Turning of hardened AISI H13 steel with recently developed S3P-AlTiSiN coated carbide tool using MWCNT mixed nanofluid under minimum quantity lubrication

Abstract

This article aims to analyze the tool vibration, surface roughness, and chip morphology in hard turning of hot work AISI H13 steel under multi-walled carbon nanotubes mixed nanofluid with minimum quantity lubrication. Recently developed new-generation nanocomposite AlTiSiN coating deposited on carbide insert via scalable pulsed power plasma (S3P) strategy is used as cutting tool material. The experiments associated with 30 number of trials are performed by considering various machining parameters that includes cutting speed, nose radius, depth of cut, and feed. In perspective of predictive modeling and multi-response optimization, response surface methodology has been engaged as a means to minimize the tool vibration and surface roughness. At last, with the measured tool life and based on the Gilbert’s machining economic model, a distinctive cost analysis has been implemented to demonstrate the cost-effectiveness of coated carbide tool in hard turning. Statistical analysis confirms that nose radius with 36.65% has the highest contribution for surface roughness and cutting speed with 53.88% has the highest contribution for tool vibration. Increased flank wear and tool vibration are responsible for degradation of machined surface finish. Machining under nanofluid-MQL, chip morphology revealed the production of segmented type serrated saw-toothed chips. At higher cutting speed resulted: (a) obvious shape of saw tooth chip, (b) increase of distance among saw tooth, (c) reduction in chip segmentation frequency, (d) decrease of chip thickness. At optimum combination of process variables (v = 55 m/min, d = 0.2 mm, r = 1.2 mm, f = 0.07 mm/rev), the life of AlTiSiN coated carbide tool is found to be 42 min under nanofluid-MQL and estimated the total machining cost expenditure per finished part of Rs. 153.52. New-generation AlTiSiN coated carbide tools can be competently and productively utilized for machining of hot work tool steel under ecologically cognizant minimum quantity cooling-lubrication, is the most accepted in industrial applications.