TRIBOCORROSION PHENOMENA IN CO- AND FE-BASED HARDFACING ALLOYS EVALUATED USING PIN-IN-ON-DISC WEAR TESTS IN A SIMULATED PWR ENVIRONMENT

摘要

The like-on-like sliding wear behavior of hardfacing alloys Tristelle 5183, RR2450, Stellite 6 and Stellite 3 was investigated at 20 °C and 250 °C using a pin-on-disc apparatus in a simulated PWR environment. Stellite 3 wears considerably less than Stellite 6 at 20 and 250 °C but both exhibit an increase in wear with increasing temperature; the total mass loss increases approximately 20 times. At 20 °C, the iron-based alloys, especially 5183, wear more than the Stellite alloys but both iron-based alloys show a smaller increase in wear with increasing temperature. At 250 °C, Stellite 6, 5183 and RR2450 have statistically similar mass losses post wear testing. Tristelle 5183 does not exhibit a significant increase in wear with respect to increasing temperature whereas the increase in wear for RR2450 is approximately four-fold. In the Stellite alloys, it is the increasing severity of a tribocorrosion mechanism that principally dictates the increase in rate of material removal with respect to increasing temperature. In Tristelle 5183, plasticity dominated wear occurs at 20 °C but at 250 °C the formation of an additional oxide-based tribofilm counteracts other high temperature wear mechanisms. A similar mechanism is also believed to operate in RR2450.