Study of microhardness and structure of tool steels after ion-plasma nitriding in a glow discharge

Abstract

In this paper, the effect of ion-plasma nitriding (IPA) on the microhardness and structure of tool steels is investigated. Samples of HSS M2 and P18 steels, quenched at 1300°Cand then tempered three times at 550°C, were used for the study. The IPA was carried out in a gas mixture consisting of 50% argon, 35% nitrogen and 15% hydrogen at a pressure of 250 Pa and a surface temperature of 400°C, 500°C and 600°C for 3h, 6h and 9h, 9 h. It was found that the highest surface hardness of 1600 HV for HSS M2 steel specimens and 1500 HV for P18 steel specimens were observed after IPA in TR at 500°Cfor 9 h. The maximum hardened layer depth of 120 μm for HSS M2 specimen and 100 μm for P18 specimen were observed after treatment at the same temperature for 6 and 9 hours