Tribological performance of plasma nitrided H13 mould steel at elevated temperatures

A nitrided layer was prepared on H13 mould steel by plasma nitriding. The characteristics of obtained nitrided layer were analysed using an ultra-depth of field microscope, atomic force microscope and X-ray diffraction, and the effect of elevated temperature on the wear performance was investigated using a ball-on-disk wear tester. The results show that the nitrided layer is composed of ϵ-Fe 2-3 N and γ′-Fe 4 N phases, which increases the substrate hardness by 111%. The nitrided layer at 800° exhibits superior friction reduction and wear resistance, and the wear mechanism is oxidative wear, which is contributed to the wear-resistant protective layer on the worn track.