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ACRC Technical Report 147PDF


Title:Scuffing Under Starved Lubrication Conditions
Author(s):Yoon, H.K.; Cusano, C.
Abstract:A few among many otherwise highly successful lubricated sliding components fail catastrophically and without warning. This sudden mode of failure is often called scuffing. The phenomenon of scuffing has been known for many years and numerous attempts have been made to understand its processes and mechanisms. There is still, however, a general lack of agreement concerning the processes leading up to scuffing. One of the main reasons for this is that the detailed mechanisms of scuffing are not well understood. The main purpose of this study is to obtain a better understanding of the scuffing processes and material failure mechanisms under starved lubrication conditions. The research focuses on two major goals. The first is to examine the scuffing behavior of 52100 steel shoes/390-T6 Al plate contacts under starved lubrication conditions. The evaluation is based on a shoe-on-disc geometry which approximately simulates the swashplate/ shoe contacts in an automotive swashplate compressor. All tests are conducted in a high pressure tribometer (HPT) under R134a environment with a base polyalkylene glycol (PAG) lubricant. The effects of degree of lubricant starvation, sliding velocity, geometry of contact, surface topography, a tin coating, and socket geometry supporting the shoe are evaluated. The second goal is to study the processes and mechanisms of the scuffing phenomenon also under starved lubrication conditions. A pin-on-disc geometry is used to examine the effect of materials, lubricant/refrigerant mixtures and loading history on scuffing. The transition behavior of a 390-T6 Al pin sliding against a 1018 carburized steel disc is also examined. To better understand the processes and failure mechanisms of scuffing, the scuffed surfaces and subsurfaces are examined. Based on the experimental observations, a hypothesis and its corresponding criterion for scuffing under starved lubrication conditions are proposed. According to this hypothesis, scuffing is caused by the formation of macroscopic adhesions leading to bulk material failure due to plastic shearing.
Issue Date:1999-01
Publisher:Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign.
Series/Report:Air Conditioning and Refrigeration Center TR-147
Genre:Technical Report
Sponsor:Air Conditioning and Refrigeration Project 82
Date Available in IDEALS:2009-05-22
Identifier in Online Catalog:4221185

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