AAR-942 Elevated Temperature Roll Stability Test
Railroads rely on axel boxes, bearings and other components to function, requiring a lubricating grease of proper consistency. If the grease thins from heat generated by forces (such as those caused by wheel/rail irregularities, roll resonance and rigid body motions), it may compromise grease functionality. This test uses the ASTM D1831 roll stability apparatus to determine changes in penetration numbers caused by combined heating with mechanical stresses. Smaller changes in penetration values indicate a better roll stability.
The original ½ scale worked penetration is determined for the test grease. The grease is then placed in the roll stability apparatus and rolled for 96 hours at 82°C. The resulting grease is again subject to a worked penetration. Reported are the initial, final and change in penetration.