Boy, Mehmet2024-09-292024-09-2920220256-24990973-7677https://doi.org/10.1007/s12046-022-01959-3https://hdl.handle.net/20.500.14619/4156Hard machining of Bohler steel is becoming important over years. This study aims to improve the machining performance of coated ceramic cutting tool under the turning of powder metallurgical hardened (from 30 to 60 HRC) Bohler K490 steel. The turning experiments were performed in dry, MQL, and nano-MQL environments using coated ceramic inserts. The machining parameters were chosen to be constant in all conditions, with a cutting speed of 150 m/min and feed rate of 0.1 mm/min and a depth of cut of 0.2 mm. Average surface roughness of machined surfaces, the tool wear of coated ceramic inserts, total power consumption in machining and chip morphology were evaluated for all cutting environments to see the effect of MQL, nano-MQL and the positions of their nozzles. As a result, the best values of tool wear, surface quality and power consumption were obtained by using the nano-MQL conditions, especially the dual jet nano-MQL technique.eninfo:eu-repo/semantics/closedAccessBohler K490 steelhard machiningcoated ceramic insertsnano-MQLArticle10.1007/s12046-022-01959-32-s2.0-851411331223Q247WOS:000847348400001Q3