Slurry Pot Tester Research Articles

Experimental investigation of wear behaviour of WC-10Co-4Cr-coated SS304 on slurry pot tester

Purpose The paper aims to investigate the effects of slurry erosion on hydro turbine components, focusing on the experimental analysis of SS-304 using sand as the erodent material. The study was conducted on a tester under varying parameters to assess the material’s erosion behavior. In this work, the experimental investigation of SS-304 with sand was done with sand as the erodent material on a tester with various parameters. Further, the materials were made more resistant to wear by a WC-10Co-4Cr coating, done by the high-velocity oxygen fuel method. The mass loss of the specimens with and without coating was calculated. SEM was carried out on the specimens. The specimens with coating showed greater erosion resistance than the base material; however, wear mechanisms such as craters, lip formation, pores, etc. were discovered on the specimens. Design/methodology/approach The wear tests were carried out on the specimens with parameters of rotating speeds of 1,000, 1,150, 1,300 and 1,450 rpm; time duration 80, 130 and 180 min with sand concentrations of 30% and 50% in water. The base material was coated with WC-10Co-4Cr by the HVOF method of thermal spray. Findings In the results, it was observed that the wear resistance of the coated specimen increased significantly as compared to the uncoated material. Concentration proved to be the major factor influencing the wear erosion followed by rotational speed and time period. Various surface defects such as ploughing, crater formation, lip formation and micro-cutting were also found. Originality/value Slurry concentration was found to be the more dominant factor in increasing the wear of the specimens. The tests proved that the coating proved to be highly wear-resistant as compared to the uncoated base material and increased the wear resistance up to 3 times.

SURFACE EROSION PERFORMANCE OF YTTRIUM OXIDE BLENDED WC-12CO THERMALLY SPRAYED COATING FOR MILD STEEL

This study is conducted to examine the tribological performance of WC-12Co coating and WC-12Co mixed with yttrium oxide coating applied on mild steel. Mild steel machinery is usually used for hydropower generation but the sediments present along with the river water cause wear on the machinery surface. DUCOM slurry pot tester setup was used for the experiments. This study was based on the coatings of WC-12Co as well as the mixing of yttrium oxide with WC-12Co powder in various proportions ranging from 1–3% by weight on mild steel. The high-velocity oxygen fuel thermal spray coating process was used to deposit a microlayer coating on the mild steel. It is observed that the microhardness of the coatings increases with the addition of yttrium oxide. The experiments were carried out varying the concentration, rotational speed, and test duration in the range of 10–40% by weight, 750–1500[Formula: see text]rev/min, and 30–120[Formula: see text]min duration, respectively. It is observed that the WC-12Co+2%Y2O3 coating has a higher erosion resistance.

Surface Damage Analysis on the Application of Abrasion and Slurry Erosion in Targeted Steels Using an Erosion Test Rig

The research focuses on slurry abrasion and erosion of martensitic steels used in the mining and agricultural industries. A traditionally constructed slurry pot tester with corundum abrasives in slurry form was used for wear characterisation. Wear testing was performed on each specimen for 180 h. Every 20 h, pauses were taken to characterise the specimen size, weight, hardness, and surface roughness. The worn zone’s damage progression was studied using optical microscopy. As the test period rose, the mass loss due to the wear, which was governed by the impact angle of the slurry flow, followed a linear pattern. The impact of specimen orientation on the wear rate was more pronounced than that of abrasive flow velocity. High-speed video recordings highlighted the varied contact conditions that caused the wear mechanism to shift from abrasion to slurry erosion. Slurry abrasion was seen at the bottom of the specimen as a result of pure sliding conditions, while pitting was observed at the top of the specimen as a result of fatigue from particle impact. Studies of 3D surfaces demonstrated a decrease in wear rate while transitioning from the abraded zone, which witnessed polishing and minor hardness, to the pitting zone. The wear performance of the materials was rated, with tempered martensitic steel coming out on top.

The effect of microstructure and mechanical properties on the slurry erosion behavior of carbide-free bainitic and martensitic steel

The effect of microstructure and mechanical properties on the slurry erosion behavior of carbide-free bainitic (CFB) steel, austempered at 350, 400 and 450 °C and quenched and tempered martensitic (QT) steel, tempered at 300, 400 and 500 °C has been investigated using slurry pot tester and silica sand erodent particles. The samples were tested for 15 h with a rotating speed of 1000 rpm. The result shows that the QT steel has better erosion resistance than the CFB steel. The retained austenite (RA) phase fraction (17.75%) in 350 °C austempered sample, which provides erosion resistance by transformation-induced plasticity effect, is sufficient for outstanding erosion performance among the CFB steels. However, this RA phase fraction in CFB steel is inadequate to provide better erosion resistance than the QT steel. Among all the samples tested, the sample which is tempered at 300 °C shows the best slurry erosion resistance. The analysis of the results suggests that the hardness and transformation-induced plasticity associated with RA phase fraction, are the deciding factors for erosion resistance in QT and CFB steel, respectively. The material removal mechanism in the CFB steel is the crater formation leading to fatigue failure of lips and coalescence of micro-craters, whereas in QT steel it is only fatigue failure of lips.

CFD Simulation and Experimental Results Validation of Slurry Erosion Wear using Slurry Pot Test Rig

Erosion wear is a severe issue in different industrial applications results in economic costs and operational failure. In most of the industry pipelines are used to handle the slurry during industrial process, the slurry handling pipeline is failure due to erosion wear. The slurry pot test rig is developed and fabricated for investigating the erosion wear rate of different material and solid particles used in the slurry pipeline with various working conditions. The various influencing parameters such as solid particle flow velocity, impact angle, solid particle size, and concentration are responsible for the rate of material loss and erosion wear mechanisms. The present study is based on experimental work and its validation of results of slurry erosion wear for slurry handling pipeline using slurry pot test rig and CFD simulation. For experimentation, mild steel is used as pipeline material and coal bottom ash is used as solid particles for simulating slurry handling pipeline use in a thermal power plant. The experimentation is performed on the slurry pot test rig. The computational fluid dynamics (CFD) tool is used to predict and simulate the experimental results of the slurry pot test rig. The simulation results compared with experimental results and check the percentage of errors with both the results. The simulation results show a similar kind of trend for erosion wear behavior of mild steel as per the experimental results. Simulation results show the average error up to ± 21% variation with the experimental result. The simulation results give the position of erosion wear over the sample surface.
 HIGHLIGHTS
 
 Erosion wear is the major problem in slurry handling industries (thermal power plant, chemical industries, hyro-power plants, coal minis) and components (Pipelines, Centrifugal pumps, flow control valve, turbines etc.)
 Experimental worked conducted to find the erosion wear rate and material removal mechanism of pipeline material (MS) with simulating thermal power plant conditions. Similarly software simulation analysis performed for same conditions
 The experimental results give the exact value of erosion wear rate but it does not show the position of maximum wear over the sample surface. Therefore, the experimental results are used for finding the erosion wear rate i.e. value of the sample and simulation results are used for finding the position of maximum erosion wear over the target sample
 
 GRAPHICAL ABSTRACT

Neural Network Prediction of Slurry Erosion Wear of Ni-WC Coated Stainless Steel 420

In the present study, Erosion wear of stainless steel 420 was predicted using an artificial neural network (ANN). Stainless steel 420 is used for making slurry transportation components, such as pump impellers and casings. The erosion wear performance was analyzed by using a slurry pot tester at the rotational speed of 600–1500 rpm with a time duration of 80–200 min. Fly ash was used as an erodent medium, and the solid concentration varied from 20 to 50%. The particle size of erodent selected for the erosion tests was <53 µm, 53–106 µm, 106–150 µm, 150–250 µm. A standard artificial neural network (ANN) for the prediction of erosion wear was designed using the MATLAB program. Erosion wear results obtained from experiments showed a good agreement with the ANN results. This technique helps in saving time and resources for a large number of experimental trials and successfully predicts the erosion wear rate of the coatings both within and beyond the experimental domain.

Wear law of Q345 steel under the abrasion–corrosion synergistic effect of cemented paste backfill

Excessive pipe wear affects the continuity and safety of the delivery of cemented paste backfill (CPB). However, the dominant factors affecting the wear of CPB transportation pipelines are not well understood. The goal of this study is to determine the wear law of the Q345 steel pipeline under the abrasion–corrosion synergistic effect of CPB at varying mass fractions (76–82%), flow velocities (1–2.5 m/s), and rheological parameters. A mini cathodic protection system was installed in the slurry pot tester to simultaneously acquire the total wear and pure abrasion, while pure corrosion was obtained via immersion testing. The results indicate that the total wear and pure abrasion exhibit a power-law increase according to flow velocity and grow exponentially as the CPB mass fraction increases. CPB with increasing yield stress and plastic viscosity leads to an exponential growth in the total wear and pure abrasion. However, a higher solid fraction not exceeding a certain critical value effectively alleviates pipe wear and resistance. In most cases, the synergistic effect of abrasion–corrosion contributed to more than 50% of the total wear. CPB mass fraction and the abrasion-corrosion synergistic effect are the dominant factors affecting the total wear of the CPB-transporting pipeline and should be properly controlled in practice. CPB with a solid fraction ranging between 76 and 78% at a flow velocity of 1.57 m/s and pipelines made of corrosion-resistant materials are recommended for the mine of interest. The findings are conducive to the selection of appropriate pipeline materials and CPB transportation parameters.

Study on Solid Particle Erosion of Pump Materials by Fly Ash Slurry using Taguchi’s Orthogonal Array

Various grades of stainless steel are used to fabricate the pump impeller, casings, and seals used in heavy-duty erosion and corrosion conditions. In the present study, stainless steel (SS316L, SS304, SDSS2507) and grey cast iron used in the fabrication of heavy-duty pump impellers were taken for the analysis of solid particle erosion. Experiments were conducted on the lab-scale slurry pot tester. Fly ash slurry was prepared of different concentrations (wt%). Taguchi’s orthogonal array is used to design the experiments of erosion wear for the variation of rotational speed, solid concentration, time, and particle size. Results showed that SS316L showed superior microhardness and wear behavior against the fly ash slurry followed by SS304, SDSS2507 and Grey cast iron.

Erosion wear analysis of thermally sprayed WC + TiO2 micron layers on SS-404

SS 404 is one essential material because of its anticorrosion and high heat resistance property. Also, the hardness of SS 404 is less than other available steel. Therefore, to resolve the problem of micro-hardness (improve micro-hardness) of SS 404, coating of WC (80%) with Ti O2 (20%) has been applied. A slurry mixture is prepared to analyze the erosion wear resistance against fly ash, which is examined in a slurry pot tester. The slurry of different particle sizes such as 106–150 µm, 150–212 µm, 212–300 µm, and 300-350µmhas been considered during the experiment. The rotation speed of the pot has been set at 600, 850, 1100, and 1350 rpm with a total time period of 90 min. High-Velocity Oxygen Fuel (HVOF) coating is sprayed on the SS 404 as protection material against erosion. From the experiment, it is observed that coated WC with TiO2 performed well against erosion compared to uncoated SS 404.

Comparison of slurry erosion performance of thermally sprayed coatings with the addition of TiO2 feedstock powder

The present study examines the tribological performance of Ni–20%Al2O3 and Ni–20%Cr2O3 composite coatings HVOF (High Velocity Oxy-Fuel) sprayed on pump impeller material i.e., SS-420. Also, 5% amount of TiO2 feedstock powder was mechanically blended to both Ni–Al2O3 and Ni–Cr2O3coatings to analyze the enhancement in erosion wear resistance. The erosion wear performance was analyzed by slurry pot tester at the rotational speed of 750–1500 r.p.m. for the time period of 30–120 min. Fly ash was selected as the slurry material and fly ash concentration varied from 35 to 50% with the particle size domain of < 53 to 250 µm. Mechanical and surface characterization was also carried out to analyze various properties of composite coatings. Results show that 5% addition of TiO2 feedstock powder to Ni–20% Al2O3 and Ni–20%Cr2O3composite coatings has significantly improved the erosion wear resistance of SS-420. From present investigation, it was also found that Ni–15%Cr2O3–5%TiO2 coating has more erosion resistance as compared to Ni–15%Al2O3–5% TiO2 coating.

Slurry erosion behaviour of Ni-Hard under various impact angle and speed

To Study wear analysis of slurry pump with an experimental condition is an economically costly and lengthy process. Therefore, wear study can be done on various laboratory tests such as Slurry pot tester, Coriolis wear tester, Whirling arm wear test device, particle impact jet test. To analyze of erosion wear rate of slurry pump material in different operating conditions is performed on slurry pot tester. In the latest pump the Ni-Hard is widely used material in the slurry transportation. The one of the major application of slurry pump made from Ni-Hard is in Thermal power plant for ash slurry transportation. In this paper an experimental work has been carried out to find the effect of impact angle and particle impact speed at 20% w/w slurry concentration of sand on the wear rate of the Ni-Hard material. From the experimental results it is found that as particle velocity increases erosion wear rate of the material is increases. It was also found that the erosion of the material increases with impact angle till 30° then the erosion of material decreases gradually.

Investigation on the impact of physical properties of the coal-ash slurries on the erosion wear performance of WC coated steel by using Image processing technique

ABSTRACT The various properties of carrier flow (e.g. coal, fly, and bottom-ash slurries) having a major impact in determining the equipment life of various slurry transportation components such as pipelines, pump impellers, bends, etc. Also, in literature, how the size and shape of different erodent affect the various erosion characteristics remain undiscovered. In this study, we propose the use of Scanning Electron Microscopy, Image J software, Energy dispersive spectroscopy, and Ducom slurry pot tester to investigate the effect of particle shape and size, circularity factor, and the impact of various process parameters on the erosion wear of WC-10Co-4Cr-coated SS-410. The experiments were performed by using three different types of erodents such as coal, fly, and bottom ash. The circularity factor, microhardness, and pH value were also measured before the experimentation. Furthermore, Taguchi’s approach was used to optimize the impact of influencing parameters. From experimentation, it was revealed that the acidic coal particles able to generate more erosion wear due to their irregular shape and size. The erosion wear generated by these erodents were in the following order: coal > bottom ash > fly ash. Moreover, the particle sizes having the highest impact on the erosion wear rate of SS-410.

Erosion Wear Behavior of Martensitic Stainless Steel Under the Hydro-Abrasive Condition of Hydropower Plants

The erosive wear of a hydraulic turbine due to suspended solid particles reduces its performance and service life. Martensitic stainless steel CA6NM, used for turbine parts of a hydropower plant, gets eroded heavily every year, particularly in the monsoon period. A high-speed slurry pot tester is employed to investigate the erosion behavior of the material under different operating conditions of practical interest. Scanning electron microscopy (SEM), as well as spark emission spectrometer (SES) and micro-hardness tester measurements, is used to investigate the erosion wear behavior of CA6NM. The impingement velocity is varied from 13 to 32 m/s for the particle size of 90.5–362.5 μm and solid concentration of 500–4000 ppm at different orientation angles ranging from 15° to 90°. The erosion rate for suspension loading is increased with the increase in the impact velocity and particle size but decreased with an increase in suspension concentration. The index value in power-law relationship with erosion rate is found as 2.77 and 3.19 for velocity, and 1.42 and 0.97 for particle size for impingement angle of 30° and 90°, respectively. The micrographic analysis of the eroded sample is performed through a scanning electron microscope (SEM). At shallow impingement angle, the material loss dominantly occurred by micro-cutting and plowing, but at high impact velocity, some spackle of brittle failure is also observed. At large impingement angles, deep craters and crack formation are found responsible for the material loss under the present operating conditions.

Effect of annealing temperature on slurry erosion resistance of ferritic X10CrAlSi18 steel

In the present work, the slurry erosion tests were carried out to investigate the influence of heat treatment on slurry erosion process of ferritic X10CrAlSi18 stainless steel using a slurry pot test rig. X10CrAlSi18 stainless steel was tested in as-received condition and after annealing at three different temperatures: 600 °C, 800 °C and 1000 °C. Degradation of materials due to slurry erosion depends on many factors connected with fluid flow conditions, properties of target material and erodent characteristics. In this case, factors related to the properties of the eroded material such as microstructure, grain size, work hardening, hardness played an important role. The heat treatment decreased hardness of this steel and increased erosion resistance. Microstructure was one of the most important parameters influencing the slurry erosion process of tested materials. X10CrAlSi18 stainless steel after annealing at 600 °C with fine-grained microstructure and the deepest of work hardening layer obtained the best resistance to slurry erosion. Heat treatment contributed to approximately 55%, 23% and 41% decrease in mass loss compared to steel in as-received condition. After slurry erosion tests craters, fracture, ridges and flakes were observed on the eroded surface. Furthermore, to identify the dominant mechanism of erosion, the erosion efficiency parameter was used, η.

Improved slurry erosion resistance of martensitic 13wt.%Cr–4wt.%Ni steel subjected to cyclic heat treatment

To increase the slurry erosion resistance, cyclic heat treatments were performed on 13wt.%Cr-4wt.%Ni steel at 1050 °C for 3, 5, 7, and 9 cycles. Microstructures in as-received and cyclic heat treated (CHTed) conditions were analyzed with the help of optical, SEM, XRD, and TEM. The structure-property correlations were then studied after determining the hardness, microhardness of each phase, and tensile properties. It was observed that the dissolution of M23C6 carbides caused the lath widening which deteriorated the microhardness of the martensite in the CHTed specimens. The increased hardness and tensile strengths were attributed to the reduced delta ferrite and the refined blocks in the CHTed specimens. Slurry erosion behavior of as-received and CHTed specimens was tested by conducting a 24hrs erosion test on slurry pot tester. The CHTed specimen possessed 69.9% higher slurry erosion resistance due to higher hardness and yield strength. During the first 12hrs of erosion, the subsurface hardening due to work hardening reduced the erosion rates significantly while the progressive loss of erosivity of the sand particles reduced the erosion rates in later hours of erosion test. AFM visualized the plastic deformation as a predominant erosion mechanism for all the specimens.

Slurry and dry particle erosion wear properties of WC-10Co4Cr and Cr3C2-25NiCr hardmetal coatings deposited by HVOF and HVAF spray processes

Thermally sprayed hardmetal coatings were produced to provide improved erosion wear compared to conventional cast GX4CrNi13-4 martensitic steel (CA6NM) used in hydro turbine components. Sprayed coatings and reference materials were tested with high-speed slurry pot tester using either fine or coarse quartz as the erosive media. Additional erosion tests were carried out with centrifugal dry erosion tester. Tungsten carbide based coatings provided the highest wear resistance due to the high hardness and even distribution of the fine carbide particles. The cast 13-4 steel samples experienced up to 180 times higher wear rates in fine quartz slurry and up to 36 times higher wear rates in coarse slurry compared to the sprayed coatings.

An erosion and corrosion study on thermally sprayed WC-Co-Cr powder synergized with Mo2C/Y2O3/ZrO2 feedstock powders

The present study is based on erosion wear analysis of WC-Co-Cr powder thermally sprayed on super-duplex stainless steel (SDSS) 2507. A high-velocity oxy-fuel (HVOF) process was used to deposit the WC-Co-Cr thermal spraying powder. A small weight proportion of Mo2C, Y2O3 and ZrO2 feedstock powders was mechanically blended to WC-Co-Cr thermal spraying powder for analyze the improvement in erosion wear. Erosion wear experiments were conducted using a slurry pot tester at a rotational speed of 600–1500 rev/min for time duration of 90–180 min. Sand was used as the erodent medium; the concentration of solid particles was varied from 30% to 60% (by weight). Present study was extended to analyze the mechanical properties of coatings. Results show that the 3% addition of feedstock powders was beneficial to improve the erosion wear resistance of SDSS-2507. The addition of Y2O3 and Mo2C had improved the erosion wear performance of WC-Co-Cr coating. The addition of Y2O3 provided high erosion wear as compared to Mo2C addition. The addition of ZrO2 was helpful to significantly improve the corrosion resistance of WC-Co-Cr coating whereas it decreases the erosion wear resistance of coating.

The Corrosion Erossion of Ship Propeller Al 7075 Produced by Gravity Sand Casting

Propeller is one of the important components of ships and boats that function as motor or boat propulsion. The mechanical properties required in propeller material are high toughness, easy to cast, and good engine capability, as well as good resistance to corrosion and erosion. One of the aluminum alloys that have been widely used in major vessels in propeller systems is the Nickel-aluminum-bronze (NAB) alloy because it has an excellent combination of mechanical properties and corrosion-erosion resistance. Another type of aluminum alloy that is widely used as a machining component is the Al 7075 T651 because it has the highest strength among other aluminum alloys. The mechanical properties of the Al 7075 T651 are directly proportional to the erosion resistance of the propeller which agrees with the pot tester porridge. The higher the value of the erosion propeller failure that occurs also increases with increasing testing rotational speed. For corrosion, a propeller with air testing media at a speed of 1000 rpm which results in significant corrosion products.&#x0D; Keywords: Al 7075 T651, Slurry Pot Tester, Corrosion Erosion

Effect of Microstructure and Hardness on Slurry Erosion Behaviour of A356 Alloy Using Slurry Pot Test Rig

A356 alloy is used in pump impeller, casing and pipes in power plant, naval, petrochemical and other applications where slurry erosion occurs. A356 hypoeutectic Al–Si Mg alloy has excellent castability and weldability with good resistance to wear and corrosion properties. The present study focuses on the effect of microstructure and hardness on slurry erosion wear behaviour of A356 alloy. The experiments were carried out on unalloyed A356 without stirring (WS), with stirring A356 (STIR) and the addition of strontium-modified A356 (SR) surface using slurry pot test rig. The indigenous-made laboratory-scale developed test rig was used for present investigation. Experiments were conducted at a constant velocity and constant concentration of solid particles of sample slurry under the impact angle ranging from 15° to 90° with high increment. A high-precision electronic weight balance was used to measure mass loss of the wear sample. The metallographic and material removal analyses were studied by using an optical microscope and scanning electron microscope. It was found that A356 (STIR and SR) alloys exhibited improved properties in terms of hardness and slurry erosion wear resistances than the A356 WS alloy.

Tribo-erosion performance of few HVOF coated micron layers subjected to equi-sized slurry particles

A comparative study on characteristic and erosion behavior of the 4 different high velocity oxy-fuel sprayed WC-10Co-4Cr, Colmonoy-88, Stellite-6 and Ni-Cr coatings on pump impeller stainless steel (SS 410) has been evaluated in the current investigation. First, the various micron layers were characterized by using energy dispersive spectroscopy (EDS), x-ray diffraction (XRD), scanning electron microscopy (SEM), micro hardness and micro roughness, and after that were subjected to erosion wear testing. Ducom slurry pot test rig with fly ash as erodent was used for erosion wear experiments, and the impact of four process parameters, namely, rotational speed, average particle size, solid concentration and time duration on slurry erosion of SS 410 were investigated. From erosion wear experimentation, it was concluded that the erosion wear highly depends upon the effecting parameters. The erosion resistance of coatings is found to be in following order WC-10Co-4Cr > Colmonoy-88 > Stellite-6 > Ni-Cr. It might be because of the higher hardness of WC-10Co-4Cr coating as compared to other coatings. Further the results show that the erosion wear of WC-10Co-4Cr, Colmonoy-88, Stellite-6 and Ni-Cr coatings was observed maximum at impact angle of 30°, 45°, 60° and 90° respectively.