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Erosion is an unavoidable phenomenon in the pipelines transporting bulk solids in both hydraulic and pneumatic conveying modes. Erosion wear depends on a number of factors like hardness of the material, size and shape of the solid particles, solid concentration, velocity of particles, impact angle of solids on the target material surface etc. Several investigators have made systematic studies to establish...
A novel plasma-spray process, featuring simultaneous injections of dry powders and multiple liquid streams, was employed to produce composite coatings where sub-micrometric particles of Al2O3 and hexagonal BN (h-BN) are dispersed within a NiCrAlY metal matrix. Various coatings, containing up to ≈10wt% Al2O3 and ≈9wt% h-BN, were obtained. A co-deposition effect was noted whereby a higher h-BN feed...
Autumn leaves often cause low adhesion problems for train operations, leading to station overruns and signals passed at danger (SPADS). The aim of this paper was to review operational data and research methods to assess the current understanding of the problem and formulate hypotheses for the causes. Incident analysis showed the relatively high possibility of incidents between the hours of 05:00–10:00...
Joining of high strength materials using friction stir welding (FSW) is difficult due to severe tool wear and change in the shape/size of the tool. However, quantitative understanding of tool wear during FSW of high melting point metallic materials is very limited. Here we present quantitative wear analysis of H13 steel tool during FSW of CuCrZr alloy. Higher amount of total tool wear is observed...
The objective of this paper is to investigate the influence of fine particle bombardment (FPB) on the scuffing behavior of ductile cast iron. Ductile cast iron samples were processed by FPB treatment, in which three injection air pressures (0.2MPa, 0.4MPa and 0.6MPa) were used for given particle flux (8–10g/s), treatment time (15s), nozzle diameter (9mm) and standoff distance (100mm). Surface morphology,...
Sediment particles flowing through the turbine components erode the surface in interaction. Erosive wear of hydro turbine components generally depends on different parameters such as concentration, size and shape of the sediments particle, velocity of flow, properties of the base material of the turbine components and operating hours of the turbine. Tarbela Dam Hydel Project (TDHP) located in the...
Enhancing the abrasive wear resistance (WR) of polymer composites is an extremely difficult task since the particles or fibers are easily dug out or broken leading to a deterioration of their wear resistance. Exploration of hard particles in the right amount, size and compatibility with the matrix may lead to the reduction in micro-cutting and micro-ploughing of the matrix. Very few successful efforts...
Two running-in processes, i.e., polishing a diamond-like carbon (DLC) coated disk and pre-sliding in ambient air, were suggested as a delamination suppression method for self-mating DLC coatings in water, and the effects of these methods were verified using a ball-on-disk tribometer. An a-C:H-type DLC coating was deposited on SUJ2 bearing steel balls and disks using plasma chemical vapor deposition...
The mechanisms of cracking in multi-layered composite nano-structured coatings deposited through the use of the technologies of filtered cathodicvacuum arc deposition(FCVAD) (coatingsZr-ZrN-(ZrCrAl)N, Cr-CrN-(TiCrAl)N, Zr-ZrN -(ZrNbTiAl))and lateral rotating cathodes (coating Ti-TiAlN-TiAlN) are explored herein.The formed coatings are characterised by parameters such as hardness, adhesion strength...
The scratch resistance of thin ZnO films deposited on a polyimide interlayer is characterized experimentally and simulated using a 3D finite element model. Nanoscratch tests combined with scanning electron microscopy observation to analyze the failure mechanisms in the brittle hard films are performed. The thickness of the polymer interlayer is shown to play a major role in controlling the scratch...
The stick–slip behavior of polymers sliding on a cast-iron counter surface was investigated using four different polymers: polymethylmethacrylate (PMMA), polycarbonate (PC), polyvinyl chloride (PVC), and polytetrafluoroethylene (PTFE). Particular attention was given to the correlation between the stick–slip pattern and the material properties such as the tensile strength, modulus, and surface energy...
To investigate the specific matching characteristics of Tunnel Boring Machine (TBM) cutter ring properties and rock, matching friction tests for six kinds of TBM cutter ring specimens with different properties and two kinds of typical TBM rock samples were performed on a bespoke TBM cutter performance test bench. The results indicate that the matching characteristics of the TBM cutter ring properties...
This paper presents the results of an experimental campaign based on lubricated rolling-sliding tests carried out in the disc on disc configuration for different material solutions.The aim is to find alternative solutions to the couple bronze-quenched and tempered steel, recognised as standard solution for worm gearing. A steel-steel coupling was considered, providing different surface modifications...
The effects of chromium additions on three-body abrasive wear behavior of Fe-3.0wt% B alloy have been systematically investigated using a moving wedge type of apparatus and two types of abrasives (SiC and SiO2 grains). Features of both the worn surface and subsurface have been discussed with regard to the respective wear rates. As chromium increased, the wear rate of Fe-3.0wt% B alloy first decreases...
Solid particle erosion plays a critical role in the design and reliability of equipment employed in the oil and gas industry. Significant erosion occurs due to solid particle loading, especially in applications involving sand production. Low particle loading in drilling fluids (<10%) is also a source of erosion inside downhole tools and in rig equipment at the surface. Accurate prediction of erosion...
The objective of the paper is the quantification of effects of erodent flow kinetic energy and exposure time on the erosion of cement-based composites with high-speed hydro-abrasive jets. The erodent flow kinetic energy is varied due to changes in erodent velocity, traverse rate and erodent particle mass-flow rate. For a given traverse rate, the relationship between volumetric erosion rate and erodent...
The aim of this work was to study the influence of a hard chrome (HC) intermediate layer on the reciprocating abrasive wear behaviour of Mo-based coatings deposited by DC magnetron sputtering on AISI 316 stainless steel. The two-body abrasive wear characteristics of sputtered MoN, MoC and MoCN coatings on AISI 316 stainless steel with an electroplated HC layer were systematically evaluated using test...
Powder Bed Fusion (PBF) is a group of powder-bed based layered Additive Manufacturing (AM) techniques for direct fabrication of metal and metal alloys. Despite its advancements, the surface quality of as-built PBF components remains unsatisfactory. In this paper, a new post-process finishing technique, based on ultrasonic cavitation effects in a solid-liquid mixture, is introduced for PBF-built components...
The time for which each contacting body is exposed to a tribological contact affects its interface temperature, third-body and tribofilm formation, and, as a result, the overall tribological behaviour, which may be particularly relevant with very dissimilar material pairs. This work focuses on the tribological properties of unreinforced polyamide (PA6) in self-mated contacts or against steel (SS)...
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