Mechanical and Physical Effect of Nitriding AISI 316L Austenitic Stainless Steel at Various High Temperatures and Different Gas Nitriding Methods

This work investigated the effect of high temperature gas nitriding on AISI 316L to its physical and mechanical properties. In order to modify the surface properties of this material, the samples were treated through gas nitriding at a high temperature of 900˚C hybrid treatment, 1000°C hybrid treatment and 1000°C conventional nitriding method using only nitrogen gas during the heat treatment. These processes have been carried out in a quartz tube furnace for 8hours. The nitrogen, ammonia and methane gases react with the stainless steel to form nitride-layer at its surface. The nitriding results then were analyzed using optical microscopy (OM), Vicker hardness tester, field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD). From the study, it is found that the surface hardness of the nitrided AISI 316L Austenitic Stainless Steel had increased significantly when compared to the unnitrided sample. The hybrid treatment method also was found out to be far better than the conventional nitriding method, where it greatly increased the diffusivity of the nitrogen, thus producing high properties of nitrided layer results.