Multiple Standard Tests
ASTM D2266, D4172, ASTM D2596, ASTM D2783, BS EN ISO 20623, BS ISO 26422, CEC L-45-A-99, DIN 51 350, IP 23.
Wear Protective Test
This test evaluates lubrication performance of grease or oil. The test is carried out at relatively mild test conditions. For example, 392 N at 75°C at 1200 rpm for 1 hour. The performance of the lubricant is evaluated by measuring and comparing the wear diameter of the balls after the test. Diameter of wear scar on each of the three lower balls are measured at two locations 90° to each other. The average of six measurements is reported as wear diameter for the 4 ball test. The four ball testing machine gives high reproducible results during the wear test as the down force is precisely controlled in real-time.
Extreme Pressure EP Test
The 4 ball EP test is used to test lubrication properties of lubricants (oils and greases) under extreme pressure conditions. The top ball rotates at high speeds and high loads for a short duration of time. For example, 1800 RPM, 3000N and 30s. Load increase in steps or linearly until the lubricant fails. The maximum load available is up to 10,000 N. The failure is determined by welding of the four balls, visible smoke, instantaneous increase in friction or torque. The test is automatically stopped at the onset of failure. The lubricants are rated based on their ability to “pass” the test without failure at applied loads.
Data and Analysis
Quick screening test to evaluate extreme pressure properties.
Figure 1 shows results of an increasing load test. The test was configured to apply a linearly increasing load from 400 N to 4000 N. The acoustic signal shows that the sample began to fail around 2800 N. Complete failure leading to welding observed at around 3600N. During the test, coefficient of friction was measured in real-time and recorded with high precision.
Figure 2 shows the 3D Image of the ball scar. The Rtec Universal Profilometer created the 3D Image. The profilometer shows both volume wear loss and scar diameter or rotating or stationary balls creating using various test methods.
The 4 Ball Tester is used extensively across a wide range of industries: