Ring Wear Research Articles

Study on the Abrasive Wear of Mo-Alloy Sprayed Piston Ring

This paper takes the SRV friction and wear tester, conducts the research on the abrasive principle of the tribomate pairs (Mo-alloy sprayed piston ring/P-B cylinder bore) under the condition that there lies a certain amount of quartz sand in the lubricant and find that the surface structure, chemical component of tribomate materials can have a huge influence on its capability of resisting abrasion.

English

A rotor dynamic model is developed by using finite element method (FEM), The rotor includes impellers, bearings and seals.The object of the analysis is to calculate the critical speeds of a rotor to find out if there are sufficient margins of separation between critical speed and the rotor operating speed. Lateral resonant frequencies can excite on the rotor and result in high damaging rotor vibration. The torsional critical speed of rotating machinery components is an important consideration in defining the operational reliability of the rotary equipment train. Pump is mainly a 4 staged centrifugal pump, the modal analysis of the centrifugal pump is performed using ANSYS workbench is used as a FEA tool to find critical speeds or rotor natural frequencies. To meet the higher target of power, machines have to run at higher speeds then pump shaft will be subjected to higher lateral and torsional vibrations because of gyroscopic effect and centrifugal force of the rotating elements mounted on the shaft. The resonance is produced when the rotor natural frequency coincides with operating frequency, the deflection of the rotor will be maximum. To avoid resonance condition, it is necessary to evaluate all stiffness and damping coefficients of wear rings, mechanical seals, throttle seals and bearings. In this work an attempt is made to evaluate the Lateral critical speeds using ANSYS software by plotting Campbell diagrams and is compared with theoretical calculations and RBTS (Rotor Bearing Testing Software). It is very difficult to eliminate all interference points in the system since there are so many external excitations. The rotor has been designed and analyzed by using the guidelines as per API 610 standards.

Piston ring wear and cylinder liner tribofilm in tribotests with lubricants artificially altered with ethanol combustion products

To investigate the effects of bioethanol on the piston ring–cylinder liner system, tribological tests were carried out on a model tribometer set-up, measuring friction and piston ring wear. The bioethanol influence is accounted for by adding ethanol combustion products during an artificial engine oil alteration process and using these lubricants in the tribotests. Also, a chemical surface analysis of the wear zone on the cylinder liners was carried out. There is a significant difference in the performance of these artificially altered oils in comparison to their fresh counterparts, and different lubricants are affected differently by the alteration process. A close correlation was found between the steady-state wear rate of the piston ring and the tribofilm thickness on the cylinder liner.

Influence of severe shot peening on wear behaviour of an aluminium alloy

ABSTRACTRecent developments in shot peening demonstrate that it can be applied using unconventional parameters in order to obtain nanocrystals on a thin surface layer of the treated material. These microstructural modifications have shown to be able to induce superior fatigue and corrosion properties, but still few data are available about their effect on wear behaviour of the materials.In this study, four series of Al 6063 alloy specimens, as‐received, conventionally shot peened, severely shot peened and severely shot peened followed by a slight mechanical grinding are subjected to block on ring wear tests with lubrication, according to ASTM G77 standard. The results evidence the significant role played by the applied shot peening treatments on wear behaviour of the 6063 aluminium alloy with respect to the as‐received not peened material. The important effect of the surface roughness is also highlighted. The data are discussed on the basis of roughness, surface layer microstructure, microhardness trends and the wear marks observed by means of scanning electron microscopy.

Effect of Karanja biodiesel blend on engine wear in a diesel engine

For large-scale and reliable implementation of biodiesel in transportation engines, its effects on engine wear and engine durability upon prolonged usage needs to be experimentally investigated. Therefore effects of 20% Karanja biodiesel blend (KOME20) on engine wear and durability was studied vis-à-vis mineral diesel in 250h long endurance test on a direct injection compression ignition (DICI) engine. Visual inspection of engine components for deposits indicted higher carbon deposits on piston top, cylinder head and injector tip for biodiesel fuelled engine. Relatively lower wear of valves, pistons, piston rings, liners and small end bearings of the connecting rods was observed for biodiesel fuelled engine. Wear of big end bearing of the connecting rods, main bearings and crank pins was found to be higher for biodiesel fuelled engine. Surface texture of cylinder liners remained in acceptable condition after the endurance test for mineral diesel as well as Karanja biodiesel blend. Despite higher carbon deposits and higher wear of some vital engine components, no operational problems were observed during the long-term endurance test for the biodiesel fueled engine.

Synthesis and characterization of rapeseed oil bio-lubricant dispersed with nano copper oxide: Its effect on wear and frictional behavior of piston ring–cylinder liner combination

Direct application of vegetable oil as automotive lubricants is less favorable due to its poor thermo-oxidative stability, cold flow behavior, and poor anti-wear characteristics. The investigation detailed in this paper pertains to chemical modification of rapeseed oil through epoxidation, hydroxylation, and esterification processes in order to improve its thermo-oxidative stability and cold flow behavior. The copper oxide (CuO) nanoparticles of size ∼40–70 nm was dispersed in chemically modified rapeseed oil (CMRO) in three different concentrations (0.1 wt%, 0.5 wt%, and 1 wt%) as an anti-wear additive using an ultrasonic sonicator. The tribological behavior of cylinder liner against piston ring segment was tested with CMRO with and without CuO nano-additive using high frequency reciprocating rig tribometer. The morphological characterization of CuO nanoparticles dispersed in CMRO was done using scanning electron microscopy and X-ray diffraction analysis. The results were also compared with commercial synthetic lubricant under the same operating conditions. The atomic force microscopy and scanning electron microscopic analyses proved that the surface morphology of tested cylinder liner surfaces are smooth with optimum concentration of 0.5 wt% CuO nanoparticles dispersed in CMRO.

Effect of Carbides on Wear Characterization of High-Alloy Steels under High-Stress Rolling–Sliding Condition

This article describes the wear characterizations of high-speed steel composed of vanadium carbide and high-chromium cast iron composed of chromium carbide. These metals were studied under rolling–sliding conditions with a sliding ratio of 10% using a self-made ring–ring wear testing machine. The fine microstructure of carbides and failure behaviors were analyzed by scanning electron microscopy and high-resolution electron microscopy. The results showed that carbide significantly affected the wear properties and failure behaviors of metals. The relative wear resistance of high-speed steel reinforced by vanadium carbides was twice that of high chromium cast iron composed of chromium carbides. Chromium carbide was characterized by a stacking fault substructure, and slips occurred in chromium carbide under high-stress contact, resulting in crack formation. Vanadium carbide was reinforced and pinned by large amounts of nanoparticles, which prevented its dislocation under high-stress rolling–sliding conditions, thereby effectively resisting crack initiation. Furthermore, the (200) lattice plane of vanadium carbide is coherent with the (111) lattice plane of austenite, preventing cracks from forming at the interface of the vanadium–carbide matrix. The morphology and hardness of vanadium carbide also contributed to the excellent wear property of high-speed steel.

Investigation on the application of YAG laser texturing technology to the cylinder wall of auto engine

Purpose – The purpose of this study was to develop a new approach using a pulse YAG laser with rational power density and pulse width to texture desired discrete distribution morphology on the cylinder wall. Design/methodology/approach – Variational rules of the effects of these three parameters were found by calculating the oil film on the cylinder/piston ring system. The experiment results were compared between laser texturing cylinders and conventional honing cylinders. Findings – It was found that the coefficient of friction and wear rate of laser texturing cylinders were reduced by 50 and 85.7 per cent, respectively, and the piston ring wear rate was decreased by 50 per cent under full lubrication condition. Under starved lubrication condition, the cylinder liner wear was reduced by 34.3 per cent. Originality/value – The effectiveness of which was determined by three control parameters: depth-to-diameter ratio, area density and distribution angle of the dimples.

Interactions of Diamond-Like Carbon Coatings with Fully Formulated Engine Oils

Diamond-like carbon (DLC) coatings have been known for their low friction and high wear resistance for many years, but only in recent years have these coatings been used in mass-produced engines due to significant improvement in coating deposition techniques resulting in good adhesion on substrate materials. The interactions of these coatings with engine oils have been a focus for further research in recent years. In this investigation, the interactions of engine oil additives with five different DLC coatings containing two different doping elements were explored using a laboratory reciprocating rig under boundary lubrication condition. Two different contact geometries were investigated: a piston ring-on-liner and cylinder-on-flat to simulate piston ring and cylinder bore and cam and tappet applications. It was observed that DLC-coated piston rings offered lower friction coefficients and lower wear of the liner compared to commonly used Mo-NiCr-coated piston rings. However, the wear of the DLC-coated rings varied. The presence of lubricant additive–derived films could be observed on the wear surfaces of three of the DLC-coated surfaces irrespective of their doping element. In addition, the thickness of the lubricant additive–derived films on DLC-coated surfaces (a) was lower than that formed on ferrous materials and (b) depended on engine oil formulations.

Investigation into Transient Flow in a Centrifugal Pump with Wear Ring Clearance Variation

The leakage flow paths in the sidewall gaps of centrifugal pumps are of significant importance for numbers of effects. The paper is concerned with the transient flow in the leakage flow paths with wear ring clearance variation. For this purpose, numerical simulations of the whole pump were carried out. The grid dependence and yplus check were performed first. Additionally, experimental data of performance characteristic and pressure fluctuation inside the sidewall gap was used to validate the numerical results. The transient velocity fields inside the sidewall gaps during one blade passage period were simulated. And the leakage through the wear ring gap was obtained for all operating points investigated. To have a better idea of attenuation and propagation of pressure inside the sidewall gap, the unsteady pressure distributions in the gap were calculated. Additionally, the surfaces of the impeller were divided into four parts. The fluid force on each part was expressed as a percentage of the total radial force. Through comparing the flow fields, the pressure distributions, and the radial force between the pumps with different wear ring clearances, the effects of the wear ring clearance were discussed in detail. The results can be used to guide the optimum design of the pump sidewall gaps.

Study on the Abrasive Wear of Ceramic Piston Rings and the Different Cylinder Bore

The paper takes the SRV friction and wear tester, conducts the research on the abrasive ability of the three tribomate pairs (ceramic piston ring and P-B, Cu-Cr-Ni-Mo and bainite cylinder bores) under the condition that there lies a certain amount of quartz sand in the lubricant and find that the more hardness of cylinder bores, the more capability of resisting abrasion. The capability of resisting abrasion of ceramic piston ring/bainite cylinder bores is the best in three tribomate pairs.

Microstructure and wear resistance of Fe based TiB2 composite coating

Fe based TiB2 composite coating was in situ synthesised by plasma transferred arc cladding. The microstructure and microhardness of the composite coating were investigated by optical microscopy, SEM and microhardness tester. Sliding wear behaviour of the composite coating was investigated on a block on ring wear tester rubbing against GCr15 steel ring. Wear resistance of TiB2/Fe composite coating was 16–25 times than that of the uncoated iron matrix. The good interfacial bonding between TiB2 particles and iron matrix led to no transition from mild wear to severe wear over the applied load range. The sliding wear resistance of the composite coating decreased with increasing sliding speed and applied load. The wear mechanism of the composite coating was a comprehensive action of microcutting wear, surface flaking, adhesive wear, slight abrasive wear and fatigue wear. High applied loads resulted in particle detachment and accelerated the abrasive wear and the fatigue wear.

A mixture Weibull proportional hazard model for mechanical system failure prediction utilising lifetime and monitoring data

As mechanical systems increase in complexity, it is becoming more and more common to observe multiple failure modes. The system failure can be regarded as the result of interaction and competition between different failure modes. It is therefore necessary to combine multiple failure modes when analysing the failure of an overall system. In this paper, a mixture Weibull proportional hazard model (MWPHM) is proposed to predict the failure of a mechanical system with multiple failure modes. The mixed model parameters are estimated by combining historical lifetime and monitoring data of all failure modes. In addition, the system failure probability density is obtained by proportionally mixing the failure probability density of multiple failure modes. Monitoring data are input into the MWPHM to estimate the system reliability and predict the system failure time. A simulated sample set is used to verify the ability of the MWPHM to model multiple failure modes. Finally, the MWPHM and the traditional Weibull proportional hazard model (WPHM) are applied to a high-pressure water descaling pump, which has two failure modes: sealing ring wear and thrust bearing damage. Results show that the MWPHM is greatly superior in system failure prediction to the WPHM.

Experimental Investigation of Influence of Different Surface Textures on Wear Characteristics of Straight Type Diesel Engine Cylinders

To investigate antiwear properties of straight type diesel engine cylinders, an SRV IV wear tester was used to measure dynamic friction coefficient and wear depth by simulating working condition of cylinder liner and piston ring. The worn surface topography was observed through scanning electron microscope. The results show that the wear of piston ring is greater than that of cylinder in the same pair of friction. In three groups the average friction coefficient and the wear amount of honing cylinder is the minimum, followed by the smooth cylinder. The wear amount of grooves - micropitting composite textured cylinder is the maximum. The main wear form of three groups cylinders is fatigue, accompanied by two body abrasion.

The Wear Mechanism Analysis for the Surface of Aluminum Brass in Recoil Brake

To study the malfunction cause and wear mechanism of aluminum brass in gun recoil brake, based on microscopic analysis technology, scrapped throttling ring from the repair facility as research objects, the throttling ring wear mechanism is analyzed systematically from the microscopic point integrated use of metallurgical microscope analysis, scanning electron microscopy and energy dispersive spectrometer analysis. Studies show that, as one of the vital components in recoil brake, the throttling ring made of aluminum brass is due to the composite role of erosive abrasion, chemical corrosion and cavitation damage leading to failure. The method can provide reference for the improvement of the throttling ring and the failure analysis of similar alloy parts.

Wear properties of H13 with micron scale and nano scale grains bionic units processed by laser remelting

By simulating the cuticles of some soil animals, a combination of soft part (untreated substrate) and hard part (laser remelting area) structure was designed on metal surface to get an improved performance. Different specimens were prepared which contained units with micro and nano scale grains. The microstructures were observed by environmental field emission scanning electron microscopy. X-ray diffraction was used to identify the phases. The results of these tests indicate that due to the rapid solidification condition in the water, nano scale grains have a high microhardness between 1300 and 1000 HV. Retained austenite was found in it. Some of them transform to martensite in block on ring wear test. Specimens with bionic unit have a better wear resistance. Especially, the units with nano grains bring a further enhancement. The alternate soft and hard in macroscopic (substrate and laser remelting area) and microscopic (austenite and martensite) structure played a key role in improving the H13 wear resistance.

Tribological properties and failure analysis of PTFE composites used for seals in the transmission unit

The sealing rings are one of the most important components as the sealing devices in the wet clutch unit of a heavy vehicle. The sealing ring, made from PTFE composites, was subjected to serious wear on the sealing surface, but the mating metal surface only had slight abrasion. A specialized test rig was designed for wear research and failure analysis of the sealing ring. The composition analyses of the ring material, working conditions and wear surface characteristics by visual inspection and tribological properties as well as microscopic analysis with scanning electron microscope was performed to determine the wear mechanism and failure causes. Results revealed that the wear of PTFE composites was characterized by abrasion and adhesion after a certain duration testing, and the wear mechanism changed to thermal fatigue and abrasive wear in the stage of intense wear. The thermal deformation and fatigue were primarily responsible for the rapid wear of the PTFE composites for the sealing rings.

Piston ring and cylinder liner wear aggravation caused by transition to greener ship transports–Comparison of samples from test rig and field

New and upcoming emission regulations for ships will push towards greener sea based transports. Changing the fuel, from heavy fuel oil to natural gas, is a promising approach to fulfil these regulations, but tribological problems are expected to appear when the sulphur-free gas replaces the sulphur-rich heavy fuel oil. The aim of this study was to investigate the role of sulphur for the high performance of current tribosystem in the cylinder. Field worn samples were examined and no tribofilm containing sulphur was detected, but grain refinement and plastic deformation was found below the sliding surfaces. A reciprocating test rig was used in order to simulate the tribological conditions for the piston rings and cylinder liner. Tests were run with fresh cylinder oil as well as with used cylinder oil, where the latter was used in order to simulate the chemical environment in the cylinder of an engine. Tribofilms were formed on the surfaces during these tests, and the tribofilms formed on samples run with used cylinder oil contained more sulphur than tribofilms formed on samples run with fresh cylinder oil. So far, we have not been able to see any beneficial effects of higher sulphur content in the oil.

Effects of computational grids and turbulence models on numerical simulation of centrifugal pump with CFD

In order to verify accurately the effects of computational grids and turbulence models on CFD numerical simulation of centrifugal pump, the calculation results of the different mesh numbers coupling with five kinds of turbulence models are compared. These parts of models (e.g. wear ring and tongue) are meshed with the local refinement technology. At design condition, with CFX software on the Dawning TC3600 parallel computer cluster, the calculation results of phase coupling six different mesh numbers from 1 million to 25 million with five different turbulence models (K-Epsilon, SSG Reynolds Stress, K epsilon EARSM, RNG K-Epsilon, K-Omega) are used to make performance prediction and to analyze the internal flow field. And the comparison between performance prediction results and experimental results are analyzed. It is confirmed that the calculation results are quite different with different turbulence models, and the result under K epsilon EARSM model is better than the others. And it shows that the internal flow in centrifugal pump is depicted more perfect with the increase of mesh numbers.

Study on the Abrasive Wear of Chromeplate Piston Ring and Cylinder Jacket Made by Different Materials

The abrasion of piston rings/tribomate pairs of cylinder jacket has great damage to engine, which can shorten the life of piston rings and cylinder bore, decrease the power of engine, enlarge the amount of oil, and release more pollution. Take a research of abrasive wear of piston ring and cylinder jacket made by different materials, will create a positive influence on extending the life of engine. This paper takes the SRV friction and wear tester, conducts the research on the abrasive ability of the three tribomate pairs (Cr plated piston ring and P-B, Cu-Cr-Ni-Mo and bainite cylinder bores) under the condition that there lies a certain amount of quartz sand in the lubricant and find that the hardness, intensity and tenacity of tribomate materials can have influence on its capability of resisting abrasion.