Developed by the American Society for Testing and Materials (ASTM), the ASTM D4290-20 standard provides a test method for evaluating the leaking tendencies of wheel bearing greases when tested under prescribed conditions.
This test method distinguishes between wheel bearing greases with markedly different high temperature leakage characteristics. It is not the equivalent of long-term service tests. This test method has proven helpful in screening greases for leak trends for automotive wheel bearing applications.
The leak trends tester is used to evaluate the tendency of automotive wheel bearing grease to separate oil or grease under anticipated laboratory conditions. This test is performed at high temperature in a modified automotive spindle-hub assembly that is rotated at 660 rpm. Any oil or grease leaks are collected and weighed during the test period.
Automobile wheel bearings are exposed to high loads, high speeds and high temperatures. Long-term efficient bearings require a grease that is resistant to mechanical and thermal changes, and that does not separate, collapse, soften or leak. Grease must also resist the formation of sludge, varnish, gum and varnish.
This test method utilizes a specially designed hub bearing assembly. A standard amount of test grease is filled into the inner and outer tapered roller bearing cones. A quantity of standard grease is then added to the hub, and the unit is assembled according to the method. Subsequently, a thrust load is applied, the shaft speed and temperature are adjusted, and the bearings are allowed to rotate for a predetermined time. The amount of grease and oil that drips from the assembly is then measured. Observations regarding the condition of the grease, such as the presence of gum, varnish, or lacquer-like material, are reported.
Briefly, the test method described in the ASTM D4290-20 standard involves evaluating the leakage tendencies of wheel bearing greases when tested under prescribed conditions.
Our organization, among the numerous test, measurement, analysis and evaluation studies it provides for businesses in various sectors, also provides standard testing services for determining the leakage trends of automotive wheel bearing grease in accelerated conditions within the scope of ASTM D4290 standard, with its trained and expert staff and advanced technological equipment.
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