4-Ball Wear Tester

Rtec Four ball tester with Automatic Loading, In-line Torque For EP, Wear Studies of Grease, Oil, Lubricants

Upper rotary drive for tribology tests

Detailed Module Information

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4-ball tester setup on MFT-5000 tribometer

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.

Data from 4-ball wear test using automatic loading
Figure 1

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.

Ball scar image using rtec 3D microscope
Figure 2

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.

Solution To

The 4 Ball Tester is used extensively across a wide range of industries:

  • Additives
  • Lubricants
  • Grease
  • Additives
Universal tribometer MFT-5000 by Rtec Instruments

The MFT-5000 Has More To Offer

Take a closer look at the Multi Function Tribometer.

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