TRIBOLOGICAL BEHAVIOUR OF PLASMA NITRIDED AND PLASMA SULFONITRIDED COLD WORK STEELS

摘要

Many different nitriding processes have been used for reducing the wear of iron based and non-iron based materials. In the present work, the efficiency of plasma nitriding of cold work steels for reducing wear was investigated. Ball on disc tests were conducted at room temperature and 200°C using austenitic stainless steel balls and different nitrided cold work steel discs. The thickness of both compound and diffusion layer and the composition of the compound layer were varied by changing the plasma nitriding parameters. Wear tracks on the discs and balls were characterised using both SEM and optical profiling. The results show that a thinner nitrided layer reduces wear more efficiently. Higher carbide content seems to be advantageous because the nitrided layer is mechanically better supported.