High-Temperature Friction and Wear of Boron Steel and Tool Steel in Open and Closed Tribosystems

More and more components in automotive, material processing, and mining industries are operating under harsh conditions involving high temperatures and high contact pressures. Tribotesting for such applications is done using both open (one surface meeting a fresh countersurface) and closed (one surface follows the same track on the countersurface) test configurations. In order to enable development of new materials and processes intended for such conditions, there is a need for better understanding pertaining to tribological phenomena occurring under these different test configurations.In this work, friction and wear characteristics of quenched and tempered tool steel sliding against boron steel (22MnB5) have been studied. The experiments were conducted using a specially designed hot strip tribometer (HST) under dry conditions at room temperature and 400 degrees C in open as well as closed configurations. Scanning electron microscopy/energy-dispersive spectroscopy, and X-ray techniques were carried out to analyze the worn surfaces. Additionally, the results from the closed test configuration were compared to previous tests carried out with the same materials and parameters using a pin-on-disk (POD) test rig. The results have shown that wear was reduced at higher temperatures as well as with repeated sliding on the same contacting surfaces (i.e., closed configuration) compared to those with an open configuration. A good correlation of wear mechanisms and coefficient of friction between closed configuration tests and those carried out with the POD test rig were observed especially at 400 degrees C.