Effect of Different Surface Treatments on Resistance to Abrasive Wear of AISI 4140 Steel

The wear resistance of metallic components is fundamental to the efficiency and useful life of mechanical systems subjected to severe conditions, making the evaluation of surface treatments that improve tribological performance essential. In this study, the abrasive wear resistance of AISI 4140 steel was investigated under three conditions: (i) without treatment or coating; (ii) with conventional treatment (quenching and tempering, or carburizing); and (iii) with high‐velocity oxy‐fuel thermal spray coating (AISI 431, Cr ₃ C ₂ –25(Ni20Cr), WC–12Co, and NiCrBSi–50(WC–12Co)). The tests were carried out in a microscale abrasion tester using a tempered SAE 52 100 steel ball and SiC particles as abrasive. The countersamples had dimensions of 30 × 15 × 6 mm. Surface characterization included hardness measurements, profilometry, scanning electron microscopy, and energy‐dispersive X‐ray spectroscopy. The results showed significant reductions in the wear rate for coated surfaces in relation to conventional treatments. The performance of the NiCrBSi–50(WC–12Co) and WC–12Co coatings exhibited the best performance, increasing wear resistance by factors of approximately 13 and 6, respectively. The superior performance of the composite coatings is attributed to a combination of properties, including the compact microstructure, high microhardness, greater adhesive strength, and formation of tribo‐oxides during wear.