The method according to this standard gives information about the thermal stability of hydraulic oils.
Brief description of the method
Clean, polished, preweighed copper and steel rods are placed in a 250 ml beaker, which contains 200 ml of the oil sample. It is imperative that the rods are completely below the surface of the oil and in contact with each other. The samples are placed in an electric oven at 135°C for 168 hours. After cooling to room temperature, the following tests are carried out:
- neutralisation number
- metal loss after cleaning with potassium cyanid
- metal loss after cleaning with sodium hydroxide