Solid particle erosion (SPE) as a common damage mechanism in industrial applications can reduce the effective operation of components or contribute to failure. However, it has beneficial usages in manufacturing processes, especially in abrasive sandblasting and waterjet cutting. The aim of this paper is an investigation of erosive behavior of Ti-6Al-4V alloy through numerical and experimental approaches. A three-dimensional finite element (FE) model is developed using the representative volume element (RVE) to simulate multiple particles impact on Ti-6Al-4V target. Failure and plastic behavior of the target surface due to particles impact is described by Johnson-Cook constitutive equations. Furthermore, erosive behavior of the alloy is experimentally researched by multiple SPE tests. Verification of the implemented approach is studied by comparing the results of the FE model and the SPE experiments. Effects of particles impact angle considering Johnson-Cook coefficient values and particles velocity on erosive behavior of Ti-6Al-4V are also studied. Both numerical and experimental results show a maximum erosion rate of the alloy at an impact angle of 45 deg for spherical sand particles with a diameter of 100 µm. According to the scanning electron microscopy (SEM) images, the erosion process involves both ductile and brittle mechanisms at this angle.

The materials used for the slurry transportation system experience erosion wear due to the impact of suspended solid particles. In the present experimental investigation, a large size slurry pot tester was used to investigate the slurry erosion behavior of steel 304L, grey cast iron, and high chromium white cast iron in the velocity range of 9.0–18.5 m/s. Experiments were conducted by rotating the wear specimens in the pot tester at 1% weight concentration of Indian standard sand. The erosion behavior of the three target materials was evaluated by varying the orientation angle from 15 to 90 deg and particle size from 256 to 655 µm. The erosion rate was found to increase with velocity having power index value varying between 2 and 3, which increases with an increase in impact angle and depends on the target material. The erosion rate of the material also increases with the increase in particle size with the power index varying between 0.8 and 1.4 depending on the target material. No significant change was noticed in the mechanism of erosion of the target materials with the variation in velocity in the present range of test conditions. Empirical correlations are proposed to estimate the total erosion rate of all the three materials as a contribution of cutting and deformation wear.

This study presents the prehot corrosion effect on erosion behavior of AISI 446 SS in simulated heat exchanger environment at elevated temperature. Samples were spray deposited using two salt mixture (Na 2 SO 4 /NaCl). Subsequently, low-temperature hot corrosion tests were carried out at 550, 650, and 750 °C for 20 h. Chlorination followed by sulfidation was mainly responsible for the passive layer formation during the process of hot corrosion. The prehot corroded samples were subjected to air-jet erosion test using alumina as the erodent, at impact velocity of 100 m/s and flux rate of 4.2 g/min, with variable impingement angles of 30 deg, 60 deg, and 90 deg. The passive layer formed during corrosion underwent detachment of metallic flakes through cracking during the impact of erodent, and was responsible for a significant change in erosion rate. Cutting, plowing, lip formation, and particle embedment were identified as the operative mechanisms during erosion.

The erosion–corrosion (EC) and pure erosion of commercially pure titanium have been investigated in a 3.5% sodium chloride solution containing 10, 30, and 60 g/l SiO 2 particles with an average size of 318 μ m. The tests were performed at impact velocities of 4, 6, and 9 m/s under two impact angles of 40 deg and 90 deg. Polarization technique was used to study corrosion behavior of the material during erosion–corrosion. The eroded surfaces were examined by a scanning electron microscope (SEM) and a surface profilometer. The pure erosion, corrosion, and erosion–corrosion rates increased as impact velocity and sand concentration increased. The corrosion rates of the eroding surfaces under a normal impact were lower than those at an impact angle of 40 deg. The S/T ratio, i.e., the ratio of synergy to erosion–corrosion rates was about 80% at an impact velocity of 4 m/s, which indicated the high effect of the electrochemical corrosion on the degradation of CP-Ti at low velocity. The S/T ratio decreased to 30% and 15% at the impact velocities of 6 and 9 m/s, respectively. The S/T ratio was also decreased with increasing sand concentration indicating a greater role of mechanical degradation upon the erosion–corrosion rate in the concentrated slurries.

The effect of the gas-nitriding thermochemical treatment on the cavitation erosion resistance of a Cr-Ni-Mo alloy is analyzed using a piezoceramic vibrating equipment and following the ASTM G32-2010 standard. The evaluation of the cavitation erosion behavior was made based on the analysis of the mean depth of erosion (MDE) and mean depth of erosion rate (MDER), for samples subjected to the cavitation erosion for different times. The surface topography and the structural changes in the marginal layer were analyzed through optical and scanning electron microscopy. Following nitriding the cavitation erosion resistance was about 9.6 times higher compared to the annealed state and about 8.2 times higher compared to the hardened and tempered state.

The present experimental study investigates the effect of constant kinetic energy on erosion wear of aluminum alloy 6063. Three different natural erodents (quartz, silicon carbide, and alumina) with different particle sizes are used to impact at 45 deg and 90 deg impact angles. For calculating the number of particles in the slurry pot, it is assumed that the solid particles are of spherical shape. The total numbers of impacting solid particles were kept constant by adjusting the solid concentration, velocity, and test duration. The scanning electron microscope (SEM) images of the three erodents show that the alumina particles have sharp edges with more angularity, and silicon carbide particles have subangular nature while quartz particles are blocky in shape. The mass loss per particle at 45 deg impact angle is observed higher than at normal impact angle. It may be due to the change in material removal mechanism with changing the impact angle. It is also found that the mass loss per particle from the target material having different particle size with constant kinetic energy remains constant for respective erodents. This indicates that the velocity exponent of impacting particles is around 2. The SEM images of eroded surfaces reveal the different mechanisms of material removal at 45 deg impact angle and at normal impact angle.

This technical brief studied the cavitation erosion behavior of the silicified graphite. The phase constituents, surface microstructure, and chemical compositions of silicified graphite were examined by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS), respectively. Cavitation experiments were carried out by using an ultrasonic vibration test system. The experimental results show that the silicified graphite exhibits an excellent cavitation erosion resistance; this can be attributed to the fact that the silicified graphite has the characteristics of both the silicon carbide and the graphite. The SEM morphology studies of the erosion surfaces indicated that the inherent brittleness of SiC ceramic material results in the formation of erosion pits on the surface of silicified graphite.

High chromium white irons (HCCIs) are used extensively throughout the mineral processing industry to handle erosive and corrosive slurries. This study is an investigation of the effect of impact angle and velocity on slurry erosion of HCCI. The tests were carried out using a rotating whirling-arm rig with particle concentration of 1 wt. %. Silica sand which has a nominal size range of 500–710 μ m was used as an erodent. The results were obtained for angles of 30 deg, 45 deg, 60 deg, and 90 deg to the exposed surface and velocities of 5, 10, and 15 m/s. The highest erosion resistance of HCCI was at normal impact and the lowest at an angle of 30 deg, irrespective of velocity. The low erosion resistance at an oblique angle is due to large material removal by microcutting from ductile matrix and gross removal of carbides. The effect of velocity, over the studied range from 5 m/s to 15 m/s, on the increase in the erosion rate was minor. The change of impact velocity resulted in changing the slurry erosion mechanisms. At normal incidence, plastic indentation with extruded material of the ductile matrix was the dominant erosion mechanism at low impact velocity (5 m/s). With increasing impact velocity, the material was removed by the indentation of the ductile matrix and to smaller extent of carbide fracture. However, at high impact velocity (15 m/s), gross fracture and cracking of the carbides besides plastic indentation of the ductile matrix were the dominant erosion mechanisms.

In this study, the effect of flow velocity (4–7.5 m s −1 ) and impact angle (30–90 deg) on erosion–corrosion behavior of chromium carbide coating was investigated under impingement by silica containing NaCl solution. Chromium carbide coating was deposited on low carbon steel by thermal reactive deposition/diffusion method at 1050 °C for 12 h in a molten salt bath. Mass loss measurement and potentiodynamic polarization tests were employed in order to determine coating performance under impingement. Polarization curves showed that the coated samples had less corrosion current density and high chemical stability. High mass loss at low impact angle indicated ductile behavior for the uncoated sample, while the mass loss for the coated sample changes less than 30% with impact angle up to 60 deg. Furthermore, the erosion–corrosion behavior of the coated sample was slightly dependent on flow velocity. Scanning electron micrographs showed that at lower impact angle, the Cr 7 C 3 coating eroded with flake fragmentation mechanism, while at high impact angle, fatigue fracture is the main degradation mechanism.

In the present work, the image features of cavitation erosion surfaces at different temperatures are extracted using wavelet decomposition transform. The results obtained indicate that the extract parameters, wavelet energy, and entropy can characterize the cavitation intensity in a similar manner to that of the mass loss and average particle size at different temperatures. Based on the analysis of the eroded surface and particle morphologies for different temperatures, it was found that the predominant failure mode was fatigue.

A slurry impingement rig containing 6 wt.% SiO 2 particles was used to investigate synergistic erosion–corrosion behavior of X-65 carbon steel at various impingement angles. Maximum erosion–corrosion and erosion rates occurred at impingement angles of about 25 deg and 40–55 deg, respectively. The synergy value highly depended on the impingement angle. The formation of patches of porous corrosion product followed by the formation of corrosion pits led to a positive synergy under impingement angle of 25 deg. At higher impingement angles, the absence of pits probably due to the formation of a more durable tribocorrosion layer resulted in a negative synergy.

In this technical brief, a Cr 3 Si nanocrystalline film was deposited on 304 stainless steel (SS) substrate using a double glow discharge plasma technique. The film was characterized by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy, nanohardness tester, and scratch tester. The as-deposited film with a thickness of 5 μ m consisted of A15 structured Cr 3 Si phase with an average grain size of 8 nm. The hardness values of the film were determined to be 26 GPa, which was ten times greater than 304 SS. A self-designed ultrasonic vibration cavitation erosion apparatus was employed to evaluate the cavitation erosion resistance of the Cr 3 Si film. The results showed that after cavitation tests of 30 hrs, the erosion mass loss of the film was only 60% of that for 304 SS substrate. SEM observation of the erosion surfaces indicated that the surface damage degree of the Cr 3 Si film is significantly less than that of 304 SS.

Solid particle shape and size effects on the slurry erosion behavior of AISI 5117 carbon steels are investigated, using whirling-arm ring for two different erodent particles, namely, silica sand (SiO 2 ) and silicon carbide (SiC). From this work, it was found that aspect ratio and circularity factor (CF) increase for silica sand and decrease for silicon carbide with increasing size. The erosion rate increased with the increase of particle size for the two types of erodent particles and its value was greater in the case of silicon carbide particles. At the same test conditions, it has been noticed that the particle size plays the major role in the slurry erosion of 5117 steels in comparison with the aspect ratio and circularity factor. Microcutting and plowing with serrated wear tracks were observed for coarse SiC particles having irregular and angular shape. But, for coarse SiO 2 particles which had a rounded shape, the main mechanism was plowing with plain and smooth wear tracks for an impact angle of 30 deg. Indentations and material extrusion prevailed for the coarse size of the two erodents for an impact angle of 90 deg.

Pipelines are the most flexible, economic, and convenient way for oil and gas transportation. Material degradation by slurry erosion is a common feature in oil transmission pipeline. In the present work, slurry erosion of AISI 1018, AISI 1080, API X42, and API X70 steels is investigated in terms of slurry velocity and target material microstructure. The slurry velocity and impact angle employed were 0.2, 0.29, 0.36, and 0.43 m s −1 and 90 deg, respectively. It is found that erosion rate increases with increasing slurry velocity. Scanning electron microscopy was employed to investigate the eroded surface and subsurface of the steels. Plastic deformation, microcutting, and fracture are identified as dominant erosion mechanisms. Pearlitic microstructure exhibits superior erosion resistance compared to ferrite depending upon slurry velocity and microstructural orientation.

Erosion, erosion–corrosion, and synergistic behaviors of AISI 420 stainless steel were studied in 3.5 wt.% NaCl solution containing silica sand with the size of 250–500 μm as erodent particle. The erosion and erosion–corrosion tests were carried out according to ASTM G11909 standard and the synergism was calculated. The tests were performed using a slurry jet apparatus at a jet velocity of 6.5 m/s, sand concentration of 90 g/l, and various impinging angles of 20 deg–90 deg. Scanning electron microscope (SEM) was used to study the eroded surfaces and erosion mechanisms. The SEM images showed that under low impacting angles, cutting deformation was the main erosion mechanism while impact and work hardening could be responsible for material removal at high impacting angles. The results showed that the maximum erosion–corrosion and synergism rates occurred at an impingement angle of about 50 deg while the maximum pure erosion rate was obtained at impingement angle of about 35 deg. Energy dispersive spectrometry (EDS) analysis showed that an oxide layer was formed on the surfaces of the samples during erosion–corrosion tests. This oxide layer could make the surface more brittle and could lead to an increment of about 15 deg in the angle of the maximum removal rate. The formation and the subsequent removal of the nonprotective oxide layer as well as possible initiation and propagation of pits during erosion–corrosion tests could lead to higher erosion–corrosion rate compared to pure erosion resulting in a positive synergism under the conditions tested.

The erosion–corrosion (E–C) wear behaviors of electroless nickel phosphorus (Ni-P) coating, carburizing and untreated low alloy steel AISI 5117 in water–sand slurry and saline–sand slurry were investigated using whirling-arm tester. The E–C wear mass loss was measured to evaluate the effect of mediums and surface modifications. The microstructure of carburizing and Ni-P coating was analyzed using an optical and scanning electron microscope (SEM) and X-ray diffraction (XRD) technique. Results showed that Ni-P coating and carburizing are effective in increasing wear resistance of low alloy steel. However, the Ni-P coating is more effective in increasing the E–C resistance. Also, the results showed that Ni-P coating, carburizing and untreated carbon steel behaved as ductile materials under erosion and E–C tests, and the maximum mass loss occurred at an impact angle of 45 deg. The synergism ratio was the lowest for the Ni-P coating, indicating that Ni-P coating improved an anti-E–C wear resistance.

This paper presents an approach to establish the model for predicting the steady-state erosion rate of polyetherimide and its glass fiber composites. Three-factor and two-level, face-centered composite design is used for experimentation. The parameters which affect the erosion rate are selected as glass fiber percentage (0–40%), impingement angle (30 deg–90 deg), and impact velocity (30–90 m/s). Response surface methodology is used to derive second-order quadratic model with interactions. Investigation showed all the parameters have significant effect on controlling steady-state erosion rate of these composites. The interactions of impact velocity-fiber percentage and impact velocity-impingement angle are significant. The increase in erosion rate with the increase in impact velocity is found to be satisfying a power law. Maximum erosion rate for these composites found at around 45 deg–60 deg impingement angle indicates their semiductile erosion behavior. Scanning electron microscopy photographs indicate ploughing, microcutting, development of cracks, and exposure of fibers as the dominating erosion mechanisms for these composites.

This study describes the development of a multicomponent composite system consisting of thermoplastic epoxy resin reinforced with E-glass fiber and silicon dioxide (SiO2) particles and investigates its erosion behavior under different operating conditions. Due to the increasing importance of composites in engineering applications and the need to tackle solid particle erosion in various industrial sectors, the study aims at finding how these composites behave in such type of wear. The composite specimens used for the tests were classified into three types; pure glass fiber (GF)–epoxy, those with addition of SiO2 particles at an amount of 15% and the last group had SiO2 particles added at 30% of the resin used for the materials. The experiments were carried out by selecting three different impact velocities, three different impingement angles, and angular alumina abrasive particles having approximate sizes of 200 μm. The fiber directions used were 0/90/0 and 45/ − 45/45. SEM views belonging to the specimens were taken before and after the tests in order to investigate the differences and the causes of the surface damages. Moreover, it is found that the Taguchi's robust orthogonal array method provides a simple, systematic, and efficient methodology for the optimization of the erosion wear parameters. At the end of the tests, the most significant factor in affecting the erosion rate is found to be the impingement angle, followed by the impact velocity, fiber direction, and filler material.

In the present work, the slurry erosion behavior of friction stir processed (FSPed) hydroturbine steel (CA6NM) was investigated. For comparison, the erosion performance of unprocessed CA6NM steel was evaluated under similar conditions. Friction stir processing (FSP) is a microstructural refinement tool which is useful in enhancing the bulk and surface properties of materials. An in-depth characterization of both steels was done using an optical microscope (OM), a scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS), the electron backscatter diffraction (EBSD) technique, and micro- and nano-indentation techniques. The FSP of the steel helped in reducing the erosion rates by 50% to 60%, depending upon the impingement angle. The improved performance of the FSPed steel in comparison to unprocessed steel was attributed to microstructural refinement, which increased the hardness and yield strength. At an oblique impingement angle, plowing, along with microcutting, was observed to be the dominant erosion mechanism. At a normal impingement angle, the material removal process was controlled by the platelet mechanism of erosion. A modified form of the mathematical model for predicting the erosion rates of the ductile materials, proposed by authors earlier, was also presented. This modified model based upon the theory of plasticity was able to predict the erosion rates with an accuracy of ±20%.

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.