Applications of Four-ball Testers in Evaluation of Liquid Lubricants

The applications of four-ball testers in lubricity evaluation of liquid lubricants were summarized, the roles of four-ball testers in friction, abrasion, and extreme-pressure properties tests of lubricating oil and lubricating grease were introduced, and the advantages and disadvantages of four-ball tester method were analyzed. The improvement measures were discussed at last.