Wear Behavior on the Nitrided Steels

The plasma nitriding technique is applied to explore a new technology for preparing dual phase nitrogen steels. The holding temperature was varied from 823 K to 853 K. Japan Industrial Standard (JIS) steels of SCM415 and SCM435 were employed for substrate. X-ray diffraction technique is carried out to identify phase and structure after each nitriding. Scanning electron microscope is also applied to observe microstructure of nitrided layer on the cross section of the specimens. Micro-Vickers hardness tester is also used to measure the hardness profile on the specimen cross section. The dual phases, which are consisted of austenite phase and ferrite phase, are detected by XRD up to [15 μm from the specimen surface. Surface hardness on the dual phases nitrided steel reaches at about Hv500, and the surface hardness of the nitrided SCM415 reaches at around Hv800. These facts indicate that there are many possibilities to strengthen austenitic phase by quenching after re-heating, to prepare dual phase steels with the reduced amount of alloying elements and to be interested in crystallography.