PERFORMANCE-EVALUATING APPARATUS FOR LUBRICANT

PURPOSE:To enable the production of a performance evaluator for a lubricant, by heating a metal material up to a temperature higher than that during a plastic working thereof to cause a plastic deformation thereof. CONSTITUTION:A cylindrical tool 1, the tip of which is precoated with a lubricant is rotated with a drive motor 6. A metal material 3 extracted from a heating furnace 2 is placed on a lower base 4 immediately, a hydraulic cylinder 5 is driven to lift the lower base 4 to bring the material 3 on the lower base 4 into contact with a lower end of the tool 1 under a pressure. The tool 1 is forced into the material 3 while the current rotating force is measured. The rotating force is measured from a motor torque or with a strain gauge applied on a rotating shaft in a rotary driving system of the tool 1. The size of the rotary torque is converted to a friction coefficient, and thus the performance of a lubricant is evaluated from the value of secular changes therein.