Extreme pressure performance of lubricating oil has three main evaluation indicators, including maximum card load PB-free, comprehensive wear ZMZ and sintered load PD. Usually determined by four ball method.

No card load PB

Under the test conditions, test ball has the highest bite card load is called a load. It represents the lubricating oil film strength.

Integrated wear ZWZ

Under the test conditions, before sintering logarithmic unit of 0.1 per cent power to three on a stationary ball, ten test calibration load average. It represents the lubricant in the load to minimize wear under extreme pressure resistance capacity index.

Sintered load PD

Under the test conditions, rotate the ball and following three static sphere sintering of the minimum load. It represents had exceeded ultimate load carrying capacity of lubricating oil. Under high load, boundary lubrication conditions of lubricant (agent), such as cutting oils and rolling oils, extreme pressure gear oil, extreme pressure performance of oil products is a very important use of performance indicators. Usually require extreme pressure anti-wear agents and lubricity additives to improve oil extreme pressure properties.