EXPLANATION
Thermal stability characterizes physical and chemical property changes that may adversely affect an oil's lubricating performance. This test method evaluates the thermal stability of a hydraulic oil in the presence of copper and steel at 135° C. Rod colors are the evaluation criteria. Sludge values are reported for informational purposes. No correlation of this test with field service has been made.
TEST SUMMARY
A beaker containing the test oil, copper and iron rods are placed in an aluminum block in an electric gravity convection oven for 168 h at a temperature of 135° C. At the end of this time, the copper and steel rods are rated visually for discoloration using the Cincinnati Milacron color chart, and the oil is analyzed for the quantity of sludge.
TEST PRECISION
Where X is the mean value.
The bias of this test method has not been determined.