Multi-response optimization and modeling of machinability indicators in the turning of duplex stainless steel

Duplex stainless steels have a two-phase microstructure containing both ferritic and austenitic phases and have high strength, hardness, and corrosion resistance. However, these properties complicate chip formation during machining and make chip control difficult. Lack of chip control during the turning process negatively affects machining efficiency, quality, and safety. Inadequate chip control results in an inability to manage unwanted chip formation, especially long and tangled chips. This affects both machine operations and workpiece quality. Therefore, machining parameters need to be optimized and carefully examined to ensure chip control. The objective of this study was to detect the optimal combination of processing parameters for decreasing cutting force and surface roughness throughout the turning of AISI 2205 duplex stainless steel. To attain this goal, the experiments used the Taguchi L18 orthogonal array experimental design. Two distinct chip breaker forms of cemented carbide cutting inserts (NR4, NM4), three distinct feed rates (0.1–0.2–0.3 mm/rev), and three distinct cutting speed (180–210–240 m/min) values were used as machining parameters. As a consequence of the study, the lowest cutting force and surface roughness were obtained at NR4 insert, 0.1 mm/rev feed rate and, 210 m/min cutting speed. Using the entropy weighted-TOPSIS approach, a multi-objective optimization process was carried out for surface roughness and cutting force. As a result of the optimization approach, the sequence of experiments in which the most suitable processing parameters were obtained was determined. Anova study shows that feed rate is the most efficient parameter for both surface roughness and cutting force. To forecast processing outputs, mathematical models were constructed utilizing the response surface method. In summary, the findings from this study can contribute to the improvement of the productivity required by the industry in turning AISI 2205 duplex stainless steel. © The Author(s), under exclusive licence to The Brazilian Society of Mechanical Sciences and Engineering 2024.