Effect of nitrided-layer microstructure control on wear behavior of AISI H13 hot work die steel

Abstract Gas nitriding has become a popular thermo-chemical surface treatment, which is being used to develop thermal/mechanical fatigue and wear characteristics of iron and steels. In this study, the gas nitriding of AISI H13 hot work die steel was carried out in flowing NH 3 gas at 550 °C for 5–15 h. By adjusting the nitrogen potential ranging from 0.18 to 2.8, three types of nitrided surface layer consisting of e-Fe 2-3 N and γ′-Fe 4 N phases, γ′-Fe 4 N single-phase, as well as the α-(Fe, N) phase had been prepared, respectively. The corresponding microstructure, hardness and thickness of the nitrided layer were systematically characterized. A contrastive analysis of influence of nitrided-layer microstructure control on wear behavior of AISI H13 hot work die steel was conducted. The nitrided surface layer consisting of e-Fe 2-3 N and γ′-Fe 4 N phases showed excellent wear resistance under loads of 100 N but poor wear properties at 300 N. The wear mechanism was revealed based on the microstructure characteristics, surface hardness and toughness of each nitrided surface layer.