Effect of Active Screen Plasma Nitriding on Fatigue Characteristics of Austenitic Stainless Steel

Abstract

In the active screen plasma nitriding (ASPN) method, the material to be processed is insulated. A mesh-like metal screen is placed around the material to be used as the cathode and a furnace wall is used as the anode. In this study, the effect of ASPN treatment on the fatigue characteristics of austenitic stainless steel was investigated. Nitride layers of varying thicknesses were formed by varying the treatment time to energize the treated material without insulation. A direct-current plasma nitriding apparatus was used for active screen plasma nitriding treatment. The nitriding treatment was performed at an N₂:H₂ concentration ratio of 1:1 for 28.8–172.8 ks at 673 K and 100 Pa. The thickness of the nitride layer increased as the treatment time increased. The fatigue strength increased as a result of the ASPN treatment. Furthermore, the fatigue strength increased as the thickness of the nitride layer increased.

Fig. 7 Rotating bending fatigue tests performed on ASPN-treated round bar samples.