WEAR BEHAVIOR OF PLASMA-NITRIDED MARTENSITIC STAINLESS-STEEL

The wear behaviour of plasma-nitrided martensitic stainless steel, AISI 440C, has been investigated under various contact conditions including rolling, sliding and combined rolling-sliding, at a wide range of applied loads. It was found that plasma nitriding was effective in improving the wear behaviour of the steel and wear of the nitrided steel occurred in a mild mode under all testing conditions. In contrast to the unnitrided steel which underwent a change from mild wear to severe wear at high bads due to surface and subsurface cracking and shearing, the plasma-nitrided steel did not show such a transition over the load ranges tested. Oxidative and delamination wear dominated the wear process of the nitrided martensitic stainless steel. The short-time nitrided layers exhibited better wear resistance than the long-time nitrided layers produced at similar temperatures.