It is recommended that cutting fluids with high flow rate are used when stainless steels are machined. However, conventional mineral oil-based cutting fluids have a negative impact on the environment, workers' health and production costs. Alternative cooling technique with cooled compressed air using the Ranque-Hilsch's counter-flow vortex tube in machining of martensitic stainless steel X20Cr13 by turning is the subject of this research. The aim was to determine the effect of such cooling on the corrosion resistance of the machined surface and its technological and economic viability compared to conventional emulsion cooling for the purpose of achieving ecologically acceptable machining. The air as a cooling medium is completely natural so this cooling technique is the cleanest and most environmentally acceptable one. Since corrosion can also occur in dry machining, corrosion resistance was determined by electrochemical and gravimetric measurements. The chemical composition and appearance of the surface before and after the corrosion resistance test was determined by scanning electron microscopy in combination with energy dispersive X-ray spectroscopy. Particularly important is the discovery that the surface of the test material machined by the turning operation with cooling by means of the vortex tube is more resistant to corrosion than that obtained by the turning operation with cooling by means of the emulsion. Also, it has been confirmed that the machined surface minimum roughness ensures maximum corrosion resistance. The role analysis of the machined surface minimum roughness in the corrosion of stainless steel is particularly interesting as this parameter can be traced yet in the machining process, and this is adopted in this research. By the analysis of variance of the experimental results obtained by the machinability testing according to the rotatable central composite design of the experiments, it was found that various cooling techniques (emulsion or vortex tube) did not significantly influence the machined surface roughness of test material, and hence the corrosion resistance. By the original calculation of the unit production cost, it has been proved that the cooling with the vortex tube offers an economical solution on the route to sustainable machining. It is concluded that the cooling with cooled compressed air using the vortex tube positively affects all three segments of sustainable development – ecologic, sociologic and economic, so for the turning of martensitic stainless steel X20Cr13, instead of conventional cooling by emulsion, the cooling with the vortex tube is recommended.