High Temperature Erosion Tests Research Articles

High-temperature erosion behavior of Al2O3 reinforced Inconel625 high velocity oxy-fuel sprayed and direct-aged composite coatings

In this study, Inconel625+30%Al2O3 (IN30AL) blended powders were sprayed on a commercially used boiler steel ASTM SA210 GrA1 using high-velocity oxy-fuel approach (HVOF). The microstructure, mechanical properties and elevated temperature erosion behavior of post-processed coatings and as-sprayed IN30ALcoatings were investigated. The elevated temperature erosion studies on IN30AL coatings both as-sprayed and post-processed were investigated at 900 °C temperature at two impact angles 30° and 90° using standard high temperature erosion test rig. Phase composition, interface of substrate/coating, and morphologies of eroded coatings were examined using x-ray diffraction, x-ray maps, scanning electron microscope, & energy dispersive spectrometer techniques. Compared with the as-sprayed IN30AL coatings, the heat-treated coatings have refined microstructure, better mechanical properties which improve the elevated temperature erosion resistance of IN30ALcoatings.

Numerical simulation of high-temperature erosion of heat-resistant steel considering surface scale evolution

A study was conducted on heat-treated, heat-resistant steel S51740 to understand the issues surrounding gas turbine compressors. The study included high-temperature cyclic oxidation and high-temperature erosion tests at 400 °C, 600 °C, and 800 °C. We used the oxidation test data to establish dynamic erosion models using Ansys LS-DYNA software. We focused on the target's surface morphology, stress-strain, transient temperature, and failure characteristics during high-temperature erosion after high-temperature oxidation to reveal the erosion mechanism of oxidized steel. During cyclic oxidation, the specimen's microstructure was refined at 400 °C, with a 10 μm oxidation-affected zone emerging. At 600 °C, austenite appeared, forming a 20 μm oxidation-affected zone. Performance declined at 800 °C due to decarburization and segregation, resulting in a 50 μm oxidation-affected zone. High-temperature erosion on the oxidized specimens featured cutting and a chip-like morphology at 400 °C and 600 °C. At 800 °C, the specimen experienced a notable increase in mass loss and extensive plastic deformation on the surface. Erosion simulations revealed that rising temperatures increase the target's stress distribution, strain, and temperature zones. Reduced material strength leads to lower resistance to impact particles, converting high-speed kinetic energy to internal energy during erosion. Temperature spikes in impacted zones accelerate wear and adversely affect local mechanical properties. Lower ambient temperatures exacerbate the temperature increase from erosion, significantly influencing material erosion and wear resistance.

High-Temperature Solid Particle Erosion of Aerospace Components: Its Mitigation Using Advanced Nanostructured Coating Technologies

Solid particle erosion of gas turbine blades in the aerospace sector results in increased maintenance costs, high pollution, reduced engine efficiency, etc. Gas turbines in aircraft are usually operated at high temperatures. Based on the compressor stage, the temperature varies from 100–600°C, whereas turbine blades, after combustion, experience a very high temperature between 1000–1400 °C. So, a better understanding of temperature-dependent solid particle erosion is required to develop suitable solid particle erosion-resistant coatings for gas turbine blades. In this review, a detailed overview of the effect of temperature on the solid particle erosion process and different types of erosion-resistant coatings developed over the last four decades for compressor blades are discussed in detail. In the initial sections of the paper, solid particle erosion mechanisms, erosion by different erodent media, and the influence of erosion on gas turbine engines are discussed. Then, the erosion rate trend with increasing temperature for ductile and brittle materials, high-temperature erosion tests in a corrosive environment, and the role of oxidation and bonding nature in high-temperature erosion are examined. In most cases, the erosion rate of materials decreased with increasing temperature. After this, the evolution of erosion-resistant coatings over the last four decades that are first-generation (single-phase coatings), second-generation (metal/ceramic multilayer coatings), and third-generation (nanocomposite and nano-multilayer coatings) erosion-resistant coatings are reviewed in detail. The third-generation nano coatings were found to be superior to the first- and second-generation erosion-resistant coatings. Finally, some of the commercial or notable erosion-resistant coatings developed in the last decade are discussed. The paper concluded with the research gaps that need to be addressed to develop efficient erosion-resistant coatings.

Analysis and prediction of erosion behavior of short kenaf fiber‐based hybrid composites using response surface method integrated with neural networks

AbstractThere has been a huge demand in industries for the design and development of bio‐degradable and low‐cost wear resistant composite materials since long. In response to this, the present work includes an exhaustive analysis for the solid particle erosion characteristics of a new class of hybrid polyester composites reinforced with a natural fiber (kenaf) and filled with a construction waste (marble dust) in different proportions. The test trials on the composite samples are conducted using a DUCOM high temperature erosion test rig as per ASTM G76. The experimentation and analysis are conducted as per the L30 model of response surface method (RSM). The results revealed that the incorporation of marble dust enhanced the resistance to erosion wear of the fiber‐polyester composites and among the control factors, the contributions of striking velocity and angle of impingement towards the erosion rate are significant. A predictive model working on the concept of neural networks (ANN) is used for the prediction of erosion rates at different levels and combinations of the significant control factors. The mechanisms of erosion loss are identified from the morphologies of the worn surfaces taken using a scanning electron microscope.

High-temperature erosive wear characteristics and bonding requirements of hard carbides cast-in insertion multi-component white cast iron

This research investigated wear resistance characteristics of hard carbide cast-in insertion cast iron by high-temperature erosive test. Moreover, good bonding conditions between cast iron and hard carbide alloy were examined by using casting simulation CAE. Two types of multi-component white cast iron with Cr, Mo, W, V, and Nb for base metal, tungsten carbide (WC) and titanium carbide (TiC) for insert were prepared. High-temperature erosion tests were conducted using alumina ball (average diameter: 1.16 mm, hardness: 1140 HV) with impact angle of 30, 60, and 90 deg. at 873 K.The air velocity of 100 m/s (particle velocity about 30 m/s). The total particle loading was 8 kg. The mass of the test specimen was measured before and after each test to evaluate the erosive wear property by erosion rate which is volumetric removal divided by the total feed of impact particles.As a result of erosion tests, WC cast-in insertion multi-component white cast iron showed good wear resistance characteristics compared with TiC one. TiC cast-in insertion multi-component white cast iron increased wear amounts due to cracking on insert surfaces that occurred by heat shock when pouring.Temperature history of interfacial molten cast iron and insert on solidification process were acquired by using solidification analysis to compere condition of molten steel and insert at the bonding interface. To longer liquid phase contact time is the thicker diffusion and reaction layer of each cast-in insertion sample. Both diffusion and reaction layers were created in the bonding interface of WC cast-in insertion sample. On the other hand, only diffusion layer was created in TiC cast-in insertion sample. These differences in bondability are due to diffusion coefficient of insert elements and gibbs standard free energy of carbides.

Study on High-temperature Erosion Resistance of Precursor Ceramic Coatings

Given the high-temperature chlorine corrosion in the process of waste incinerators, polysilazane was used as the precursor, and glass powder and zirconia were added as fillers to prepare composite ceramic coating on TP347 substrate. In this paper, the effect of temperature on the formation of voids in the coating was studied by microscopic analysis. The high-temperature erosion wear resistance of the coating was also tested. The results show that the coating sintered at 500°C and 700°C has the best microstructure. To make the coating have higher hardness, the sintering temperature should be increased as much as possible at the allowable temperature of the substrate. The high-temperature erosion test shows that the erosion resistance of the coating is slightly lower than that of the substrate at room temperature and 400°C, but with the increase of temperature, the high-temperature erosion wear resistance is gradually enhanced, even exceeding the substrate, which is because the substrate is subjected to severe oxidation at high-temperatures, and its mechanical strength decreases with increasing temperature, while the coating is brittle at low temperatures, the erosion mechanism gradually becomes plastic as the temperature increases. The development of the shape erosion results in a much lower erosion wear at high-temperatures than the substrate.

Investigation of sea salt erosion effect on the asphalt-aggregate interfacial system

Under high-temperature and hygrothermal conditions, sea salt erosion can lead to asphalt-aggregate interfacial failure in porous asphalt concrete and cause aggregate raveling in coastal areas. Therefore, studying the damaging effect of sea salt erosion on an asphalt-aggregate interfacial system in a hygrothermal environment is necessary. First, the asphalt film thickness of a standard asphalt-aggregate specimen used in the simulation tests was determined according to the relationship between the tensile strength of the asphalt-aggregate specimen and the thickness of the asphalt film. The damaging effect of the salt solution was simulated by the 60°C high-temperature erosion test, and the solution type, solution concentration, and immersion duration were considered. The tensile strength and asphalt film-stripping ratio of the eroded specimens were analyzed, and the interfacial asphalt film dynamic equation σ2(t) and the stripping region interface dynamic equation σ2(t) were deduced. The results show that the 6 μm asphalt film thickness corresponds to the maximum tensile strength of the asphalt-aggregate specimen. With the increase of immersion duration, the tensile strength of asphalt-aggregate specimen decreased, and the asphalt film-stripping ratio of failure surface increased. In addition, the tensile strength of the interfacial asphalt film increased gradually due to the aging effect of the salt solution. The tensile strength of the stripping region’s interface did not descend to zero, but was obviously lower than the asphalt film. The 5% Na2SO4 solution has the highest damaging effect on the asphalt-aggregate interfacial system, followed by the 5% composite salt solution, 5% NaCl solution, water, and 10% NaCl solution..

Experimental and computational analysis for thermo-erosive stability assessment of ZrB2-SiC based multiphase composites

High temperature erosion tests were conducted on spark plasma sintered ZrB2-SiC based multiphase ceramic composites at 1073 K in thermo-erosive environment for 1200 s with a net energy deposition per unit area of 50.5 MJ/m2. The thermo-erosive mechanisms were qualitatively discussed using XRD and SEM-EDS analyses. Efforts were made to assess feasibility of identified reactions at the computed temperatures to support reaction mechanism for oxide formation in eroded region. Finite element (FE) analysis with high-quality structural elements was used to determine the spatial temperature and stress distribution in the eroded region. Taken together, the present study highlights the significance of combined approach of computational and experimental analysis in understanding the thermo-erosive-structural stability in applications where erosion can limit the performance of ceramic composites.

Microstructural evaluation and high-temperature erosion characteristics of high chromium cast irons

This present study investigated effect of chromium content on high temperature erosive wear characteristics of high chromium cast irons (Cr contain: 12%, 17%, 22% and 27% mass) for as cast specimens (AC) and heat treated specimens (QT), respectively. High temperature erosion test machine was used to investigate the erosive wear property of specimens at 1173 K. Alumina ball were used as particles at impact angles 30°, 60° and 90° and velocity is 100 m/s.As result, the addition of Cr is effective to increase the hardness of AC specimen, therefore, the erosion rate is also gradually reduced. On the other hand, for QT specimens, the erosion rate of 17Cr is almost same with 22–27Cr due to tempering process occurs that made M7C3 as dominant carbides in the matrix. The maximum difference hardness between AC with QT specimens is only 40 HV that difficult to consider its influence on the erosion rate. Therefore, the carbides of AC and QT were focused. From Cr/C ratio, it can be seen that there precipitated M3C and M7C3 into 12Cr and 17Cr, M7C3 into 22Cr and 27Cr. From the phase diagram, the microstructure is γ + M7C3 for each sample at 1173 K. Type and hardness of carbides are not changed at 1173 K for 22–27Cr AC and 22–27CrQT that resulted there is no significant difference in erosion rate after quenching compare to as cast. Therefore, the type of carbides is one of the main factors that can enhance the erosion resistance at 1173 K.

Effect of C Content on High Temperature Erosive Wear Characteristics of Fe-Based V Containing Multi-Component Cast Steel with Ni

Hot hardness and oxidation property of target material influences greatly on the erosion behavior at elevated temperature. The correlation between hot hardness and oxidation property of multi component white cast irons and its erosion resistance were investigated, and try to estimate the high temperature erosion behavior in the study. Nine kinds of multi component white cast iron and cast steel were used in this study. Specimen were machined into a flat plate with dimension of 50×50×10 mm. High temperature erosion test machine was used to investigate the erosive wear property of experimental materials at 1173K. Alumina grits (average diameter: 1.16 mm, hardness: 1250 HV1) which were used as impact particles were heated to 1073K and shoot on the heated specimen by hot air at the velocity of 100 m/s. The total particle loading was 2 kg. In order to clarify the correlation of hot hardness, oxidation property and the erosion resistance of specimens, hot hardness test was carried out specimens, to estimate erosion damage caused by solid particle. Hot hardness of specimens showed a value comparable to 200～250HV1. Result of erosion and oxidation tests, erosion rate and amount of oxidation of the specimen were suppressed by Ni addition. It suggested that the more amount of Ni contents, the lower the erosion rate and the less the amount of oxidation.

An innovative high temperature solid particulate erosion testing system

A new high temperature solid particulate erosion test system has been designed and built to improve the quality of high temperature erosion tests. The new test system is designed to carry out experiments at temperatures up to 900°C and particle velocities up to 300ms−1. A key feature is the use of commercial “air torch” technology to provide the necessary high air flow rates at elevated temperature giving the whole system a relatively small footprint. Measurements of erosion rate are revolutionised by two different forms of in-line measurement of wear to the sample. This new technology largely replaces the need for interrupting the test, cooling the test samples, and weighing at periodic intervals which can mean that a test with a total exposure of 30min to erosion by particles at high temperature can take most of a week. The two new technologies employed use a high precision balance to measure the in situ weight of the samples whilst they are still at test temperature, and the use of a custom designed blue laser triangulation system to measure the shape of the wear scars in situ and at temperature.The use of the new test system is illustrated by preliminary results of experiments from coated and uncoated Nimonic 80A.

High Temperature Erosion of Dense Refractory Castables for CFBC Boilers

The erosion resistance of dense refractory bricks or castables used in CFBC boilers is tested as per ASTM C 704. This method of testing determines the relative erosion of a refractory at room temperature only. Hence, solid particle erosion at elevated temperatures is desired in selecting the suitable refractory quality for boiler applications. The dense refractory materials for CFBC boilers are usually eroded at operating temperature (∼900°C) by hot circulating solids at high temperatures. In this work, low cement castable−45, low cement castable−80 and an 80% alumina-based plastic refractory castable, three varieties of dense refractory castables used in CFBC boilers, were selected for testing of erosion properties. The erosion tests were conducted at room temperature and boiler operating temperature of 900°C at three different angles of impingement (30°, 45° and 90°) using specially developed high temperature erosion test equipment following the ISO 16349 (2015) standard. The erosion loss result values (in cm3) were compared, and this comparison is useful in selection of suitable material for various erosion prone zones of the boiler.

Design and optimisation of the nozzle of an innovative high temperature solid particulate erosion testing system using finite element modelling

A new high temperature solid particulate erosion test system has been designed at the National Physical Laboratory to improve the quality of high temperature erosion tests. The new test system is designed to carry out experiments at temperatures up to 900°C and particle velocities up to 300 ms−1. This has been achieved through the careful design of the nozzle, balancing the gas flow, gas pressure and nozzle geometry to achieve the design goals. The nozzle design has been carried out using multi-physics Finite Element Modelling to analyse the gas flow and temperature.

Experimental studies on fly-ash erosion behavior of Ni-Cr based nanostructured thermal spray coating in boiler tubes

ABSTRACTErosion study was performed on the uncoated and coated SA210Gr-C boiler tube substrates. This study was performed in a view to reducing the scaling on boiler water-wall and super-heater tubes. In the present work, the High Velocity Oxygen Fuel (HVOF) coating process was used to deposit nanostructured and conventional coatings on the boiler tube substrates. Fly-ash produced after the combustion of coal in an Indian thermal power station was used as erodent. The erosion loss of coated and uncoated substrates was recorded at a regular interval of 30 minutes. The study was conducted at 30°, 60°, and 90° impingement angles and at two different operating temperatures (300°C, 550°C). Surface morphology of eroded samples was analyzed using macro and micro imaging techniques, and surface roughness was also recorded for the eroded samples. The phases present in the eroded substrates were indexed using the X-Ray diffraction (XRD) analysis. HRTEM images of nanostructured coated samples at 550°C with varying impingement angles were analyzed. The result reveals that the nanostructure in the coating was retained even after high-temperature erosion test. Comparative study was made with nanostructured and conventional coatings against the uncoated materials.

New features of solid particle erosion damage of control stage blades in supercritical steam turbine

Reducing solid particle erosion of blades is one of the most urgent problems for high-parameter steam turbine power generation technology. Based on the erosion rate model and particle rebound model of blade materials obtained through accelerated erosion test under high temperature, erosion characteristics of flaky particles in control stage of a typical supercritical steam turbine were systemically studied using three-dimensional numerical simulation method. The erosion mechanism of hard coatings on nozzle suction surface is first revealed, and erosion resistance of boride coating with large oxide particles is validated through high-temperature erosion test. Results show that serious erosion damage of boride coating on the latter half of nozzle suction surface is caused by the combined rebounded impingement of large particles between 1000 µm and 2000 µm after their initial impingement on the nozzle pressure surface and the leading edge of rotating blade. The average particle impingement velocity can reach up to 150–180 m/s, and the impingement angle is in the range of 18°–28°. High-temperature erosion test results show that boride coating will soon broken and fall off under the continuing impact of millimeter-sized particles, which confirms that hard coatings are difficult to resist the high-intensity impingement from these large particles. Therefore, separating particles before entering the nozzle chamber with the employment of an inertial separator should be the optimal choice for improving the erosion resistance of turbine. The results of this study enrich the types of blade erosion damage and provide a new idea for reducing erosion damage of control stage blades.

High erosion-oxidation performance of Fe-based Nb or V containing multi-component alloys with Co addition at 1173 K

High temperature erosion-oxidation behavior of Fe-based Nb or V containing multi-component alloys with Co addition is investigated at 1173K. High temperature erosion tests and oxidation tests are conducted to determine both erosion and oxidation behaviors. Oxide scales are detected on the surfaces with 5V–10Nb and 5V–10Co showing superior erosion-oxidation resistance at 1173K. The erosion rate is high in V-containing samples without Co due to the occurrence of vanadium oxide attack. Whilst, with increasing of Co content, the erosion rate is reduced, indicating the addition of Co is an effective counter-measure. In Nb-containing samples on the other hand, oxidation is successfully controlled by the formation of a composite oxide layer regardless of the presence of Co, thereby reducing the erosion losses.

Experimental investigation on erosion resistance of iron boride coatings for steam turbines at high temperatures

In this paper, high temperature erosion tests are performed on four typical anti-erosion coatings for high-parameter steam turbine blades using pneumatic accelerated erosion method to simulate the actual erosion environment in power units. With the employment of scanning electron microscope, energy-dispersive X-ray spectroscopy, glancing-angle X-ray diffraction, and Vickers indentation testing techniques, detailed microscopic analysis of samples is conducted to reveal the underlying causes affecting the anti-erosion performance of coatings. Results show that, under the solid particle erosion at high temperature, boride coatings with more compact structure and higher hardness have stronger anti-erosion ability, whose erosion rate is only 30–50% that of HVOF Cr3C2 coatings under the same erosion condition. Boride coatings composed of duplex phase (FeB and Fe2B) have lower anti-erosion damage capability than that of boride coatings composed of single Fe2B phase. Under high-speed large incidence angle impingement, the surface layer of FeB cracks easily and rapidly propagates to the subsurface layer Fe2B phase under the sustained impingement from particles, resulting in the flaking off and failure of coatings. Single Fe2B phase boride coatings have smaller hardness gradient in the depth direction and higher fracture toughness than boride coatings composed of duplex phase, so that exhibit more stable excellent erosion resistance under different erosion parameters. Therefore, single Fe2B phase boride coatings should be used as the preferred wear resistant coating for turbine blades solid particle erosion problem.

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

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

Erosion rate testing at high temperature for turbomachinery use

A high temperature erosion test facility was designed by Tabakoff and Wakeman (Test facility for material erosion at high temperature, ASTM Special Publication, 664 (1979) 123–135) to provide erosion data in the range of operating temperatures experienced in compressors and turbines. In addition to the high temperatures, the facility properly simulates all the erosion parameters which were determined to be important from the aerodynamics point of view. These parameters include particle velocity, angle of impact, particle size, particle concentration and sample size. For a better understanding of the use of this tunnel and to obtain good results, definitions of the parameters used in the wind tunnel testings and test procedures are presented: for example, an experimental study which was conducted to investigate the erosion behavior of titanium carbide coating exposed to fly ash and chromite particles. The chemical vapor deposition technique (CVD) was used to apply a ceramic coating on nickel and cobalt based superalloys (M246 and X40). The test specimens were exposed to particle laden flow at velocities of 305 and 366 m s −1 and temperatures of 550°C and 815°C.

Wear of Alloy Steels by Impact of Powder at High Temperature.

In our previous study, as a result of the air-blast erosion tests at room temperature, the wear of materials by impact of powder could be estimated from the impinging conditions and the properties of materials and particles. In this study, some alloy steels were tested using the high-temperature erosion test equipment, and the effects of the wear factors on the wear rates were investigated. At a relatively low temperature (300°C), using the predicting method reported in our previous study, the wear rates calculated from the hardness of the materials and the particles at room temperature were close to the experimental results. At a higher temperature (700°C), the wear rates of the materials were increased because the materials were more ductile and softer. The wear rates calculated from the hardness at high temperature, using the same predicting method, were relatively close to the experimental results when the hardness of the materials at high temperature, data which are not obtained easily, were estimated on the assumption that the hardness is proportional to the tensile strength.