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This research focuses on advancements in bearing steel technology, emphasizing the need for accurate evaluation methods for non-metallic inclusions and the development of slag refining techniques. It explores various studies on fatigue life predictions, performance under contaminated lubrication, and microstructural optimization of bearing steels, highlighting improvements in service life and resistance to extreme conditions. The paper concludes with discussions on the material composition's impact on bearing performance and suggests future directions in enhancing bearing technologies.
Mechanical Systems and Signal Processing, 2016
Precise prediction of the lifetime of rolling element bearings is a crucial step towards a reliable design of many rotating machines. For bearings subjected to highly varying loads, recent research emphasises a strong reduction of the actual bearing lifetime w.r.t. the classically calculated bearing lifetime. This paper experimentally analyses the influence of external dynamic loads on the lifetime of rolling element bearings. A novel bearing test rig is introduced. The test rig is able to apply a fully controlled multi-axial static and dynamic load on a single test bearing. Also, different types and sizes of bearings can be tested. Two separate investigations are conducted. First, the behaviour of the lubricant film between the rolling elements and raceways is analysed. Increased metallic contact or breakdown of the film during dynamic excitation is investigated based on the measured electrical resistance through the bearing. The study shows that the lubricant film thickness follows the imposed variations of the load. Variations of the lubricant film thickness are similar to the variations when the magnitude of the static bearing load is changed. Second, wear of the raceway surfaces is analysed. Surface wear is investigated after a series of accelerated lifetime tests under high dynamic load. Due to sliding motion between asperities of the contacting surfaces in the bearing, polishing of the raceway honing structure occurs. This polishing is clearly observed on SEM images of the inner raceway after a test duration of only 0.5% of the calculated L 10 life. Polishing wear of the surfaces, such as surface induced cracks and material delamination, is expected when the bearing is further exposed to the high dynamic load.
2013
"Bearing wear prognosis requires effective modelling and monitoring of rolling contact. Rolling contact wear is responsible for the damages initiating on and beneath the contacting surfaces. It is commonly observed in the experimental studies that rolling contact wear follows specific stages of initiation (i.e. debris, dentation, inclusions) and propagation (i.e. dents, micro-cracks, pits, spalls) over the lifetime. The initiation and propagation stages are functions of load induced stresses, material characteristics and operating conditions. Thus, different physical mechanisms are repre- sented in the evolution of rolling contact wear. Different monitoring techniques have limited physical capability. Therefore, the purpose of this paper is to describe the evolution of rolling contact wear, which is measured using different possible monitoring techniques. Dynamic response, stress wave, and debris particles are the main outcomes for each stage of wear progress. The paper utilises a proposed five-stage model of rolling contact wear progress in order to explore the measured outcome of contact mechanics: Running-in, steady-state, defect initiation (dentations, pits, inclusions), defect propagation (extended pits, propagated cracks), damage growth (spalls). The paper is relevant in exploring the possible measurement techniques for the prognosis of the development of rolling contact wear. "
The rating life of ball bearings is reduced when hard particle contaminants are present in the lubricant. Usually, this life reduction is taken into account in the calculation of modified rating life by using the contamination factor through a general characterization of the lubrication conditions. However, the impact of contaminant's variables such as size, hardness and concentration level should be specified in detail. In this work, greases contaminated with steel and alumina particles of the same size are tested with the purpose of finding examining the wear mechanism and its progress inside the bearings. A laboratory rig is utilized for these tests and vibration analysis is performed to estimate the condition and the residual life of the bearings. After the tests, optical inspections performed in a stereoscope verify the predictions of vibration analyses and give a graphical point of the wear. It was found that steel particles, after their initial deformation, produce milder...
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Heat Treat 2021: Proceedings from the 31st Heat Treating Society Conference and Exposition
Through hardened steel ball fatigue failure is an atypical mode of failure in a rolling element bearing. A recent full-scale bench test resulted in ball spalling well below calculated bearing life. Subsequent metallurgical analysis of the spalled balls found inferior microstructure and manufacturing methods. Microstructural analysis revealed significant carbide segregation and inclusions in the steel. These can result from substandard spheroidized annealing and steel making practices. In addition, the grain flow of the balls revealed a manufacturing anomaly which produced a stress riser in the material making it more susceptible to crack initiation. The inferior manufactured balls caused at least an 80% reduction in rolling contact fatigue life of the bearing.
Materials & Design, 2011
a b s t r a c t Flaking failure of rolling contact fatigue is known to originate from non-metallic inclusions, where fatigue cracks occur at subsurface region of materials. It is fundamental to understand the main factors governing the rolling contact fatigue life. Steel samples with different size and chemical composition of oxide inclusions were evaluated on rolling contact fatigue life. As a result, (i) Rolling contact fatigue life was improved by reducing the oxide size. (ii) Rolling contact fatigue life varied depending on the oxides composition.
Key Engineering Materials, 2007
Rolling contact fatigue (RCF) cracks initiated from surface and subsurface defects are typical failure modes of bearing systems. In this paper, the effects of surface defects on RCF behavior of M50NiL and M50 steels were studied experimentally. Artificial dents were introduced on the rolling surface by using Rockwell hardness tester. The influences of dent shape and dent shoulders were examined by thrust-type RCF tests. Surface cracks initiation, propagation and spalling were monitored by scanning electron microscope (SEM) observation. The results showed that artificial dents reduce RCF lives of M50NiL and M50 steels with mineral oil lubrication. The fatigue failure initiates at the surface defect with the effects of dent shape and dent shoulder. M50NiL steel has higher contact fatigue resistance than M50. The features of surface and sub-surface cracks propagation during RCF tests were also observed.
International Journal for Research in Applied Science & Engineering Technology (IJRASET), 2022
Excessive noise levels from wheels and brakes, tire wear levels, bearing hub wear, bearing humming, undercarriage noise, and other factors are considered in this study. According to the study findings, better design and fatigue life prediction are urgently needed to prevent accidents. Because the hub assembly on the left side of the vehicle experiences the most deformation and has the shortest fatigue life, the behavior of the wheel hub ball bearing under duty cycle loading conditions affects deformations and bearing life.
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