4 Ball Wear Tester

Automatic Loading, Inline Torque For EP, Wear  studies of Grease, Oil, Lubricants

4 Ball Wear Tester to study EP and wear properties of oil , lubricant and greases

Main Features

The 4 ball wear tester machine is used to study grease, lubricants and oil for EP and wear tests. The same tester can be used for several standard test such as ASTM D2266, D4172, ASTM D2596, ASTM D2783, BS EN ISO 20623, BS ISO 26422, CEC L-45-A-99, DIN 51 350, IP 23.

It measures inline torque, temperature , down force, total wear, acoustic emissions at all times. Currently used by several Fortune 500 firms globally. 

Module Features
● Programmable Close loop Force upto 12,000N
● -60C to 250C (500c) Temperature
● Both EP and Wear
● Inline Torque, Acoustic, Force, Temperature
● ASTM, DIN, ISO Compliant 

Platform Introduction


The state of the art Rtec Multi Function tribometer Mft-5000 is globally regarded as the most versatile and technologically advanced tribometer.  The patented integrated 3D profilometer allows to analyse surface change vs time makes it usable for many application across various industries. In addition it comes with patented force sensors (piezo, capacitive & strain gauge) with ultra low resolution, highest speeds, stable torque and widest load range than any other commercially available tribometer. 

MFT-5000 verstatily allows to mount several test/application specific modules on same platform. Please visit following links to learn more -  Lubricant Summary Page, Product pageMain Applications

Detailed Module Information

The 4 ball tribometer Module is used to study extreme pressure EP, coefficient of friction, load wear index, ball weld point, wear preventive additives for lubricating grease, oil and additives. 

Wear Preventive Test – This test is used to evaluate lubrication performance of grease or oil. The test is carried out at relatively mild test conditions e.g. 392N at 75C at 1200 rpm for 1 hour. Tests with higher loads, and longer duration can also be designed. 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 is 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 wear test as the down force is precisely controlled in real time.

Extreme Pressure EP Test – The 4 ball ep test test is used to test lubrication properties of lubricants (oils and greases) under extreme pressure conditions. The top ball is rotated at high speeds and high loads for a short duration of time e.g. 1800 RPM, 3000N and 30s. Load is increased in steps or linearly until the lubricant fails. The maximum load that can be applied is up to 12,000 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. The 4-ball tester gives high reproducible results are forces are precisely maintained during the test.

Data and Analysis

Rtec 4 Ball Tester data

Figure shows results of an increasing load test. The test was configured to automatically apply a linearly increasing load from 400N to 4000N at a rate of 600N/minute. The acoustic signal was also recorded. It shows that the sample started to fail around 2800N, while complete failure leading to welding was observed at around 3600N. The inset in the figure shows the welded lower balls after failure occurred in the extreme pressure tests. During the test coefficient of friction was measured in real time and recorded with high precision.

4 ball wear test  ball scar 3D data using Rtec 4 ball wear tester and integrated profilometer

Figure shows the 3D Image of the ball shows size or scar on one of the lower rotating balls after running a 4 Ball wear test for 1 hour at 1200rpm and 392N. The 3D Image was created using Rtec Universal Profilometer. The profilometer shows both volume wear loss and scar diameter or rotating or stationary balls creating using various test methods.


MFT-5000 4-ball tester for lubricant or grease test is an excellent option to run multiple 4-ball tester standard and several customized tests on the same platform. High loads up to 12,000N can be applied to evaluate the lubrication and extreme pressure properties of modern lubricants and additives. The temperature can be controlled and monitored in real time. The acoustic data is also recorded to determine the onset of failure before complete failure as indicated by welding or smoke. The anti-splash containers allows to run these tests without spills and splashes. 


ASTM D2596, ASTM D2783, ASTM D2266, ASTM D4172

Contact us to learn more