Force modeling and experimental investigations on machinability of SDSS 2507 under dry turning conditions using CVD TiCN-Al2O3 coated tools

Abstract

Super Duplex Stainless Steels (SDSS), in spite of their numerous commercial applications is considered to be extremely difficult to machine owing to its poor thermal conductivity, severe chemical affinity, and work hardening nature. Several studies have analysed the possibility of adopting conventional lubrication/cooling methods and coating techniques to address the machinability-related challenges of the alloy. However, limited studies have explored the use of multi-layered coatings to enhance the tool life properties while machining the alloy. Hence, this work intends to investigate the impact of using CVD TiCN-Al₂O₃ coated tools to analyse the significance of parameters like speed, feed rate, and depth of cut on the machinability aspects of SDSS 2507 in dry turning conditions. The experimentation analysis revealed that while speed, feed rate, and depth of cut had a significant impact on influencing the tool wear characteristics, surface roughness values were impacted by only feed rate values. Similarly, feed rate, depth of cut, and interaction effects between these factors were noted to have a considerable influence on the cutting forces. Meanwhile, the study also focuses on developing an analytical model to predict the cutting forces that consider the sticking-sliding effects by incorporating the chip groove area across the machining interface. The predicted cutting force values were observed to be in close agreement with the experimental results. The error values were noted to be below 15% in the majority of the cases, which confirms the significance of the predicted model.