Description

The ST-PR Pitting Rig features a three-disc-on-roller configuration designed to investigate RCF failure mechanisms, including macro and micro pitting in rolling-sliding contacts under both dry and lubricated conditions.

The test roller specimen is driven by a single motor, utilizing a circulating torque mechanism with gear pairs, which eliminates the need for high-capacity drive motors. Different Slide Roll Ratios (SRR) are achieved by selecting the appropriate gear pairs and/or varying the diameters of the discs and test roller.

Load is applied via a manually adjusted pneumatic cylinder action on the top disc, which is mounted on a floating shaft. A precision pressure transducer is used to indicate the load, which is then transmitted to the test roller, which is also mounted on a floating shaft. Finally, the load on the test roller is transmitted to the lower discs, which are mounted on fixed shafts.
A load cell reacts the horizontal force acting on the upper disc, which is generated by traction between the test roller and the upper disc.
The two lower discs are electrical insulated and fitted with brushes, allowing electrical contact measurements between each disc, through the contacts with the roller specimen.

Test Configurations

Various disc and test roller geometries can be used to achieve different Hertzian contact pressures and slide-roll ratios. Test speeds are controlled through a high-speed motor spindle with a frequency inverter to achieve the desired surface velocity of the discs and rollers. The test temperature is regulated via a lubrication circulation system with a temperature-controlled feedback mechanism.

Typical Results