Performance of multilayer coated tool in dry machining of AISI 316 austenitic stainless steel

Abstract

The recent advance in coating for cutting tool has significantly improved the machining performance in terms of tool life, machined surface quality and productivity. Multilayer coating synergize the advantage of different coating materials in the layered structure and has particular edge over monolayer coated tool. Austenitic stainless steel is one of the most important grades of stainless steel as it has a variety of engineering applications particularly when resistance to corrosion is a primary requirement. However, low thermal conductivity and work hardening characteristics have made it difficult to machine with conventional cutting tools under normal operating condition. Therefore in the present study, attempt was made to study the machinabilty of AISI 316 grade austenitic stainless steel with a commercially available multilayer coated cemented carbide turning insert. The multilayer coating consists of TiN-TiCN-Al2O3-ZrCN coating. The substrate and multilayer coating composition has excellent combination of hardness and toughness and the top coat of ZrCN has auto friction property. In the present study, the effect of cutting speed was studied on the dry machining performance of AISI 316 grade austenitic stainless steel in terms of tool wear(average flank wear) and chip characteristics(types & colour of chip, macro morphology and chip thickness). The study clearly indicates as the cutting speed increased from 100 to 200 m/min average flank wear increased for a particular machining duration. Consequently, tool life was also found to be maximum for Vc = 100 m/min while rapid progression of tool wear was observed for dry machining of Vc = 200 m/min. the increase in cutting speed also results in decrease in chip thickness and chip radius. Therefore the current study demonstrated the potential of multilayer coated cemented carbide insert in dry machining of AISI 316 austenitic stainless steel.