Lubricants
What is it?
The Four Ball machine provides an evaluation of the anti-wear and extreme pressure properties of fluid lubricants and greases in sliding contacts.
Why do we use it?
This machine is broadly used, mainly to demonstrate performance within industrial applications like greases. The ASTM standard tests are well known in the industry and used as a reference by many lubricant formulators.
How does it work?
A ball, mounted in a chuck, is rotated against three stationary balls in a pot containing the sample lubricant.
Typical Test Conditions
Parameter : Value
- Speed : 1200 or 1700 rpm
- Temperature : Ambient to 200°C
- Load : 40 to 800 kgF
- Standard Specimens : 4 x 12.7 mm diameter balls
- ASTM D2266 : Anti-wear
- ASTM D4172 : Anti-wear
- ASTM D2596 : Extreme pressure
- ASTM D2783 : Extreme pressure
Test Parameters
In ASTM D2266 and ASTM D4172 test parameters, the anti-wear properties of a lubricant are evaluated. For this, the diameters of the wear scars that occur on the stationary balls are measured after the test.
For a given load, the smaller the wear scar diameter, the better the load-carrying properties of the fluid.
In the ASTM D2596 and ASTM D2783, the extreme pressure properties of the lubricant are evaluated by generating the Load Wear Index and the Weld Point.