Performance of an aminolyzed castor oil emulsion as a cutting fluid in the MQL turning of ASTM A182 F55 super duplex stainless steel

Global demand for manufacturing processes aligned with cleaner practices has increased interest in vegetable-based oils (biolubricants) as eco-friendly alternatives to petroleum-based oils. In this context, a novel vegetable emulsion was proposed as a cutting fluid in a turning process. This emulsion was formulated with 1 wt% aminolyzed castor oil (ACO) and 99 wt% water. ASTM A182 F55 super duplex stainless steel was selected as the workpiece because of its high work-hardening rate, high ductility, and low thermal conductivity result in low machinability, opening new research opportunities in the field of machining. Three cutting conditions were used in the turning process: dry cutting (DRY), Minimum Quantity Lubrication (MQL) with a semi-synthetic emulsion (SS-MQL), and MQL with an ACO emulsion (V-MQL). The experiments were conducted using TiAlN-coated carbide cutting tools. The results of V-MQL exhibited the lowest tool wear among the cutting conditions due to the formation of a protective film promoted by the ACO emulsion, which was adsorbed on the tool’s surface. Regarding chip formation, the DRY condition produced long and tangled chips with larger saw-tooth spacing. In contrast, both MQL conditions generated shorter chips with smaller saw-tooth spacing due to the cooling effect of the emulsions. Additionally, V-MQL promoted the highest chip work hardening, followed by SS-MQL and DRY. All cutting conditions showed a suitable surface finish, especially V-MQL and SS-MQL. Under the cutting conditions used in this study, the ACO emulsion proved effective for machining ASTM A182 F55 steel, standing out as a promising alternative to conventional cutting fluids.