ASTM D2070 Standard Test Method for Thermal Stability of Hydraulic Oils
3. Summary of Test Method
3.1 A beaker containing test oil, copper and iron rods is placed in an aluminum block in an electric gravity convection oven for 168 h at a test temperature of 135°C. At the completion of the test, the copper and steel rods are rated visually for discoloration and the oil is analyzed for the quantity of sludge.
4. Significance and Use
4.1 Thermal stability characterizes physical and chemical property changes which 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 the test to field service has been made.
