EXPLANATION
This test method covers a procedure for determining extreme pressure properties of solid bonded films under high-frequency linear-oscillation motion using the SRV test machine. This laboratory test method can be used to quickly determine extreme pressure properties of parts coated with solid bonded film at selected temperatures specified for use in unlubricated applications where high-speed vibrational or start-stop motions are present with high Hertzian point contact. This test method has found wide application in qualifying solid bonded films used in automotive door lock mechanisms, hinge joints, bolts, and in aerospace. This test method is a material and application oriented approach for characterizing the tribological behavior using random, discrete, and constant parameter combinations. Users of this method should determine whether results correlate with field performance or other applications.
TEST SUMMARY
This test method is performed on an SRV test machine using a steel test ball oscillating against a steel test disk with lubricant between them. The test load is increased in 100-N increments until seizure occurs. The load, immediately prior to the load at which seizure occurs, is measured and reported.
Test frequency, stroke length, temperature, and ball and disk material can be varied to simulate field conditions. The test ball yields point-contact geometry. To obtain line or area contact, test pieces of differing configurations can be substituted for the test balls.
TEST PRECISION
Where X is the average of two results in N.
This method has no bias because the load-carrying capacity can be defined only in terms of this test method.