Study of the mechanical and tribological behaviour of a low-alloy steel treated by nitriding

This study investigates the effects of plasma nitriding treatment on the mechanical surface properties of 25Cr2Ni4W low alloy steel, using Charpy test specimens. Plasma nitriding is a surface modification process that introduces nitrogen into the steel, enhancing its hardness and wear resistance. The experimental setup involved a comparative analysis of treated and untreated specimens to evaluate the impact of the nitriding process on the material’s mechanical performance.Optical microscopy (OM) analysis of the nitrided specimen revealed the formation of a nitride zone at the surface, confirming successful nitrogen implantation. The Charpy impact test showed that the treated specimen required 72.8 Joules of energy to fracture, a significant increase of 10.3 Joules compared to the untreated specimen, which required only 62.5 Joules. This indicates that plasma nitriding improved the material’s toughness and resistance to crack propagation. Additionally, the nitriding process led to an increase in nano-hardness, as measured using nanoindentation techniques. The treated specimen exhibited a higher surface hardness compared to the untreated sample, further enhancing its wear resistance and durability. These results suggest that plasma nitriding effectively improves both the hardness and toughness of 25Cr2Ni4W low alloy steel, making it a promising treatment for applications requiring enhanced mechanical performance, particularly in high-stress environments.