ASTM d2783, DIN 51350, JIS k2519, IP 239, USSR 9490-75.
Detailed explanation of Pb value required by lubricant bearing capacity standard
Pb (PB) value: the maximum non seizure load (kg), the maximum load (kg) without seizure under the test conditions, which represents the oil film strength, that is, when Pb, the wear mark diameter under the maximum non seizure load shall not be greater than 5% of the wear mark diameter (i.e. compensation diameter) on the corresponding compensation line. If the measured wear mark diameter under a certain load is 5% greater than the wear mark diameter on the corresponding compensation line, The next test shall be carried out under a lower load and continue this operation until the maximum non seizure load is determined.
SH120 automatic four ball machine lubricant bearing capacity test is in the form of sliding friction. Under the condition of extremely high point contact pressure, it is mainly used to evaluate the bearing capacity of lubricant. It includes three indexes: maximum non seizure load Pb, sintering load Pd and comprehensive wear value zmz. In practical application, different evaluation indexes can be selected according to various uses of lubricants. The four ball friction testing machine can also do long-term wear resistance test of lubricant, measure friction coefficient and record friction and temperature curve.
For example, the wear mark diameter of an oil measured under the load of 80kg is 0.47mm. Look up table 1 and know that the compensation diameter at 80kg is 0.44mm, then it can be concluded that the Pb value of the oil is less than 80kg, which needs to be retested with the weight of small load. (it is calculated that 5% of 0.44 = 0.022.0.47-0.44 = 0.03 is greater than 5% of the diameter. It is necessary to reduce the load and test the Pb value again.)