Examination of wear debris produced using a four-ball machine

Leng, Jianghao; Davies, J. V.

doi:10.1016/0301-679x(89)90174-6

Cited by 5 publications

(4 citation statements)

References 10 publications

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“…However, others have found no such correlation and question the validity of the plasticity index in predicting scuffing failure in practical situations, where sliding speeds are much higher and the amount of asperity plastic flow is much greater [72]. The suggestion that scuffing occurs in the early stages of plastic deformation is also not supported by other results, where high levels of plastic flow have been observed [51,58].…”

Section: Empirical Formulacontrasting

confidence: 43%

“…This model of plastic deformation causing asperity plastic fatigue is supported by the examination of wear debris collected from four-ball tests [51] and failed cams and tappets [58]. The scuffed surfaces examined indicated high levels of plastic flow and exhibited damage features in the form of delamination indicating fatigue failure.…”

Section: Asperity Interaction Modelsmentioning

confidence: 92%

“…It is generally accepted that temperatures in excess of 150~ and as high as 800~ associated with scuffing are accompanied by untempered martensite transformations in four-ball tests [51]. At these elevated temperatures the role of the lubricant is called into question.…”

Section: Lubricant Decomposition Modelsmentioning

confidence: 99%

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A review of scuffing models

Bowman

Stachowiak

1996

Tribol Lett

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The mechanism of wear known as scuffing has been a research topic of great interest for many years. However, the question of how scuffing is initiated and the factors that contribute to its occurrence are still poorly understood. In general, it can be said that scuffing manifests itself as the sudden failure of lubricating films in mechanical equipment operating under extreme conditions of load and/or speed. Components such as cams, tappets, gears and piston rings are all prone to scuffing failure. Understanding the mechanisms that initiate failure would enable the development of criteria for scuffing prediction. This paper reviews the numerous scuffing models and theories that exist today and, in doing so, defines the important factors involved in scuffing initiation. Emphasis is given to existing theoretical scuffing models which have been correlated by a wealth of research data obtained from experimental test rigs.

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Section: Empirical Formulacontrasting

confidence: 43%

Section: Asperity Interaction Modelsmentioning

confidence: 92%

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A review of scuffing models

Bowman

Stachowiak

1996

Tribol Lett

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“…Using transmission electron microscopy, Torrance et al [29] found a very fine martensite structure in the white layer. Leng et al [30] proposed that the white layer was a form of microscopic friction weld between asperities and that its formation mechanism was similar to that of adiabatic shear bands [31][32][33]. Ajayi et al observed the microstructural changes in the near-surface material before, during, and after scuffing, and indicated that a severe deformation layer was formed during scuffing [34].…”

Section: Introductionmentioning

confidence: 99%

In Situ Observation of Heat Generation Behaviour on Steel Surface During Scuffing Process

2018

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In the current study, the heat generation behaviour at plastic flow area in the contact area during a scuffing process was observed in situ using a monochrome high-speed camera that detected both visible and near-infrared light. The scuffing test was conducted using a pin-on-disc test rig comprising a rotating sapphire disc and a fixed martensitic steel pin. Engine oil was supplied as a lubricant. The images captured by the high-speed camera clearly showed changes in the contact area and the heat generation behaviour. It was found that the heat generation behaviour could be classified into three stages during scuffing. In the first stage, local heat generation occurred intermittently at local severe contact points, such as the passing of transfer layers on the sapphire disc and the trailing edge of the contact area. In the second stage, heat generation occurred intermittently over larger areas in which heat had been generated until that time. When the entire contact area had previously generated heat, heat generation became continuous throughout the contact area in the third stage. During the third stage, the contact area was increased rapidly, which caused catastrophic failure. These results highlight important questions regarding material phenomena that remain to be investigated.

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