Sliding wear test methods

The wear achieved from a sliding wear test is in the form of an annulus on the top ball and a worn circle on each of the lower three balls. A standard method of assessing the severity of wear is to measure the wear scar diameters of the lower balls and examine how this varies with increasing load. It can be seen from Figure 5 there was a sudden transformation in the wear regime at the 110 kg load. This is known as the transition region, in which the wear behaviour below is known as mild wear and above as severe wear. When the contact experiences mild wear the oil film between the contacts is intact and mainly elasto-hydrodynamic lubrication is present. When severe wear occurs, the... 

Organization for Economic Cooperation and Development, Group on Wear of Engineering Materials, Wear during Sliding Comparison of Test Methods, Technical Secretariat c/o Metal Research Institute TNO, Delft, The Netherlands, 1967. 

As with other mechanical properties there are standard tests to measure wear resistance. The main method is described in ASTM G99, which uses a pin-on-disk apparatus. This test is used to measure sliding wear of ceranucs and ceramic coatings. 

Wear tests were carried out at room temperature imder dry condition. Normal load values of 0.98, 1.96, 2.94, 3.92, and 4.9 N were used. Sliding velocity was fixed at 0.02 m/s, and the sliding distance was 120 mm. Wear of the pin was measured by a gravimetric method using an electronic balance at a 0.0001 g precision. Each worn surface was measured with a profilometer after the wear test to obtain profiles normal to the direction of friction. The profiles were used to calculate the wear rate. The wear rate, w, is defined as w = V/L, where V is the wear volume and L is the sliding distance. Each point of the diagrams from the experimental results is an average of five tests and measiu-ements. 

G77 Test Method for Ranking Resistance of Materials to Sliding Wear Using Block-on-Ring Wear Test (vol. 3.02, p. 302-315, 1995)... 

Table 11.9 summarizes the friction and wear characteristics of several polymers sliding on steel (80). The PV limit is the product of the normal pressure and the relative surface velocity. The PV limit is used to define the onset of catastrophic failure of the material resulting from mechanical degradation by frictional heating. The test method of preference is based on the theory that the wear coefficient is practically constant below the limiting PV. Thus, a plot of the wear coefficient vs. load at constant speed defines PV by establishing... 

G 133 Test Method for Linearly Reciprocating Ball-on-Flat Sliding Wear Ball wear scar diameter, flat profile... 

Pressure (MPa) Sliding Velocity (m/min) PV(MPa m/min) Test Method Coefficient of Friction, Static Coefficient of Friction, Kinetic Wear Factor, K [10 mmV (N m)] Wear Factor, K, Mating Surface [10 mmV(N m)]... 

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