Abstract: This study conducted milling experiments on steels of different hardness （low-carbon Q235 steel, medium-carbon 45# steel, and quenched-and-tempered 4140 steel） using Ti(C, N)-based cermet end mills. Fixed cutting parameters were employed, and the tool life and wear mechanisms of the cermet tools were systematically analyzed. The cermet tools exhibited excellent wear resistance and long tool life when machining the low-hardness Q235 steel, with wear primarily manifesting as uniform flank wear. When machining the medium-hardness 45# steel, the tools were prone to micro-chipping propagation. When facing the high-hardness 4140 steel, the tools suffered from serrated chipping due to insufficient toughness, resulting in significantly lower tool life compared to cemented carbide tools. This research validates the applicability advantage of cermet tools in high-speed finish machining of low-hardness steels.