The Influence of Nitriding Time of AISI 316L Stainless Steel on Microstructure and Tribological Properties

An investigation on microstructure and tribological properties of low temperature nitriding on 316L austenitic stainless steel with varies time treatment has been made in the present work. The improvement of wear resistance and surface hardness of nitrided steel were identified related with the increasing of layer thickness due to the extended time of treatment, where the hardness significantly improved with 754 Hv0.01 after 8 h treatment as well as the tribological properties. The nitrided layer properties improvement in this investigation shows that the wear mechanism was confirmed by the results of coefficient of friction measurements that were obtained from pin on-disc wear test ranging averagely from 0.3-0.5 on 8 h nitrided sample compared to untreated (1.4-2.0) and 2-5 N (0.6-0.8) with shorter nitrided time, respectively. This is agree with theoretical approach where minimum value is achieved and represents high wear resistance. Surface morphology were characterized by using FESEM and the micrograph of worn region showed that untreated 316L experienced severe wear, while nitrided steel presented only slight abrasion with shallow and narrower wear track.