Experimental Investigations into Turning of Hardened AISI 4340 Steel using Vegetable based Cutting Fluids under Minimum Quantity Lubrication

Machining is the key process in every manufacturing and production industry. Heat generated during machining cause several negative impacts on tool and overall machining environment. Minimum Quantity Lubrication (MQL) is the key process, which signifies the exact amount of cutting fluid during machining. Current industrial practices are moreover inclined towards environment friendly processes. In view of the same, we have chosen vegetable based cutting fluids namely; canola oil, coconut oil and soybean oil for investigation of surface roughness and tool life of the hardened AISI 4340 steel during turning operation at higher cutting speed range, keeping feed rate and depth of cut at constant level. This experimental investigation is the successful move towards evaluation of machining characteristics at aggressive cutting speed. Overall study shows that, canola oil gives better performance comparatively. At higher cutting speed, use of traditional oil with MQL shows longer tool life than vegetable based cutting fluids. Surface roughness is studied under the additional environment of dry cutting. Varying cutting speed did not show any significant impact on surface roughness, as feed rate was constant throughout the experiment. Tool wear is observed after every machining cut by virtue of average flank wear.