Slurry Erosion Conditions Research Articles

The Influence of Impact Velocity on Stresses and Failure of S355j2 Steel Under Slurry Erosion Conditions

The Influence of Impact Velocity on Stresses and Failure of S355j2 Steel Under Slurry Erosion Conditions

Slurry erosive wear behaviour of metal matrix composites – A review

Slurry erosion has become a problem in the components that handle particle-entrained slurry. The limitation of the metallic materials to inhibit the slurry erosive wear has led to the development of metal matrix composite (MMC) materials to suit applications in severe erosive environments. Compared to ductile and brittle materials, metal matrix composite materials behave differently when subjected to slurry erosion. However, due to the ductile matrix and hard reinforcement phases, the metal matrix composites exhibited semi-ductile and semi-brittle erosion behaviour under slurry erosion conditions. This work presents the material removal mechanisms of MMCs, erosion models, and types of equipment for slurry erosion testing. In addition, the various factors that influence slurry erosion, such as the properties of MMC, properties of flow, erodent particles, and slurry, have also been reviewed.

Slurry Jet Erosion Resistance of VC-Containing Tool Steels: the Role of the Carbide Volume Fraction

Tool steels are well known to have superior strength and are claimed to have superior wear resistance than conventional steels in several scenarios. However, their behavior under slurry erosion conditions have been seldom studied. To this end, a set of tool steels, primarily from the CPM yV (y = 1, 3, 9, 10, 15) alloy family, was selected to understand the effect of hardness and vanadium carbide content on the slurry jet erosion (SJE) performance at different impingement angles. It was observed that the SJE resistance increases with the increase in the vanadium carbide volume fraction, but is independent of alloy hardness.

Performance of Thermally Sprayed Nickel and Tungsten-Based Coatings in Slurry Erosion Conditions: A Review

Abstract The energy needs of a country cannot be fulfilled by a single source of energy, so renewable energy sources like solar, wind, and hydro energy are widely used throughout the world. In countries where sufficient hydro energy resources are available, hydropower plants have been installed to produce electricity. But countries where the rivers originate from hilly areas (like India and Nepal) have to deal with the losses due to the wear caused by the silt particles presented in water. The silt content in water causes the erosion of material in different components of hydropower plants. To avoid these losses thermally sprayed hard surface coatings are widely used as a protective layer. This review focuses on the performance of composite coatings based on nickel and tungsten in slurry erosion conditions. A comprehensive investigation of studies conducted on thermally sprayed nickel- and tungsten-based coatings is discussed in this review paper. The review reveals that high velocity oxy-fuel is widely used by different researchers to develop composite coatings. Materials like Ni–20Cr2O3, Ni–Al2O3, Ni–Cr–Si–B, WC–10Co, WC–10Co–Cr, and Ni–Cr–B–Si–Fe–WC (Co) have been used in different studies to minimize the wear of material in slurry conditions.

Investigations on erosion performance of carbon fiber–epoxy-based composite adhesion on 16Cr5Ni steel

This work presents a novel insight into slurry erosion behavior of thin layer of carbon fiber–epoxy-based composite adhered on 16Cr5Ni steel (adhesive coating) to evaluate its viability as a feasible candidate for slurry erosion applications. Experiments were conducted on a laboratory-developed slurry erosion test rig under accelerated conditions to study the effect erosion parameters namely slurry concentration, impact angle, and impact velocity. Under all the experimental conditions, adhesive coating showed better slurry erosion resistance in comparison with bare 16Cr5Ni steel specimens. Scanning electron microscopy analysis revealed that in the case of bare 16Cr5Ni steel; ploughing, micro-cutting, crater, plastic deformation, and lip formation were identified as main mechanism responsible for slurry erosion, whereas in the case of adhesive coating; pitting, cracking, fracturing, and shearing-off were found to be mainly responsible for material loss. It implies that adhesive coating showed a brittle mode of failure under slurry erosion conditions, whereas 16Cr5Ni steel exhibited a ductile mode of erosion.

Comparison of erosion performance of uncladded and WC-based laser cladded SS304 and SS410 steels

Myriad hydro materials have been encountered with the severe attacks of eroded particles during the operation, leading to degradation of target material and economic loss. In this study, Colmonoy-6+WC powders were deposited with the help of the laser cladding method on the bare SS304 and SS410 steel surfaces. Distinct properties of cladded surfaces, such as mechanical as well as metallurgical properties, were investigated. The influence of slurry erosion parameters like angle of impact and impact velocity of eroded particles on the cladded as well as uncladded steel specimen was analysed. Under all slurry erosion conditions, there was an escalation in slurry erosion resistance in the case of cladded steel as that of as-received steel specimens. In slurry erosion, the influence of the impact velocity of erodent particles is more against the impact angle. The scanning electron microscopy images of eroded uncoated steel specimens represent ductile behaviour along with the formation lip, ploughing etc., while eroded cladded steels exhibit brittle behaviour.

Erosion behavior of laser cladded Colmonoy-6 + 50%WC on SS410 steel under accelerated slurry erosion testing

Erosion due to slurry has an indispensable effect on the lifespan and operating efficiency of hydro machine components. To mitigate this effect, laser cladding may prove as a cost-effective choice to improve the surface properties of various hydro machine components. In this research work, a laser cladding of Colmonoy-6 + 50%WC powder on the surface of SS410 steel was deposited using high-power diode laser at optimized levels of operating parameters. The deposited coating was characterized with regard to different mechanical and metallurgical properties. The effect of various factors such as slurry concentration, erodent particle size, impact velocity, and impact angle on slurry erosion behavior of uncoated and laser cladded substrate was analyzed. The Colmonoy-6 + 50%WC cladded specimens exhibited significantly better slurry erosion resistance in comparison with uncoated SS410 steel specimens under all slurry erosion conditions. Impact velocity was observed to be a maximum contributor to slurry erosion, followed by impact angle, average particle size and slurry concentration. The SEM micrographs of eroded cladded surfaces showed signatures of lip formation & fracture sites, micro-cutting, ploughing, and wear marks at a shallow impact angle in Colmonoy-6 pool, however, for normal impact, the existence of cracks in WC particles were observed.

Investigating slurry erosion behavior of a hydro-machinery steel under various impingement variables

SS410 is widely used as a hydro-machinery steel and is generally exposed to the slurry erosion conditions, which decrease its useable-life. In the current investigation, an attempt was made to analyse the effect of slurry erosion on this steel. The slurry erosion testing was done in a slurry erosion test rig, which provides possibility to vary impingement conditions like average particle size, slurry concentration, impingement angle, and velocity of jet. Moreover, some mechanical and metallurgical properties of the steel were also investigated. It was concluded that the slurry erosion rate of the steel increases with increase in the concentration and jet velocity. However, with the increase in average particle size, slurry erosion was found to decrease, which may be due to the lower penetration capacity of higher sand particles. Moreover, slurry erosion, in general, was found to be maximum at a parametric combination of lowest average particle size (150 µm), 60° impingement angle, maximum concentration (45000 ppm), and maximum jet velocity (35 m/sec). Slurry erosion was found to be maximum at an impingement angle of 60°, indicating a mixed mode of erosion (ductile as well as brittle) for the given steel. The mechanisms involved in slurry erosion were found to be crater formation, ploughing, and lip formation followed by its fracture.

Erosion studies of the iron boride coatings for protection of tubing components in oil production, mineral processing and engineering applications

Heavy oil production, oil sand and mineral processing require protection of steel components against sand erosion and erosion-corrosion. Boronized coatings on carbon steels obtained through thermal diffusion process were evaluated in the dry sand and slurry erosion conditions at low impingement angles commonly occurred in industrial applications. The specially designed system allowed testing either multiple sets of samples or full-size tubular sections with diameters of 180–220 mm. The boronized coatings consisted of dual iron boride layers FeB and Fe2B with a total thickness of ~200 μm demonstrated significantly higher erosion resistance over carbon steel commonly used in industry. High performance of the boride coatings is defined by their high hardness, dual protective layer with a well-consolidated structure and diffusion related bonding with steels. Erosion wear mechanism is discussed based on examination of coating's structure and composition and analysis of testing conditions. The components and tubing with inner or inner and outer protective iron boride coatings can be successfully employed in downhole oil production conditions, mineral processing and various engineering applications.

Tribological investigation of HVOF-spray Cr3C2-25NiCr and WC-10Co-4Cr coated turbine steel under varied slurry erosion conditions

In this work, high velocity oxy fuel (HVOF) method based spray coatings namely Cr3C2-25NiCr and WC-10Co-4Cr have been deposited on AISI304 turbine steels. An attempt has been made to analyze the coatings under accelerated slurry erosion conditions by employing a laboratory-developed slurry erosion testing set-up. The testing has been performed under varied conditions of slurry concentration, impact velocity and impact angle using the Taguchi approach. The microstructure of coating powder, erodent particles and deposited coatings have been studied using a scanning electron microscope (SEM) analysis. Erosion tests indicated that HVOF-spray Cr3C2-25NiCr and WC-10Co-4Cr coatings have been deposited on AISI304 steel exhibited significant improvements in the erosion resistance of AISI304 steel. The possible reason for such behaviour could be higher microhardness of HVOF-spray coatings in comparison with AISI304 bare steel. From SEM images of the samples taken prior and post slurry erosion tests, it has been observed that Cr3C2-25NiCr coating exhibited mixed (ductile and brittle) behaviour, though the WC-10Co-4Cr coating mostly demonstrated ductile behavior under conditions for erosion from the slurry. Apart from that, an attempt has been made to develop a functional equation based on the regression approach which could be employed to assess the erosion wear rate under a set of conditions. The predicted erosion wear results under varied conditions are in close relationship to experimental values.

Slurry Erosion Behavior of HVOF-Sprayed WC-10Co-4Cr Coated SS 316 Steel with and Without PTFE Modification

Several hydro-machinery components such as impellers of the submersible pump and turbine blades generally suffer from slurry erosion during their operation. High-velocity oxy-fuel (HVOF)-sprayed coatings are promising materials to prevent such components from slurry erosion. Moreover, polytetrafluoroethylene (PTFE) is a well-accepted hydrophobic material, which has several attractive properties such as chemical inertness and considerable thermal stability. Therefore, PTFE coating has been explored as a topcoat for a HVOF-sprayed WC-10Co-4Cr coating, with an aim to enhance the performance of the latter and analyzed with different slurry erosion conditions. A slurry erosion test rig was used for experimentation, and the effect of four different erosion parameters, namely average particle size, slurry concentration, impact angle, and velocity of jet, was investigated. A comparative study between PTFE-modified HVOF-sprayed coating and the standalone HVOF-sprayed coating was also done with respect to slurry erosion behavior and hydrophobicity. The overall results indicate that the slurry erosion of the HVOF-sprayed coated SS 316 steel got enhanced after modification by PTFE topcoat. Furthermore, the topcoat of PTFE on HVOF-sprayed coating resulted in a remarkable improvement in hydrophobicity, showing a superhydrophobic behavior, which might have also provided a better slurry erosion resistance to the HVOF-sprayed steel.

Characterization and Accelerated Erosion Testing of WC-Co-Cr- and CoNiCrAlY-Coated CA6NM Turbine Steel

In the present study, in-depth characterization of the high-velocity oxy-fuel (HVOF)-spray WC-Co-Cr and CoNiCrAlY coatings deposited on CA6NM turbine steel was done using scanning electron microscope (SEM), x-ray diffraction (XRD), roughness tester, microhardness tester, and optical image analyzer. Further, these coatings were tested under accelerated slurry erosion conditions using a high-speed erosion test rig. The effects of three different parameters related to actual operating conditions, namely erodent velocity relative to target surface, average erodent particle size, and slurry concentration on erosion behavior of these coatings, were investigated. SEM images on the specimen surface taken before and after erosion tests were carefully examined to understand the possible erosion mechanism. The study revealed that HVOF-sprayed WC-Co-Cr coating was found to impart higher erosion resistance in comparison with CoNiCrAlY coating under all the slurry erosion conditions. The reason for this behavior may be attributed to the higher hardness of HVOF-sprayed WC-10Co-4Cr coating in comparison with CoNiCrAlY coating.

Numerical Investigation of Slurry Erosive Wear Due to Multiple Particle Impact

In the present work, an attempt has been made to investigate the slurry erosion problem using numerical simulation approach. AISI304 steel has been chosen as the base material for the present study. Performance of AISI304 steel under the range of slurry erosion conditions such as an impact angle and impact velocity of the erodent particles are investigated using laboratory developed slurry erosion test rig. To simulate the similar conditions virtually as available in the hydropower plant, finite element analysis software named as Abaqus has been used. Model has been developed using explicit dynamic solver approach. For correlating the behavior of the material with real time conditions, Johnson cook material model and failure model has been used. To simulate the solid particles impact, general contact penalty method has been adopted. Erosive wear rate is correlated with material removal rate and depth of penetration. It has been observed that the simulated results using Abaqus explicit are in confirmation with the experimental results. Furthermore, to analyze the mechanism of erosion, substrate surface was analyzed with reference to stresses and plastic strains developed by the impact of erodent particles.

The Effect of pH on Slurry Erosion–Corrosion of Tungsten Carbide Overlays Alloyed with Ru

The aim of the study was to determine the effect of Ru additions to WC-Fe overlays when exposed to low pH slurry erosion conditions. These overlays were applied through Plasma Transferred Arc, and the original bulk Ru powder concentrations varied from 0.5 to 5 wt.%. A slurry jet impingement erosion–corrosion test rig was used to evaluate wear, and electrochemical measurements were performed to characterize the corrosion properties. The slurry mixtures contained silica sand and synthetic mine water. The pH was varied between 3 and 6.5 for the slurry erosion tests and lowered further for the corrosion characterization. Samples were examined optically and with a scanning electron microscope using energy-dispersive x-ray spectroscopy. X-ray diffraction analysis was used to determine the phases present. For the slurry erosion–corrosion results at the pH of 6.5, addition of Ru did not show a decrease in erosion–corrosion rates. However, when the pH was decreased to 3, by the addition of HCl, Ru improved the resistance. From the electrochemistry, it was also clear that Ru additions improved the corrosion resistance, but more than 1 wt.% Ru was required. At very low pH levels, the presence of Ru was not able to prevent corrosion.

Performance evaluation of HVOF deposited cermet coatings under dry and slurry erosion

The present work reports on the examination of three High Velocity Oxy Fuel deposited coatings, Tungsten Carbide, Chromium Carbide and Aluminium Oxide, under slurry erosion and dry erosion conditions. The density and hardness of coatings produced in this manner are typically superior to other thermal spray processes, and are therefore suitable for use in corrosive and highly erosive environments. The primary aim of this investigation was to establish the total mass and volume loss from each coating under dry and slurry erosion testing conditions and compare the level of material loss following the respective testing regimes. The scope of the study incorporated the application of cathodic protection to prohibit the effects of corrosion in the case of slurry erosion testing. This approach ensured that any damage to the surface could be attributed to pure erosion, and as such, be assessed against the dry erosion test data. Subsequent examination of the resulting wear scars facilitated assessment of the level of damage caused by the impinging slurry. Results revealed variation in the level of degradation experienced by each coating type under the respective test conditions. Under both dry erosion and slurry erosion, Tungsten Carbide with a Cobalt binder proved an effective protective coating by exhibiting a reduction in material loss over other assessed coatings.

Wear performance of quenched wear resistant steels in abrasive slurry erosion

Three commercially available quenched wear resistant steel grades were compared with a structural steel and four elastomer materials to reveal the differences in their behavior in slurry erosion conditions and to find the best solutions for demanding applications. A slurry-pot tester, allowing simulation of various wear conditions with different minerals, particle sizes (up to 10mm), abrasive concentrations, and sample angles were used to simulate different industrial slurry applications. In this study, granite and quartz with concentrations of 9 and 33wt% were used as abrasives in tests conducted at 45° and 90° sample angles. The performance of the studied steels was evaluated with respect to their material properties such as hardness and microstructure. Furthermore, the cross-sections and wear surfaces of the test samples were analyzed to reveal the possible differences in the mechanical behavior of the materials during slurry erosion. The wear surface analyses show that abrasion is the dominating wear mechanism already for the smallest particle size of 0.1/0.6mm. In low-stress abrasive slurry erosion with the smallest particles, the elastomers showed better wear resistance than the steels, whereas in demanding high-stress abrasive slurry erosion conditions the quenched wear resistant steels can well compete with elastomers in wear resistance. The relative wear performance of the steels increased with increasing abrasive size, while for the elastomers it decreased.

Effect of tribometer configuration on the analysis of hydromachinery wear failure

Slurry erosion and cavitation erosion tribometers are used to evaluate wear on materials of hydromachinery components, in this work numerical simulations based on computational fluid dynamics (CFD) were implemented with the aim to analyze the influence of parameters such as shape and size of cavitation inducers, rotational speed, particle concentration and cavitation inducer-specimen separation over the mass loss rate. Operating parameters were determined, which are suitable to reproduce typical cavitation erosion and slurry erosion conditions presented in turbomachinery devices like Francis turbine runners under off-design conditions or exposed to a high amount of sediments. CFD analysis provides a numerical insight about the flow field and its behavior due to the influence of shape and location of the cavitation inducers aiming to predict the zone where the cavitation process takes place. Also, it was found that CFD simulation coupled with particle tracking methods provide an understanding about the interaction between the hard particles and the surfaces tested, and its influence over erosion rates.

Erosive Wear Study of HVOF Spray Cr3C2–NiCr Coated CA6NM Turbine Steel

Degradation of surfaces of hydroturbine components caused by impact of abrasive particles carried by flowing water is a serious issue. To counteract the same, surface modification of turbine materials by the application of protective coatings is gaining popularity these days. In this work, Cr3C2–NiCr coating was deposited on CA6NM turbine steel by the HVOF spray process and studied with regard to its performance under different slurry erosion conditions. The effect of three parameters, namely average particle size of slurry particles, speed (rpm), and slurry concentration on slurry erosion of this coating material, was studied by using a high speed erosion test rig. The analysis of the surfaces of the samples before and after slurry erosion tests was done by using SEM. The HVOF sprayed Cr3C2–NiCr coating showed very good performance under slurry erosion in comparison with uncoated CA6NM steel.

Degradation process of typical Ti(C,N)–Mo2C–Ni cermet in slurry erosion conditions

Degradation process of Ti(C,N)-based cermet is investigated in solid–liquid erosion conditions. The results indicate that the erosion process of Ti(C,N)-based cermet is classified into incubation, development and prevalence. In the incubation stage, the weight loss is dominated by binder deterioration; in the development stage, ceramic phase and binder failure contribute to the material loss; and in the prevalence stage, ceramic fragments removal is responsible for the material loss. Impingement of Al2O3 particle results in ceramic phase deterioration, while in binder the degradation is caused by impingement and microcutting. Microcracks nucleate firstly at the interface and/or in the rim phase.

Slurry Erosive Wear Evaluation of HVOF-Spray Cr2O3 Coating on Some Turbine Steels

In this study, Cr2O3 coatings were deposited on CF8M and CA6NM turbine steels by high-velocity oxy-fuel (HVOF)-spray process and analyzed with regard to their performance under slurry erosion conditions. High Speed Erosion Test Rig was used for slurry erosion tests, and the effects of three parameters, namely, average particle size, speed (rpm), and slurry concentration on slurry erosion of these materials were investigated. SEM micrographs on the surface of samples, before and after slurry erosion tests, were taken to study the erosion mechanism. For the uncoated steels, CA6NM steel showed better erosion resistance in comparison with CF8M steel. The HVOF-sprayed Cr2O3-coated CF8M and CA6NM steels showed better slurry erosion resistance in comparison with their uncoated counterparts. It may be due to the higher hardness as a result of HVOF-sprayed Cr2O3 coating in comparison with the uncoated CF8M and CA6NM steels.