The scuffing load capacity of lubricants is determined on the FZG gear wheel tension testing machine. A test gear pair with a special tooth geometry runs in the testing lubricating oil according to the immersion lubrication method. The temperature and speed are specified. The load on the tooth flanks is gradually loaded via a lever loaded with weights, which clamps one of the shafts against the other. From load stage 4, the pinion tooth flanks are inspected for any damage after each power stage. Changes are documented. If a defined damage pattern occurs or load stage 12 is reached without the damage pattern occurring, the measurement is completed.
The requirement standard for hydraulic oil (DIN 51524-2 HLP), for example, requires at least load stage 10; the requirement standard for circulating oils (DIN 51517-3 CLP), for example, requires at least load stage 12.
Part 2 of the associated standard (DIN ISO 14635) is geared towards high EP-alloyed lubricating oils. In comparison to the test according to Part 1, a higher peripheral speed and a higher temperature are used.