Cause Of Wear Research Articles

Особливості зносу пар тертя канат-блок і канат-барабан за умов роботи підйомно-тягових пристроїв

The features of wear of rope-block and rope-drum friction pairs of lifting and traction devices operating in the conditions of a hot manufactory of the metallurgical plant and also the mining and beneficiation plant were studied. It is shown that the causes of wear of the elements of the rope-block and rope-drum friction pairs are the interaction in their contact zones, which occurs in the surface layers under the influence of high contact stresses, friction, cyclic loads, abrasive particles, active atmospheric and industrial environments. It was found that these actions lead to irreversible processes of accumulation of stresses and plastic shifts, which have a periodic and heterogeneous character. It is shown that the strength of the lifting or traction rope is determined by the degree of wear of the wires, primarily those in contact with the block and the drum. The structural changes in the surface layers of the wires and the mechanisms of the formation of wear particles were analyzed, which confirm the heterogeneous nature of the wear of the wires in the strands of the rope. Areas of abrasive wear were also observed on the worn surface of the wires, where under the action of solid foreign particles of contamination with sharp corners falling between the wires, the surface of the wires was undercut. It is shown that the presence of non-metallic inclusions leads to the formation of wear particles and fatigue cracks. It was established that the wear of friction pairs of rope-block and rope-drum of hoisting and traction devices has a fatigue-corrosive nature, and the main mechanism of the formation of wear particles is the development of plastic shifts in the surface layers of friction pairs and their separation by plastic exfoliation and abrasive and corrosive destruction. The shape of the wear particles depends on the type of material and the conditions of their formation. It is proposed to take measures regarding structural approaches to friction pairs, taking into account their working conditions, in order to reduce contact stresses and increase their wear resistance, reliability and durability.

Investigation of piston ring wear engines by the mathematical statistics method

Improving the reliability and durability of internal combustion engines makes it possible to increase productivity and reduce the cost of operation. The study of nature and magnitude of piston rings wear is relevant and represents a scientific novelty. During the operation of internal combustion engines, it is almost impossible to determine the influence of various factors on the wear rate and the resource of piston rings. One of the most accurate ways to study the wear intensity and the service life values of internal combustion engines piston rings during operation is the statistical method. The method of mathematical statistics allows us to study the nature and magnitude of individual parts wear with a sufficient degree of accuracy, to determine the main causes of wear, to outline ways of increasing the parts wear resistance, to establish durability criteria, to reasonably assign standard service life of parts and plan the parts need for any period with a given probability, with climatic conditions being taking into account. The article presents the collected statistical material on the internal combustion engines piston rings wear of construction and road vehicles operated at construction sites of Rostov region. It has been processed according to the normal Gauss law and data on the wear and service life of piston rings are obtained. The obtained experimental data on the wear of piston rings in height are reliable to the distribution law and can be used to determine the intensity of engines piston rings wear at repair enterprises.

High-temperature oxidation and erosion of HVOF sprayed NiCrSiB/Al2O3 and NiCrSiB/WC[sbnd]Co coatings

Material deterioration due to erosion and oxidation in high-temperature environments is a major cause of wear in power plants, aircraft engines and petrochemical industries. NiCrSiB based surface coatings using thermal spray techniques such as High-Velocity Oxy-Fuel (HVOF) offer a cost-effective route to improve the tribological properties for a range of substrate materials. The study investigates the high-temperature oxidation and erosion resistance of HVOF coated NiCrSiB reinforced with Al2O3 and WCCo on SS304 stainless steel substrate. The oxidation kinetics and erosion responses of the coatings at 750 °C were evaluated for a period of 160 hrs and the coating microstructure, morphology and chemical compositions characterised. A total of three coating compositions were studied namely: NiCrSiB/Al2O3, NiCrSiB/n-Al2O3 and NiCrSiB/WCCo where the results indicate a superior oxidation and erosion resistance in all cases in comparison to uncoated SS304. However, it was found that the NiCrSiB reinforced with micro-structured Al2O3 outperformed all the other coatings in terms of oxidation resistance. When it comes to erosion resistance, NiCrSiB/WCCo was found to demonstrate the highest performance.

Investigation of Valve Tip End Wear Mechanism of a Four-Cylinder Automotive Engine Under High-Speed Application

This work investigates the causes of wear occurring at the engine valve tip end after 400 hours of engine operation. Fatigue wear was observed on the valve tip at the product development stage of the engine, which is going to be used in an automotive vehicle. Valves were assembled on a gasoline/CNG fuel-based four-cylinder IC engine. In this engine, tip end wear was prominent during high-speed testing conditions as compared to other types of engine tests. The chemical composition of worn surfaces was verified by spectroscopy. The microstructures, grain sizes and surface roughness were determined by optical microscopy and surface roughness tester. To evaluate the wear mechanism, valve tip end worn surfaces were analyzed using Scanning electron microscopy. The SEM analysis indicates the initiation of micropits and subsequent propagation of the fatigue wear during engine operating conditions. The residual stresses were measured at valve tip end surfaces and subsurfaces using X-ray diffraction techniques. Several investigations employing multiple techniques were carried out to identify the root cause of failure while comparing results against those of untested valves. Parameters that can affect valve tip end properties were identified in the study and countermeasures provided, and that lead to successful completion of the testing with the same operating condition.

Visualization of wheel-rail contact area of running vehicle using film sensor

Proper evaluation of the wheel-rail contact is necessary to understand the dynamics of railway vehicles and the causes of wear and damage to components such as wheels and rails. Numerical methods are often used to evaluate the dynamic contact condition between the wheel and rail; however, there are few promising methods for experimental evaluation. It is important to develop a measurement method because the wheel-rail contact is easily changed owing to vehicle-track dynamic interactions. In this study, we used a film-based pressure sensor equipped with force-sensitive resistors to measure the contact area between the wheel and rail during vehicle operation. Using the film-based pressure sensor, we evaluated the geometry of the contact area and position. The validity of the measured contact position is evaluated by comparing it with the contact position based on the cross-sectional profiles of the wheel and rail and the wheelset displacement during a vehicle running.

Influence of water absorption on friction, wear and abrasion resistance of PA6-hBN composites

Investigations on the tribological properties, i.e., abrasion resistance, friction coefficient, and wear of water conditioned polyamide6/hexagonal boron nitride composites were carried out in this research. Polyamide6 and polyamide6/hexagonal boron nitride composites were fabricated with the help of a twin-screw extruder and injection moulding machine. Fabricated materials were water immersed for 15 days to analyse the effect of water absorption on the tribological properties of materials. Tribological tests were carried out on a pin-on-disc tribometer, and abrasion resistance tests were performed on a TABER abrader. The SEM analysis was carried out to analyse the wear tracks of water conditioned composites. Testing on TABER abrader revealed the loss in abrasive resistance of composite materials, while tribological testing of composites with steel as the other mating and rubbing surface revealed improvements in COF and wear after water absorption. The SEM images revealed less depth of wear in water conditioned materials compared to dry ones. The causes of wear were found as the stick and slip, i.e., adhesive wear in which material tends to stick during matting with steel disc, and due to the continuous movement, it slips. Water absorption was found supportive in the formation of smooth lubricating transfer film on a steel disc. Bonding between the polyamide matrix and water molecules plus the formation of boric oxide & orthoboric acid were found advantages in decreasing the friction coefficient and wear of water conditioned composites.

Performance evaluation of esters and graphene nanoparticles as an additives on the rheological and lubrication properties of water-based drilling mud

In the practice of drilling horizontal, directional, and unstable well profiles, the friction produced by bit balling, wellbore instability, cavings, and dog-legs resulted in excessive torque and drag. The friction along with high torque and drag, which results from the drill string, casing, and wellbore contact, leads to pipe stucks, overpulls during tripping-outs, and even closure of the oil and gas well. Heat generated from metal contact between casing and drill string is the cause of wear of drill string and casing. Oil-based drilling fluids are identified to produce minimum friction and torque than that of water-based drilling fluid/mud (WBM). However, the use of oil-based drilling fluids is becoming obsolete due to stringent environmental regulations. Therefore, it is critical to identify and design a water-based drilling mud with lubricant additives that are environmentally friendly, cost-effective, and give better lubrication similar to oil-based and synthetic-based drilling fluid. The objective of this study is to investigate the effect of two additives PC60 (the product of the reaction of glycerol ​+ ​tall oil fatty acid) and graphene nanoparticles on the rheological and lubrication properties of water-based drilling fluid. All together total 14 drilling fluid samples have been prepared for the detailed analysis. Extensive experimental work has been done to study the effect of lubricant additives (PC60 and graphene nanoparticles) on the rheology and lubrication of various WBMs with different additive concentrations (1, 2, and 3% by volume) at 30, 60, and 90 ​°C. All samples were investigated for their rheology, viscoelastic behavior, and lubrication properties before and after hot rolling. The experimental data generated in this work have been successfully utilized to find various fitting parameter for the Bingham plastic rheological model, followed by a discussion on foaming tendency of the samples and effect of pH on the rheological stability of drilling fluid. Subsequently, a relationship between the coefficient of friction (in the presence of different lubricant additives in the mud) and rheological properties (plastic viscosity and yield point) of different drilling fluid samples have been proposed. • Rheological/lubrication properties of water-based drilling muds (WBMs) investigated. • The effect of two additives ester and graphene nanoparticles on WBM studied. • Ester-based WBMs shown better rheological performance/stability after hot rolling. • A relationship between coefficient of friction and rheological properties proposed. • Ester-based WBMs exhibit more foaming tendency than nano-graphene-based WBMs.

Підвищення довговічності турбокомпресора в внаслідок ремонтного впливу

A turbocharger is a unit of modern internal combustion engines designed to boost it. Since a drive of the turbocharger is most often carried out from the energy of the exhaust gases, the conditions of its operation can not be called favorable: the temperature of the exhaust gases sometimes reaches 7000C, high chemical activity of the exhaust gases, high speed of rotation of the turbine. The consequence of difficult operating conditions is the wear of its elements. One of the main causes of wear of the active elements of the turbocharger is abrasive wear. Various methods of restoration and strengthening can be used to restore machine parts. However, not all methods can provide the necessary resource for the restoration and strengthening of parts working in abrasive and corrosive environments. One of the modern directions of increasing the wear resistance and other properties of reducing coatings is the use of composite materials. This article presents the results of research on the development of a new method for restoring and strengthening parts with composite materials based on the use of chemical vapor deposition of metals CVD - method (Chemicikal Vapor Deposition) by decomposition of organometallic compounds. It is shown that the developed composite material obtained by the CVD-method of decomposition of organometallic compounds provides an increase in wear resistance of at least 2.0...2.2 times in comparison with new parts composite material. Vapor-phase deposition of metals, Chemicikal Vapor Deposition-method, decomposition of organometallic compounds.

An experimental and theoretical study of the abrasion performance of digital light processing parts

Generally, interactions at surface asperities are the cause of wear. Two-Thirds of wear in industry occurs because of the abrasive or adhesive mechanisms. This research presents an analytical model for abrasion of additive manufactured Digital Light Processing products using pin-on-disk method. Particularly, the relationship between abrasion volume, normal load, and surface asperities’ angle is investigated. To verify the proposed mathematical model, the results of this model are verified with the practical experiments. Results show that the most influential parameters on abrasion rate are normal load and surface’s normal angle. Abrasion value increases linearly with increasing normal load. The maximum abrasion value occurs when the surface’s normal angle during fabrication is 45°. After the asperities are worn the abrasion volume is the same for all specimens with different surface’s normal angle. Though layer thickness does not directly affect the wear rate, but surface roughness tests show that layer thickness has a great impact on the quality of the abraded surface. When the thickness of the layers is high, the abraded surface has deeper valleys, and thus has a more negative skewness. This paper presents an original approach in abrasion behavior improvement of DLP parts which no research has been done on it so far; thus, bringing the AM one step closer to maturity.

ДЕЯКІ АСПЕКТИ ПІДВИЩЕННЯ ЕНЕРГОЕФЕКТИВНОСТІ РОБОТИ ШАХТНИХ ВІДЦЕНТРОВИХ НАСОСІВ

Mine drainage systems, which are used at the main drainage of mining enterprises, have a drive capacity of up to 1600kW. To reduce non-productive energy losses, as well as for the continuous operation of the mining company, mine pumps must be energy efficient and reliable. Analysis of downtime of drainage systems shows that the weak point is the unloading device. This fact can lead not only to the failure of the pumping unit, but also to possible prolonged downtime of the mine. The main disadvantage of the existing disk unloading devices of mine pumps is their low reliability and low service life, due to the rapid wear of the components of the unloading unit. The most vulnerable elements of the unloading device are the unloading rings. The need for frequent replacement and adjustment of the elements of the discharge unit is associated with disassembly and assembly of the pump directly in the pump chamber. Such actions require significant costs of unproductive manual labor of service personnel, and rapid wear of parts of the unloading device necessitates their constant replenishment. Malfunctions in the unloading device can cause significant pump failures. To increase the reliability and energy efficiency of mine drainage systems, the method of control of the unloading device was used. During the experimental studies it was found that cavitation phenomena during the operation of pumping units are absent and, accordingly, can not be the cause of wear of the elements of the unloading unit. When the pumps are operating in steady state, the displacement of the rotors was monitored for 3-4 hours on each pump unit. After data processing, it was obtained that the wear of the surface of the unloading rings occurs at a rate of 0.05-0.15mm in one hour. To determine the wear of the rings of unloading during start-up - stop of the pump, at first the indicators of measuring devices at the established mode of operation of the pump unit were fixed. Then the pump was turned off and on again. After starting the pump unit, we made sure that the operating mode of the unloading device did not change and compared the readings of the shaft position indicator before stopping and after starting the pump. From the measurements made it followed that stopping and starting the pump does not lead to noticeable wear of the unloading device. Therefore, it can be assumed that mainly the wear of the discharge rings occurs during the steady operation of the pump unit.

Possíveis pontos de contaminação do óleo lubrificante por sílica, em motores diesel

O alto custo de manutenção e despesas com lubrificantes são citados como desvantagens da mecanização agrícola. O setor de manutenção de frota é responsável por grande parte dos custos nas propriedades agroindustriais e toda inovação empregada na redução destes custos pode impactar diretamente no preço final do produto. A análise laboratorial do óleo lubrificante é uma das principais ferramentas de manutenção para verificação de anormalidades no motor diesel e torna possível o monitoramento das condições químicas e físicas do óleo por meio de análises que apontam a presença de contaminação por água, partículas ferrosas e contaminantes externos como a Sílica, que pode ser proveniente da poeira, e é uma das principais fontes de contaminação do óleo lubrificante, sendo a causa mais comum de desgaste. Diante deste contexto, o objetivo do presente artigo é indicar os possíveis pontos de contaminação do óleo lubrificante do motor diesel por Sílica e propor um check list que possa ser utilizado numa inspeção visual detalhada, a ser inserida na rotina de manutenção preventiva dos tratores agrícolas, com a finalidade de identificação de possível contaminação por elementos externos, evitando assim que o sistema continue sendo contaminado até a chegada dos resultados das análises laboratoriais.

Active Control of the Inside Diameter of Diesel Engine Cylinder Liners during Their Honing

The changes in the inside diameter of liners during honing without active control means and with their use are studied. The inner surface of the liner is shown to wear out to a greater extent in its upper part. The causes of wear are indicated. The most common method for restoring a liner is mechanical treatment of the inner surface to an increased size. After boring to an oversize, honing process is shown to be applied. The pneumatic active control system used for honing is described. The method of evaluating the accuracy of the liner processing using the active control system is described. The inner surfaces of the liners processed with and without the active control means are measured. The use of the active control system during honing found to decrease the reject of exceeding the inner size tolerance of the cylinder liner from 45 to 1–2%. The active control system for honing cylinder liners is concluded to increase the processing efficiency by 15% due to the absence of measurement time with stopping processing and to decrease the reject in the inner surface size of the liners to 40%.

Digital technologies for processing equipment reliability management when providing its service

The system for managing the operational reliability of oil production equipment using digital technologies can be based on the identified inter-element interaction and the interaction scheme of the elements of the human-machine system. As a result of experimental studies, the following parameters were established: distribution of failures by groups of complexity; characteristics of failures from the point of view of the theory of reliability by groups of complexity, distribution of time to eliminate failures by groups of complexity. Investigation of the causes of wear of assemblies and parts of oil-extracting equipment, as well as taking into account the factors of reduced performance that affect wear, will prevent equipment failure, increase the technical readiness factor, and reduce the cost of repair and equipment downtime The scheme of reliability management at oil-extracting enterprises is proposed.

Wear Behavior of a Bio-inspired Bearing for off-center Loads

Misalignment is one of the most common causes of wear in bush bearings. Design improvements have been proposed by many researchers. Unfortunately, it did not efficiently reduce the misalignment. Classic geometrical designs sometimes reach their limits. For this reason, a bio-inspired design is proposed to solve the impediment. In this article, a bio-inspired bearing suited to misalignment was tested and compared to a classical bush bearing. The contact pressures of both bearings were compared with static Finite Element (FE) simulations for off-center load. Due to the complex shape of the involved contact, the performances of both bearings were also studied over time. Their wear behaviors were predicted with a numerical method. The methodologies emplaced to simulate the wear were described in this paper. Particularly, the wear coefficient determination obtained by experimental testing was detailed. The pressure value, the contact zone and the wear depth were compared and discussed. The wear results for the classical bearing are in accordance with the literature. The simulations show a deeper wear on the classical bush bearing than on the bio-inspired bearing. This leads to a longer period of service life for the bio-inspired bearing.

Wear Surface Studies on Ejector-nozzle in Circulating Fluidized-Bed Gasifier

ABSTRACT A key component of a circulating fluidized-bed gasifier is the recycling control device, which is important for stable solid circulation and combustion of particles. In our previous work, a steam–solid ejector was used as a recirculating control device to provide a continuous and stable pressure barrier, which reduced the amount of unburned combustibles in the fly ash. Damage to the ejector nozzle seriously affected the combustion stability and effective syngas concentration. The causes of wear of the nozzle surface were analyzed using a combination of methods. Computational fluid dynamics showed that the radial velocity near the nozzle zone approached 10–12 m/s and obvious erosion appeared on the surface of the nozzle. Scanning electron microscopy and energy-dispersive spectroscopy indicated that the direction of grooves that appeared on the worn nozzle surface was the same as that of the gas–solid flow and that the Ni-based structure of the original material was seriously damaged.

Droplet Size Distribution Characteristics of Aerial Nozzles by Bell206L4 Helicopter under Medium and Low Airflow Velocity Wind Tunnel Conditions and Field Verification Test

To investigate the spray atomization characteristics of aerial nozzles adapted to manned agricultural helicopters under medium-low airflow velocity (0 to 27.8 m/s) conditions, the droplet size test was carried out in both wind tunnel and field tests. In the wind tunnel test, the laser diffraction device (LDD) was used to test the spray droplet size of CP02, CP03, and CP04 aerial nozzles. A Bell206L4 helicopter was used in the field test. The results in the wind tunnel test showed that due to the nozzles had been used for a long time and the cause of wear, the spray stability of individual nozzles was affected during the test. The limitation of droplet size measurement by using LDD was also found. The field test results showed that the main distribution range of the droplet size measured in the field test was consistent with the results of the wind tunnel test, but the droplet size value was significantly higher and the uniformity of droplet size distribution was poorer than the wind tunnel test value due to the influence of the actual environment. However, the results of field test and wind tunnel test can still be used as a reference for each other.

Final plasma hardening the details of peristaltic pumps

Improving the reliability and durability of peristaltic pumps is urgent. (Research purpose) The research purpose is to consider the operating conditions of peristaltic pump saddle, determine the causes of wear, develop a methodology for selecting the optimal coating, conduct research on the physical and mechanical properties of coatings and test them for microabrasive wear. (Materials and methods) The process of finishing plasma hardening with diamond-like DLCPateks coating was chosen for research based on the analysis of well-known industrial coating technologies. The article describes the studied physical and mechanical properties using the nanoindentation method on the TI 750Ubi nanohardness tester (Hysitron, USA) and conducted tests under microabrasive wear conditions on the Tribotester 103PC device to analyze the effectiveness of using this coating in comparison with other wear-resistant coatings. (Results and discussion) It was found by studying the physical and mechanical properties of the DLCPateks coating with a thickness of about 1 micrometer applied by the final plasma hardening method that its wear resistance parameters are: the plasticity index is 0.14-0.16, the plastic deformation resistance is 0.41-0.57. It was noted that the closest analog according to these characteristics is a diamond-like a-C:H coating, applied by the method of physical deposition of coatings in a vacuum, has a value of the plasticity index of 0.1-0.16. (Conclusions) The article describes the result of testing under microabrasive wear conditions, the coefficient of wear resistance of the DLCPateks coating. The results of studies of the physical and mechanical properties of the DLCPateks coating applied by the final plasma hardening method have shown its effectiveness in improving the reliability of peristaltic pump saddles.

Failure analysis concerning causes of wear for bridge crane rails and wheels

Wear of the guiding structures is an undesirable phenomenon, which is occurring very often in the technical practice. This negative phenomenon also reduces reliability level of the hoisting machines and machinery. Taking into consideration the practical point of view it is possible to specify that wear of the crane guiding structures means wear of the crane rails and crane wheels. The guiding structure is defined in this case as a cinematic couple “wheel-rail”. There is presented in the article an experimental and calculation analysis, which was performed in order to investigate an excessive wear of the crane guiding structure, namely in the case of the hoisting equipment utilised in a real operation. There were experimentally researched two bridge slab tong cranes with the loading capacity 50 t and also their crane runways. It was determined, according to the performed analyses that in the case of one crane the geometry of its undercarriage is incorrect. The experimental measurements confirmed a fact that the real value of the horizontal force was approximately 3.8-times higher in comparison with the assumed force value obtained from a calculation. Another finding was that also the crane runway geometry exceeded values of the permitted deviations with regard to the valid technical standard. There is described in the chapter Conclusion a proposed short-term solution, which is able to eliminate wear of the crane rails and crane wheel flanges, however without prevention of the crane skewing.

Wear Life of Filtration Sleeves during the Industrial Operation of Fabric Filters

The uneven wear problems of filtration sleeves during their industrial operation are analyzed. The experimental data made it possible to establish the causes of wear and to determine the criteria for wear. The relationship between the filtration rate and the service life of the sleeves is established using experimental data. Mathematical dependences that make it possible to predict the service life and wear life of the sleeves during their operation are found. Devices that make it possible to increase the service life of filtration sleeves and reduce their wear life are developed based on the results.

Identifying reasons for failure of soil processing units of working bodies

The causes of wear of the working bodies of soil cultivating units are analyzed. The main culling parameters are presented, due to which the working bodies lose their performance. The analysis of factors affecting the degree of wear of working bodies is carried out. Theoretical recommendations are proposed for the creation of an equal-strength tillage unit, the working bodies of which wear out with equal intensity.