Tribological behaviour when face milling AISI 4140 steel with minimum quantity fluid application

Purpose - The purpose of this paper is to evaluate the performance of cutting fluid applied by minimum quantity technique when milling AISI 4140 steel with TiAlN coated cemented carbide inserts.Design methodology approach - The vegetable oil based cutting fluid evaluated was applied through a nozzle at the centre of the tool holder under vaporized conditions with a flow rate between 0 (dry cutting) and 200 ml h, at 50 ml h increments. Tool wear (based on maximum flank wear, VBmax), surface roughness parameters (Ra and Rt) and burr formation (length of burr, h) were recorded and evaluated. Scanning electron microscope images and energy dispersive X-ray analysis of the worn tools show adhesion as the dominant wear mechanism.Findings - Encouraging tool performance was recorded when milling AISI 4140 steel due to improved lubrication and cooling at the cutting interfaces. Increase in cutting fluid flow rate improves tool life with gradual reduction of the surface roughness parameters and negligible influence on the burr length generated.Practical implications - Results can be immediately applied on the shop floor.Originality value - The results show the improvement in tool wear after increase of the flow rate of the cutting fluid, applied by minimum quantity technique.