This test method can be used to determine wear properties and coefficient of friction of lubricating greases at selected temperatures and loads specified for use in applications where high-speed vibrational or start-stop motions are present for extended periods of time under initial high Hertzian point contact pressures. This test method has found application in qualifying lubricating greases used in constant velocity joints of front-wheel-drive automobiles and for lubricating greases used in roller bearings. Users of this test method should determine whether results correlate with field performance or other applications.
1.1 This test method covers a procedure for determining a lubricating grease's coefficient of friction and its ability to protect against wear when subjected to high-frequency, linear-oscillation motion using an SRV test machine at a test load of 200 N, frequency of 50 Hz, stroke amplitude of 1.00 mm, duration of 2 h, and temperature within the range of the test machine, specifically, ambient to 280°C. Other test loads (10 to 1200 N for SRVI-model, 10 to 1400 N for SRVII-model, and 10 to 2000 N for SRVIII-model), frequencies (5 to 500 Hz) and stroke amplitudes (0.1 up to 4.0 mm) can be used, if specified. The precision of this test method is based on the stated parameters and test temperatures of 50 and 80°C. Average wear scar dimensions on ball and coefficient of friction are determined and reported.
Note 18212;Optimol Instruments supplies an upgrade kit to allow SRVI/II-machines to operate with 1600 N, if needed.
1.2 This test method can also be used for determining a fluid lubricant's ability to protect against wear and its coefficient of friction under similar test conditions.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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