Scuffing failure in heavily loaded slow speed conformal sliding contacts

Scuffing failure phenomenon is studied experimentally in heavily loaded slow speed conformal sliding contacts of two flat thrust washers in a regime close to boundary lubricated condition. Lubricants used are base oils of pure mineral oil and poly-α-olefin (PAO). Speed range is 0.76-33.0 cm/s. Material studied is hardened 52100 steel for both washers in contact. Scuffing threshold load at failure, friction, and surface bulk temperature are major data measured. The surface total temperature is determined with the measure bulk temperature in addition to the surface flash temperature calculated using Jaeger’s theory. Characteristic scuff ing failure mechanisms are categorized in terms of various speed ranges. A simple model is proposed to predict scuffing failure based on theories in adsorption/desorption dominated lubricated wear and metal oxide formation kinetics. Good agreement is found between experimental data and theoretical prediction in terms of threshold load in certain speed range.