<p>Hard turning has been considered a sustainable alternative to grinding for hardened steels; however, its adoption is limited by excessive cutting temperatures and rapid tool wear, particularly when cubic boron nitride (<i>CBN</i>) and conventional ceramic inserts are used at speeds above 200&#xa0;m/min. These constraints reduce the feasibility of dry machining in processing hard-to-machine alloys such as AISI D3 tool steel. This study evaluates the performance of titanium nitride (TiN)-coated hybrid ceramic inserts (Al₂O₃ + Ti(C, N)) for dry turning of hardened AISI D3 steel. A Taguchi L25 orthogonal array was employed to systematically analyze the effects of cutting speed, feed rate, and depth of cut on cutting force, surface roughness, and material removal rate (<i>MRR</i>). Multi-response optimization was performed using grey relational analysis (<i>GRA</i>) to identify an optimal cutting regime. The optimal parameters—cutting speed of 192&#xa0;m/min, feed rate of 0.05&#xa0;mm/rev, and depth of cut of 0.50&#xa0;mm—yielded a 19.6% reduction in cutting force, a 23.4% improvement in surface finish, and a 17.8% increase in <i>MRR</i>. These results validate TiN-coated ceramics as efficient, cost-effective, and environmentally sustainable substitutes for grinding, providing a practical pathway to enhance productivity and surface quality in hardened steel machining.</p> Graphical Abstract <p></p>