High pressure water jet assisted turning (HPWJAT) consists of projecting a high pressure water jet, up to several hundred bar, into the tool-workpiece interface. The water jet is directed between the chip and the tool affording greater protection of the cutting face and better chip breaking. Comparisons are made between assisted turning using several jet pressures and conventional turning with different cutting speeds on the duplex stainless steel, X2CrNiMo22-5. The results show good chip fragmentation and an improvement of tool life with high pressure water jet assistance (HPWJAT). The evolution of the roughness is also investigated. It is shown that it is possible to improve the productivity by using HPWJAT.This study was undertaken by the Arts et Métiers ParisTech CER Angers in collaboration with two industrial partners: CETIM and Westafalia