A comparative study on the performance of cermet and coated carbide inserts in turning of a high-carbon high-silicon cast steel

Abstract Over the past decades, bainitic steels have gained attention for combining high strength and ductility, although these properties often impair machinability. This study investigated the influence of turning parameters on the machining of high-carbon high-silicon cast steel (HC-HSi) in the homogenized condition prior to bainitic transformation. TiN-coated cermet inserts and multilayer TiN/Al₂O₃/TiCN-coated carbide inserts were compared in terms of cutting-force components, surface roughness, chip temperature, and tool wear. Metallographic analysis revealed a fully pearlitic microstructure with refined interlamellar spacing, which may be associated with the alloy composition. Under less severe cutting conditions, the cermet tool produced lower cutting-force components; however, at higher feed rates and cutting speeds, the coated carbide tool exhibited superior performance. Feed rate was the dominant factor affecting surface roughness, whereas differences between tool materials were not statistically significant at the lowest feed rate. Higher chip temperatures for the cermet tool were attributed to its lower thermal conductivity. The coated carbide tool exhibited approximately 43% lower flank wear, probably owing to its multilayer coating and the formation of protective oxide layers. These findings characterize the machinability of HC-HSi cast steel and support the selection of cutting tools and parameters for achieving lower cutting forces, surface roughness, chip temperature, and tool wear.