ASTM D2266 Wear Preventative Characteristics of Lubricating Grease (Four Ball Method)
ASTM D4172 Wear Preventative Characteristics of Lubricating Fluid (Four-Ball Method)
Lubricants intended for use with moving steel parts normally contain compounds to inhibit damage to rubbing metal, giving the lubricant its wear preventative characteristics. Although this test is designed to compare lubricants in steel-on-steel applications, we are able to test other metals, such as bronze, at your request. Use ASTM D2266 for grease and ASTM D4172 for oils.
In the early 1980s Petro-Lubricant Testing Labs developed a method to determine the coefficient of friction during this test. Using a computer-enhanced data collection system, the progression of the test is followed and a time versus coefficient of friction graph is generated. Our clients find this to be an extremely useful tool in evaluating their lubricants.
In this test, three steel balls are arranged in a circle, locked in place and coated with the test lubricant. A forth ball is placed on top, in the center of the three balls. The system is heated, load is applied and the top ball is spun at 1200 revolutions-per-minute. The three lower balls are removed, cleaned and examined under a microscope. The scars resulting from sliding against the top ball are measured. The average size of the scars is reported in millimeters.
When requesting this test, please let us know if you would like any modifications from the ASTM method, including changes to temperature, time, speed, load or metal.