Analysis of corrosion resistance when turning martensitic stainless steel X20Cr13 under chilled air-cooling

Abstract

Amongst different methods of cooling in machining, application of air is con-sidered to be the cleanest and most environmentally friendly one. The aim of this paper was to explore the possibility of chilled air-cooling considering the corrosion resistance when turning martensitic stainless steel X20Cr13. Thus, a comparison between an alternative cooling technique where compressed air is refrigerated and jetted to the cutting zone by means of Ranque-Hilsch coun-ter-flow vortex tube and the conventional flood cooling with oil-in-water emulsion was done. The corrosion resistance was determined by electro-chemical testing and the surface condition was analysed with both Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). From the results presented herein, it can be concluded that the specimen cooled with chilled air has better resistance to corrosion activity after a cer-tain longer time in relation to the specimen cooled with emulsion. In addition, the specimen cooled with chilled air has lower surface roughness, which has a positive effect on the corrosion resistance. Hence, in the scope of environmen-tally friendly machining the vortex tube based chilled air-cooling can be suc-cessfully applied when turning difficult-to-cut martensitic stainless steel.