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Sliding wear is a common phenomenon in the iron ore handling industry. Large-scale handling of iron ore bulk-solids causes a high amount of volume loss from the surfaces of bulk-solids-handling equipment. Predicting the sliding wear volume from equipment surfaces is beneficial for efficient maintenance of worn equipment. Recently, the discrete element method (DEM) simulations have been utilised to predict the wear by bulk-solids. However, the sensitivity of wear prediction subjected to DEM parameters has not been systemically investigated at single particle level. To ensure the wear predictions by DEM are accurate and stable, this study aims to conduct the sensitivity analysis at the single particle level.

In this research, pin-on-disc wear tests are modelled to predict the sliding wear by individual iron ore particles. The Hertz–Mindlin (no slip) contact model is implemented to simulate interactions between particle (pin) and geometry (disc). To quantify the wear from geometry surface, a sliding wear equation derived from Archard’s wear model is adopted in the DEM simulations. The accuracy of the pin-on-disc wear test simulation is assessed by comparing the predicted wear volume with that of the theoretical calculation. The stability is evaluated by repetitive tests of a reference case. At the steady-state wear, the sensitivity analysis is done by predicting sliding wear volumes using the parameter values determined by iron ore-handling conditions. This research is carried out using the software EDEM^® 2.7.1.

Numerical errors occur when a particle passes a joint side of geometry meshes. However, this influence is negligible compared to total wear volume of a wear revolution. A reference case study demonstrates that accurate and stable results of sliding wear volume can be achieved. For the sliding wear at steady state, increasing particle density or radius causes more wear, whereas, by contrast, particle Poisson’s ratio, particle shear modulus, geometry mesh size, rotating speed, coefficient of restitution and time step have no impact on wear volume. As expected, increasing indentation force results in a proportional increase. For maintaining wear characteristic and reducing simulation time, the geometry mesh size is recommended. To further reduce simulation time, it is inappropriate using lower particle shear modulus. However, the maximum time step can be increased to 187% T_R without compromising simulation accuracy.

The applied coefficient of sliding wear is determined based on theoretical and experimental studies of a spherical head of iron ore particle. To predict realistic volume loss in the iron ore-handling industry, this coefficient should be experimentally determined by taking into account the non-spherical shapes of iron ore particles.

The effects of DEM parameters on sliding wear are revealed, enabling the selections of adequate values to predict sliding wear in the iron ore-handling industry.

The accuracy and stability to predict sliding wear by using EDEM^® 2.7.1 are verified. Besides, this research accelerates the calibration of sliding wear prediction by DEM.

Presents development and characterisation of a new metal/polymer composite material for use in fused deposition modelling (FDM) rapid prototyping process with the aim of application to direct rapid tooling. The work represents a major development in reducing the cost and time in rapid tooling.

The material consists of iron particles in a nylon type matrix. The detailed formulation and characterisation of the thermal properties of the various combinations of the new composites are investigated experimentally. Results are compared with other metal/polymer composites used in rapid tooling.

The feedstock filaments of this composite have been produced and used successfully in the unmodified FDM system for direct rapid tooling of injection moulding inserts. Thermal properties are found to be acceptable for rapid tooling applications for injection moulding.

Introduces an entirely new metal based composite material for direct rapid tooling application using FDM RP system with desired thermal properties and characteristics. This will reduce the cost and time of manufacturing tooling inserts and dies for injection moulding.

The purpose of this paper is to help understand the mathematical model of inductive sensor and to improve the sensitivity of nonferrous metal particle detection.

The expression of impedance change is established, while the distribution regularities of the magnetic field inside and outside the metal particle are obtained based on the Maxwell equations in complex forms, the analytic solution of the electromagnetic field is obtained and the experiment validation is implemented.

The expression of impedance and the analytic solution of the electromagnetic field are obtained. It is shown that the inductance change is more obvious than resistance change for the iron particles, but for copper particles, resistance change is more obvious and the resistance change increases with the frequency. In this work, copper particles (size: 20 µm) are detected at 2 MHz excitation frequency, and the imaginary part of impedance changes without adding any device, which is provided with a prominent guideline for detection of nonferrous particles of size less than 100 µm.

The expression of impedance change is established, the analytic solution of the electromagnetic field is obtained and copper particles (size: 20 µm) are detected at 2 MHz excitation frequency, and the imaginary part of impedance change without adding any device, which is provided with a prominent guideline for detection of nonferrous particles of size less than 100 µm.

The purpose of this paper is to study the effect of blending time, SiC content and fill ratio on the homogeneity of iron‐silicon carbide powder mixture, blended in double‐cone blender; to evaluate density, microstructure and micro hardness of laser sintered iron and iron‐SiC specimens; and study the feasibility of building a complex iron‐SiC metal matrix composite (MMC) part by direct metal laser sintering (DMLS) process.

The morphology and particle size of iron and silicon carbide powders were evaluated. Nickel coating was carried out on silicon carbide particles. Blending of iron‐SiC powders were carried out in two phases in a double‐cone blending equipment. In the first phase, three tests were conducted with fill ratios (ratio of volume of conical blender to volume of powder mixture) of 1.68, 3.39, and 6.8 percent while iron‐SiC weight ratio was kept constant at 97:3. In the second phase, four tests were conducted with iron‐SiC weight ratios of 99:1, 98:2, 97:3, and 95:5 while keeping a constant fill ratio of 1.68 percent. In both the phases, blending was carried out for duration of 43 minutes. Homogeneity of the powder mixture was evaluated at different intervals of time by adopting sampling process. Sintering was carried out on iron and iron‐SiC powder mixture using DMLS machine at laser speed of 50, 75, 100, and 125 mm/s. Microstructure, density and micro hardness studies were carried out on the sintered specimens. A 3D model of a part with complex geometry was modeled using Unigraphics CAD/CAM software and prototype part was built by DMLS technology using the blended iron‐2 weight percent SiC powder.

A reduction in blending time was observed with increase in SiC content and decrease in fill ratio. Microstructure and micro hardness tests conducted on laser sintered iron‐silicon carbide specimens, reveal the homogeneity of blended powder. The density of the iron‐SiC composites sintered at a laser speed of 50 and 75 mm/s, decreased with increase in SiC content. Further, an increase in the micro hardness of iron‐SiC composites was observed with increase in SiC content and decrease in laser speed. Complex functional part was built by DMLS technology with out any supports.

The experiments were conducted with standard blending equipment in which the speed is limited to 48 revolutions per minute only.

Meager information is available on blending of powders for producing MMCs by laser sintering process. The work presented in this paper will be a guideline for researchers to carry out further work in blending of powders for producing MMCs by rapid prototyping process.

This study aims to perform the surface treatment of synthetic α-Fe₂O₃ red iron oxide pigment with hydrolysate 3-aminopropyl silane (A) and colloidal silica (CS) and investigate the effects of surface-treated pigment on the styrene acrylic (SA) emulsion and polyurethane (PU) dispersion.

For this purpose, firstly red iron oxide particles were modified with A and CS separately in an aqueous medium. After isolation of the modified iron oxide were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). Moreover, the degree of the dispersion stability of the modified pigment in coatings with SA emulsion and PU dispersion was investigated by using an oscillation rheometer. Loss (G''), storage (G') modulus, loss factor [tan(δ)] and yield stress (τ⁰) values were determined by performing amplitude and frequency sweep tests.

The τ⁰ in SA coatings decreases with the amount of used A and increases with the amount of used CS. The τ⁰ decreases as the amount of used A and CS in PU coatings increases. The use of CS on red iron oxide pigments causes storage modulus to increase in SA coatings at low angular frequencies, while it causes a decrease in PU coatings.

To the best of the authors’ knowledge, for the first time, the suspended state of the iron oxide hybrid pigment formed with CS in the coating was investigated rheologically in this study.

This paper aims to study the influence of the different parameters of magnetorheological polishing fluids (MRP fluids) on the surface roughness and material removal rate (MRR) of the workpiece surface in the reciprocating magnetorheological polishing (RMRP) process.

A series of single-factor experiments are performed to evaluate the influence of the concentration of magnetic particles, concentration of abrasive particles and size of abrasive particles on surface processing effects by using the RMRP method. Moreover, the yield stress and viscosity of MRP fluids are studied based on the Bingham plastic model by varying the MRP fluids parameters.

A reasonable parameter of MRP fluids is crucial to the surface roughness and MRR of the workpiece surface, and the optimized parameters are obtained by the single-factor experiments of RMRP. The results are when the concentration of carbonyl iron particles is 40 Vol.%, the concentration of CeO₂ is 5 Vol.% and the size of CeO₂ is 2.5 µm in the MRP fluids, the surface roughness of the workpiece remarkably decreases to 28 nm from the initial 332 nm and the MRR of the workpiece increases to 0.118 mg/min.

In this study, the single-factor experiments for the different parameters of MRP fluids are studied to polish K9 glass by using the RMRP device, and the yield stress and viscosity of MRP fluids are investigated by rheological experiments, which provides reference for a reasonable selection of the MRP fluids parameter in RMRP process.

The purpose of this paper is to determine whether the altitude at which construction equipment operates affects or contributes to increased engine wear.

The study includes the evaluation of two John Deere PowerTech Plus 6,068 Tier 3 diesel engines, the utilization of OSA3 oil analysis laboratory equipment to analyze oil samples, the employment of standard sampling scope and methods, and the analysis of key Engine Control Unit (ECU) data points (machine utilization, Diagnostic Trouble Codes (DTCs) and engine sensor data).

At 250 h of engine oil use, the engine operating at 3,657 meters above sea level (MASL) had considerably more wear than the engine operating at 416 MASL. The leading and earliest indicator of engine wear was a high level of iron particles in the engine oil, reaching abnormal levels at 218 h. The following engine oil contaminants were more prevalent in the engine operating at the higher altitude: potassium, glycol, water and soot. Furthermore, the engine operating at higher altitude also presented abnormal and critical levels of oil viscosity, Total Base Number and oxidation. When comparing the oil sample analysis with the engine ECU data, it was determined that engine idling is a contributor for soot accumulation in the engine operating at the higher altitude. The most prevalent DTCs were water in fuel, extreme low coolant levels and extreme high exhaust manifold temperature. The ECU operating data demonstrated that the higher altitude environment caused the engine to miss-fire and rail pressure was irregular.

Many of the mining operations and construction projects are accomplished at mid to high altitudes. This research provides a comparison of how construction equipment engines are affected by this type of environment (i.e. higher altitudes, cooler temperatures and lower atmospheric pressure). Consequently, service engineers can implement maintenance strategies to minimize internal engine wear for equipment operating at higher altitudes.

The main contribution of this paper will help construction equipment end-users, maintenance engineers and manufacturers to implement mitigation strategies to improve engine durability for countries with operating conditions similar to those described in this research.

Ball bearings in gas turbine have played a critical role in supporting heavy radial loads but with higher failure rates and repair costs. Therefore, the purpose of this study is to introduce and study a method for their failure analysis with an actual industrial example to guarantee operation reliability and safety.

Spectrometric oil analysis was used as an early abnormal wear indicator, based on which emergent in-use oil replacement was carried out to reduce the wear rate. However, with wear deterioration, further wear failure investigation was conducted by LaserNet Fines and ferrography to detect the imminent wear failure. Finally, with the assistance of elemental analysis of the typical wear particles, the root cause and worn components were determined by scanning electronic microscope and energy-dispersive X-ray spectroscopy.

The results have shown that an extraneous source led to wear failure, which later caused overheat between the outer bearing ring and ball. It is in accordance with visual inspection of the disassembled engine.

This method has specified the occasion under which the suitable measurement can be taken. It can achieve the rapid wear condition assessment allowing for root cause and worn parts identification. In addition, wear rate reduction by change of oil can be efficient for most of the time to avoid premature disassemble, especially with the possibility of contamination. It has provided experience to address similar industry-level practical wear failure analysis problems.

One of the problems in the production of narrow hot‐rolled mild steel strip is the formation, at the edges of the strip, of scale that can be extremely resistant to pickling; This extreme resistance to pickling of ‘hard edge scale’ sometimes requires repickling of a considerable percentage of coils with consequent loss of production and deterioration of surface finish. The paper considers in detail the correlation between the microstructure of scale on the strip and its pickling behaviour. It is shown that certain characteristics of the microstructure, peculiar to ‘hard edge scale’, i.e. increased thickness, the presence of a primary magnetite layer, greater degree of wüstite transformation and the nature and presence of haematite, can be suppressed to a greater or lesser degree by variations in the cooling cycle. It is considered that no single one of these structural differences between hard edge scale and that which is removed readily from the centre of the strip would, by itself, interfere with pickling, but when these characteristics occur together repickling is made necessary. The above observations and conclusions are supported by results obtained from pickling tests carried out in the laboratory on samples taken from a wide range of coils.

THE demands of war have created an increasing necessity for very strict inspection of component parts of aero and other internal combustion engines ; more particularly with the former, as more and more power is demanded from them.