Ferrographic Analysis Research Articles

Performance studies on Tufftrided plain carbon steel journal bearings under mixed lubrication conditions

Tufftride-treated plain carbon steels were found to behave satisfactorily as journal bearing materials under conditions of mixed lubrication. Wear took place by ploughing and severe plastic deformation of the surface. Subsurface cracks when developed gave rise to flake-like wear debris. Ferrographic analysis of wear debris aided in the prediction and analysis of failure in these bearings.

Failure analysis of liquid-nitrided low carbon steel gears

The results of experimental investigations of hobbed and low temperature liquid-nitrided low carbon steel gears conducted in a back-to-back gear test rig are presented. Scanning electron microscopy and optical microscopy studies were carried out to understand the nature of the failures. Ferrographic analysis of the lubricating oil gave a good correlation with the observed data. An extensive programme of testing is necessary before a definite conclusion can be drawn about the prediction by ferrography of the onset of gear failure.

Ferrographic analysis of wear debris generated in locomotive diesel engines

A preliminary trial in which ferrography was applied to the condition monitoring of locomotive diesel engines is described in this paper. Typical particles generated by locomotive diesel engines are illustrated. Results of observations of those particles are discussed.

Ferrographic and spectrometer oil analysis from a failed gas turbine engine

An experimental gas turbine engine was destroyed as a result of the combustion of its titanium components. It was concluded that a severe surge may have caused interference between rotating and stationary compressor parts that either directly or indirectly ignited the titanium components. Several engine oil samples (before and after the failure) were analyzed with a Ferrograph and with plasma, atomic absorption and emission spectrometers to see whether this information would aid in the engine failure diagnosis. The analyses indicated that a lubrication system failure was not a contributory factor in the engine failure. Neither an abnormal wear mechanism nor a high level of wear debris was detected in the engine oil sample taken just prior to the test in which the failure occurred. However, low concentrations (0.2–0.5 ppm) of titanium were evident in this sample and samples taken earlier. After the failure, higher titanium concentrations (more than 2 ppm) were detected in oil samples taken from different engine locations. Ferrographic analysis indicated that most of the titanium was contained in spherical metallic debris after the failure. Attempts to pinpoint the failure initiation site were inconclusive, but the oil analyses did eliminate a lubrication system bearing or shaft seal failure as the cause of the engine failure.

Condition monitoring of marine diesel engines through ferrographic oil analysis

Condition monitoring of marine diesel engines through ferrographic oil analysis

Advances in quantitative analytical ferrography and the evaluation of a high gradient magnetic separator for the study of diesel engine wear

Several sources of variation in quantitative analytical ferrography are investigated. A standard ferrography analysis procedure is developed. Normalization of ferrographic data to account for the amount of oil used to make the Ferrograms is discussed. Procedures to minimize the errors involved in calculating three quantitative ferrography parameters, i.e. the area A L (% (ml of oil) −1) covered by the large particles, the area A S (% (ml of oil) −1) covered by the small particles and the area under the curve (millimeters per cent per milliliter of oil) are outlined. Ferrographic data are presented which show that the volume and dilution ratio of the oil sample being analyzed have a major effect on the accuracy of the analysis. Several variables which influence the area-covered readings of the particle deposit on a Ferrogram are discussed. The accuracy of quantitative analytical ferrography is assessed. Quantitative analytical ferrography is used to evaluate a high gradient magnetic separator (HGMS), both as a tool for engine wear research and as an oil filter. Laboratory tests indicate that the HGMS is an order of magnitude more efficient than conventional paper oil filters in removing magnetic wear debris from the lubricating oil.

Optimization of ferrographic oil analysis for diesel engine wear monitoring

An experimental investigation of the effectiveness of ferrographic methods applied to diesel engine wear monitoring was carried out. A series of car engines running in service were considered and the wear phenomena were studied on the basis of total particle density and large particle concentration trends determined through ferrographic analysis of oil samples. Results have shown that ferrography can be successfully used in this specific application.

Abnormal wear of gear couplings — a case study

A number of failures occurred in the gear coupling transmitting the torque from a steam turbine (rotating at 7500 r/min) to a 1.5 MW generator through a 1 : 5 reduction gear box. Failure was found to be occurring in the form of rapid wear of teeth. Heavy wear steps were notices on both the hub and the spool pieces. Vibration measurements revealed that twice the running speed component was the most dominant frequency, with the maximum amplitude in the axial direction, indicating misalignment. Non-synchronous components appearing in the frequency spectrum revealed that rubbing was taking place. Overall vibration analysis at different locations in the assembly indicated seating problems in the bearing pedestals with the bed plate. Excessive sludge accumulation was noticed in the gear coupling. Analysis of the sludge indicated the presence of large quantities of iron oxide, water, calcium and silica. Other elements of the gear coupling material were also present. However, no deviations in the physical and chemical properties were found through analysis of oil collected from the tank. Examination of the lubrication system showed lack of proper filters and centrifuge. The shape, size and orientation of the nozzle for the oil jet to gear coupling were found to be incorrect. Ferrographic analysis of the lubricating oil revealed a large quantity of wear particles. It was concluded that the wear was due to the misalignment aided by faults in the lubrication system

Advances in ferrographic analysis of wear debris (techniques evolved to enhance the use of ferrography)

Advances in ferrographic analysis of wear debris (techniques evolved to enhance the use of ferrography)

‘Comparison of spectrographic and ferrographic analysis of crankcase oils from the High Speed Train’: G.R. Morley, Tribology International, June 1981, 14(3), 159–165

‘Comparison of spectrographic and ferrographic analysis of crankcase oils from the High Speed Train’: G.R. Morley, Tribology International, June 1981, 14(3), 159–165

The effect of oxygen concentration on the boundary-lubricating characteristics of a C ether and a polyphenyl ether to 300 °C

The effect of oxygen concentration on the boundary-lubricating characteristics of an unformulated C ether (modified polyphenylether) was studied with the use of a ball-on-disk sliding friction apparatus. Experiments were performed in atmospheres with oxygen concentrations of 20% (air atmosphere) and 0.001% (nitrogen atmosphere) and with five intermediate oxygen concentrations. Results were compared with those obtained with a five-ring polyphenylether in two atmospheres (air and nitrogen). The other experimental conditions included a load of 1 kgf (initial Hertz stress, 10 9 N m −2), a sliding speed of 17 m min −1 (100 rev min −1), disk temperatures ranging from 25 to 300 °C and a test duration of 25 min. Test specimens were made of consumable electrode vacuum melted steel CVM M-50. The C ether yielded lower wear and lower friction coefficients than a five-ring polyphenylether in air (20% O 2) and nitrogen (0.001% O 2) over most of the temperature range. The C ether exhibited lower wear at high oxygen levels (10% – 20% O 2) from 25 to 200 °C and at low oxygen levels (0.001% – 1.0% O 2) from 200 to 300 °C. Friction polymer was observed around the wear scars of most test specimens. However, ferrographic analysis indicated that much greater quantities of friction polymer were produced in a low oxygen environment. Therefore the C ether behaves, qualitatively, like the polyphenylether with respect to friction polymer production.

Comparison of spectrographic and ferrographic analysis of crankcase oils from the High Speed Train

Spectrographic analysis has been in use for some years as a routine preventative maintenance tool to detect early failures of diesel engines, including those of the High Speed Train (HST). Ferrography is a newer technique which is claimed to have merit in condition monitoring of lubricants in service, but few workers have attempted to apply it to the diesel engine. This paper compares the two techniques for the engines of the HST.Spectrographic analysis indicated two problems on one of the seven engines monitored weekly which ferrography did not detect. For three other engines where spectrographic analysis had given critical results, ferrography was of little help. Moreover, on three other engines ferrography could have led to unnecessary engine examination. It is concluded that ferrography is of limited value in either the direct read or analytical modes in this application which involves a high proportion of non-ferrous components, whereas spectrographic analysis continues to be an invaluable preventative maintenance tool

Synovial fluid analysis by ferrography

Ferrography is a technique for magnetically harvesting and separating metallic particles from aqueous and non-aqueous suspensions. We have adapted this method of analysis to the study of cartilaginous and osseous wear particles, as well as fragments of soft tissue, found in the synovial fluid of human joints. As ferrography employs magnetism to harvest particles and arrange them in an orderly fashion, it is first necessary to impart a positive magnetic susceptibility to the biological materials. The trivalent paramagnetic cation of the rare earth element erbium is used for this purpose. Based on this principle, a method for the ferrographic analysis of snyvial fluid has been devised, which is presently being employed in the study of human joint disease. Using this technique, improved diagnosis of arthritis may be possible. In addition, it may lead to a deeper understanding of the aetiology and pathogenesis of degenerative arthritis and other destructive joint diseases.

Ferrographic Analysis of Wear Debris Generated in Accelerated Rolling Element Fatigue Tests

Ferrographic analysis was used to determine the types and quantities of wear particles generated during accelerated rolling contact fatigue tests. The NASA five-ball rolling contact fatigue tester was used. Ball specimens were made of AMS 5749, a corrosion resistant, high-temperature bearing steel. The lubricant was a super-refined naphthenic mineral oil. Conditions included a maximum Hertz stress of 5.52 × 109 Pa and a shaft speed of 10 000 rpm. Four types of wear particles were observed; normal rubbing wear particles, fatigue spall particles, spheres, and friction polymer. Presented as an American Society of Lubrications Engineers paper at the ASLE/ASME Lubrication Conference in Kansas City, Missouri, October 3–5, 1977

Ferrographic analysis of wear particles in arthroplastic joints.

Analysis of aspirated synovial fluid appears to be a useful method for the study of the rates, mechanisms, and biological responses to wear in surgical joint replacements. Ferrography, an industrial technique of magnetic separation of particulate matter from samples of lubricating solutions, allows separation of wear debris from synovial fluid. Bichromatic microscopy and SEM X-ray analysis permit identification of metallic particles from arthroplastic joints. Polarized light microscopy characterizes and differentiates polyethylene and polymethacrylate debris. The number and morphology of the wear particles in synovial specimens from arthroplastic joints correlate with the rate and the mechanisms of wear, as confirmed by examination of the implant and the adjacent synovial tissue.

Condition monitoring of gas turbines — An exploratory investigation of Ferrographic trend analysis

To aid the application of Ferrogaphic analysis to machine condition monitoring, a programme of trend analysis of gas turbine engines of the same type in the fleet of a single operator was carried out using the direct reading Ferrograph. The most informative method was found to be cumulative plots of the total wear and severity of wear on the same graph. Convergence of the curves gives an early warning of uncharacteristic trends which should be investigated by full Ferrographic analysis; a cross-over of the curves indicates that urgent action is required.

Asperity Interactions In EHD Contacts

Infrared temperature measurements, ferrographic analysis, and surface profilimetry were used to monitor asperity interactions in a sliding EHD point contact. The contact temperature and surface profile signals obtained both before and after a run-in period are compared in the frequency domain by means of a Fourier analyzer. The interaction of surface asperities is accompanied by the presence of a high frequency component in the infrared signal. It is also shown that only a relatively narrow band of wavelengths of the surface profile spectrum are relevant in the interaction process.

Ferrographic Analysis of Wear Debris Generated in a Sliding Elastohydrodynamic Contact

The Ferrograph has been used to analyze wear debris generated in a sliding elastohydrodynamic contact. The amount of wear debris correlates well with the ratio of film thickness to composite surface roughness (Λ ratio). Essentially all of the generated wear particles were of the normal rubbing wear type.

Ferrographic Analysis of Wear Debris from Boundary Lubrication Experiments with a Five Ring Polyphenyl Ether

The types of wear particles generated by a five-ring polyphenyl ether in boundary lubrication experiments in various atmospheres were determined by ferrographic analysis. The types of wear particles observed included cylindrical or rocklike organometallic debris, adhesive and cutting wear particles, and some spherical debris. Interpretations as to the mechanism of generation of the various types of particles are presented.