geometry parameter values of finishing machining surface were diminished comparing with ground surface,and the mean ripple distance was decreased and, ripple and peak density were increased. Furthermore, the finished surface has little comparability compared to grinding machining surface.The isotropy surface and uniformity veins at parallel and perpendicular machining direction were attained by abrasive jet precision finishing with grinding wheel as restraint and the surface quality is improved obviously.

Power Spectral Density Analysis Finished Surface by Abrasive Jet with Grinding Wheel as Restraint

The abrasive jet finishing process with wheel as restraint is a kind of compound precision finishing process that combined grinding with abrasive jet precision machining, in which inject slurry of abrasive and liquid solvent to grinding zone between grinding wheel and work surface under no depth of cut feed condition when workpiece grinding were accomplished. The abrasive particles are driven and energized by the rotating grinding wheel and liquid hydrodynamic pressure and increased slurry speed between grinding wheel and work surface to achieve micro removal machining. The micro removal machining with grinding wheel as restraint, not only to attain higher surface form accuracy but also to can efficiently acquire defect-free finishing surface with Ra0.15~1.6$m and finally achieve high efficiency, high precision and low roughness values, furthermore, integrating grinding process and abrasive jet finishing into one features. In the paper, surface topography finished by abrasive jet with grinding wheel as restraint was analyzed and evaluated with power spectral density function. Experiments were performed with plane grinder M7120 and workpiece material 45 steel. The machined surface morphology was studied using Scanning Electron Microscope (SEM) and the microscope and microcosmic geometry parameters were measured with TALYSURF5 instrument. The experimental results show that microcosmic geometry parameter values were diminished comparing with ground surface. Furthermore, the mean ripple peak distancing was decreased and, ripple and peak density were increased. The results indicate that surface qualities by machined with abrasive jet precision finishing were improved obviously.

Study on Surface Topography and Tribological Characteristics Finished by Abrasive Jet with Grinding Wheel as Restraint

The abrasive jet finishing process with wheel as restraint is a kind of compound precision finishing process that combined grinding with abrasive jet machining, in which inject slurry of abrasive and liquid solvent to grinding zone between grinding wheel and work surface under no radial feed condition when workpiece grinding were accomplished. The abrasive particles are driven and energized by the rotating grinding wheel and liquid hydrodynamic pressure and increased slurry speed between grinding wheel and work surface to achieve micro removal machining. The micro removal machining with grinding wheel as restraint, not only to attain higher surface form accuracy but also to can acquire efficiently defect-free finishing surface with Ra0.15～ 1.6μm and finally achieve high efficiency, high precision and low roughness values, furthermore, integrating grinding process and abrasive jet process into one features. In the paper, surface topography and tribological characteristics finished by abrasive jet with grinding wheel as restraint were analyzed. Experiments were performed with plane grinder M7120 and workpiece material Q235A. The machined surface morphology was studied using SEM and the microscope and microcosmic geometry parameters were measured with TALSURF5 instrument. The experimental results show that microcosmic geometry parameter values were diminished comparing with ground surface. The tribological characteristics of finished surface were also investigated with pin on disk wear tester of MG-2000. The experimental results show that the friction coefficient and wear amounts of finishing machining surface were obviously decreased comparing with ground surface. As a result, life and precision consistency of finished workpiece were improved.

Ａｌ‐Ｓｉ二元系鋳造合金のスラリー・エロージョン挙動

The purpose of this study is to clarify slurry-erosion mechanism of silicon particle reinforced aluminum alloy base in-situ composites. Using a series of specimens (pure Al, hypoeutectic of Al-7mass%Si, fully eutectic of Al-12.6mass%Si and hypereutectic of Al-20mass%Si, Al-30mass%Si and Al-40mass%Si), slurry erosion test was conducted for 1.26×105s (35h) at 293K under a constant slurry speed of 8.55m/s. Sand volume fraction of the slurry was changed from 5 to 40vol. %. After the slurry erosion test, amount of weight loss in the specimens was measured to clarify the slurry erosion behavior. The results obtained are as follows. (1) The amount of weight loss depended on strength of the specimens in whole range of sand concentration in the slurry for pure Al and hypoeutectic specimens. (2) And also, the amount of weight loss depend on the sand concentration in slurry and/or the Si concentration in the matrix of the alloy for fully eutectic and hypereutectic specimens. The hypoeutectic specimen showed high slurry-erosion resistance for lower sand volume fraction in the slurry, though the hypereutectic specimen for higher sand volume fraction in the slurry. (3) Therefore, it is important to understand that the slurry erosion behavior depends on a combination of the microstructure of materials and the environmental condition such as sand concentration in the slurry.

Sand Erosion Behavior of Cast Aluminum Alloys

The present paper primarily concerns itself with the use of aluminum alloys for marine applications. The objective of this research is to consider the effects of Mg concentration, slurry speed, sand grain size, sand-to-water ratio and temperature on the sand erosion resistance of five typical types of aluminum alloys. Quantitative relationships for these were also derived.Cylindrically-shaped test specimens were attached to a rotating disc immersed in a slurry. Erosion rate was based on the amount of weight loss. Mg concentration varied depending on the alloy used. Slurry speed varied with the rotation of the disc. Three types of sand were examined and their respective grain sizes determined. Sand-to-water ratio was varied from 0-40% and tests were conducted using temperatures of 293K and 280K.From the given conditions, the following conclusions were derived. In Al-Mg type of alloys, the sand erosion resistance increases when the magnesium content increases. The factors affecting erosion rate (Wk) mainly consist of slurry speed (V), sand grain size (F) and sand volume percentage (p). Also, the relationship may be shown in the following formula:Wk=K·p1/2(Vn/Fm)

高クロム白鋳鉄のサンド・エロージョン速度のスラリー速度依存性

The relation between eroding rate (Wk) and slurry speed (V) was given by Wk=KVn (K: constant) on sand-erosion of 15%Cr and 15%Cr-3%Ni eutectic white cast irons. The experimental expression of the eroding rate, which was obtained through the slurry temperature and slurry speed dependences of the sand-erosion characteristics, was in good agreement with the measured eroding rates. The erosion behavior and the eroded sureface structure suggested the change of the eroding mechanism at low and high-slurry speed ranges. The change of the eroding behavior was assumed to be related to the yield stress of the specimens. However, the applied stress due to particle collision at the change of the eroding behavior was calculated to be much higher than the yield stress. This difference was speculated to be due to the composite microstructure of eutectic carbide and the matrix in the high chromium white cast irons.

Erosion in seawater sand slurries

This article describes the influence of the experimental parameters, angle of attack, slurry speed, sand particle size and sand concentration on the slurry erosion in sand-water mixtures of two reference materials, steel C22 and natural rubber. In addition, the results of comparative erosion testing of 25 commercially available construction materials for application in sand slurry transportation systems are given in the form of a bar chart, in which the wear resistance of each material is compared with that of the reference material C22.