Improvement of surface and tribological properties of EN8 EN24 and EN41B Steel by active screen Plasma Nitriding

Abstract

EN8, EN24, and EN41B materials have multiple applications in various industries. One of the possible ways to improve the surface properties of these materials is through plasma nitriding, which is metallurgically flexible and offers exceptional dimensional control and surface finish. Active Screen Plasma Nitriding (AS_PN) is known to be the most efficient method of plasma nitriding, which eliminates the disadvantage like the edge effect and hollow cathode effect associated with conventional plasma nitriding. Hence, in this study, AS_PN treatment is carried out on EN8, EN24, and EN41B steel samples at the treatment temperatures of 500and#730;C and 550and#730;C newlinefor treatment times of 2 hr, 4 hr, and 6 hr using a gas mixture ratio of and#119867;2/and#119873;2 = 4:1 at a chamber pressure 1.2 mbar using floating potential. newlineFrom the analysis of AS_PN treated EN8 samples, it is realized that the samples gain newlineweight as the treatment temperature and time increase. The maximum weight gain is achieved newlinewhen the sample is treated for 6 hr at 550and#730;C. The cross-sectional SEM image of the AS_PN newlinetreated EN8 samples show the variation in the compound layer from 8.646 microns to 16.354 newlinemicrons for the treatment temperature of 500and#730;C and treatment time of 2 hr to 6 hr. Whereas, for 550and#730;C treatment temperature and treatment time of 2 hr to 6 hr, the improved compound layer is 18.363 microns to 24.58 microns. XRD analysis performed on AS_PN treated EN8 newlinesamples reveals the formation of compounds like and#947;and#8242; and#8722; and#119865;and#119890;4and#119873; and and#603; and#8722; and#119865;and#119890;2and#8722;3and#119873; phase. The newlinemicrohardness test shows that the AS_PN treated EN8 sample at 500and#730;C for 4 hr had the highest surface hardness of 3.4 times its base material. The weight loss during the wear test highlights newlinethe improvement in wear resistance on treated EN8 samples by the AS_PN process. Further, newlinethe highest improvement in wear resistance of the EN8 sample is seen for treatment at 500and#730;C newlinefor 6 hr.