1 Summary of Test Method
The four steel balls in the four-ball tester are arranged as equilateral tetrahedron. The upper ball rotates under 1400~1500shift/min. The three balls at the lower place shall be fixed together with an oil box, in this way, the steel balls are applied with load from bottom to top by means of lever or hydraulic system. During the test process, the contact points of four steel balls shall be immersed in the lubricant. The wear scar diameter of all balls in the oil box shall be measured after the test which lasts 10 seconds for each. The test shall be repeated according to specified procedures till the assessment index of load-carrying capacity of representative lubricant is worked out.
Contents
1 Summary of Test Method
2 Definitions
3 Apparatus and Materials
4 Reagents
5 Preparation Works
6 Test Procedures
7 Calculation and Report
8 Precision
Appendix A Accuracy Inspection for Four-ball Tester (Additional)
Appendix B Determination Method Example for Load-carrying Capacity of Lubricant (Informative)
Additional Explanation
