Effect of nitriding conditions and operation temperatures on dry sliding wear properties of the aluminum extrusion die steel in the industry

Hot work tool steels are widely preferred in the hot extrusion of aluminum alloys. Nitriding of die steels in the aluminum extrusion industry is a well-accepted surface hardening method against surface wear and deformation. In this study, substrate material (DIN 1.2344 steel) is diffusion coated by salt bath nitriding method for 1 h, 2 h, and 3 h. The effect of different nitriding conditions on hardness, tensile and impact properties, wear behavior, and coefficient of friction is studied. Diffusion hardened surface is examined with different characterization techniques. The effect of nitriding time on diffusion layer thickness, tensile properties, impact energy, and wear resistance properties are investigated. It is shown that increasing nitriding time enables thicker diffusion layers that modify the adhesive's wear mechanism to abrasive. Increased nitride layer thickness resisted friction much more compared to less nitrided specimens. On the contrary of wear resistance, tensile properties are reduced due to the diffusion layer’s notch effect. [Display omitted] •Operation temperatures above 500 °C provides an oxidative layer which sensitizes the nitride coating and causes cracks.•For specific wear test temperatures, nitriding process increased the wear resistance and wear rate values are dropped.•The dominant wear characteristics are adhesive, abrasive, tribo-oxidative fatigue wear behaviors for tests.•Thickness of nitride layer does not guarantee wear resistance in the aluminum extrusion process, that is why an optimum nitriding condition should be selected.