INFLUENCE OF SURFACE NANO/ULTRAFINE STRUCTURE ACHIEVED BY DEEP ROLLING PROCESS ON PLASMA NITRIDING AND TRIBOLOGICAL PROPERTIES OF THE AISI ۳۱۶L STAINLESS STEEL

Influence of formation of surface nano/ultrafine structure using deep rolling on plasma nitriding and tribological properties of the AISI ۳۱۶L stainless steel was investigated. Initially, the deep rolling process was carried out on the bar-shaped specimens at ۱۵ cycles with ۰.۲ mm/s longitudinal rate and ۲۲.۴ rpm bar rotation. Then, plasma nitriding treatment was applied on the as-received and deep rolled kinds at ۴۵۰ °C and H۲-۲۵% Vol. N۲ gas mixture for ۵­ h. Surface micro-hardness and un-lubricated pin-on-ring sliding wear tests were carried out on the as-received, deep rolled, plasma nitrided and deep rolled-plasma nitrided kinds. Results revealed that deep rolled-plasma nitrided kind is shown the highest wear resistance than the others, due to the further increased surface hardness achieved via the combined process.

Keywords:

austenitic stainless steel , deep rolling , plasma nitriding , tribological properties.