Performance of DLC coated tool during machining of MDN431 alloyed steel

Abstract

Highly alloyed steel are widely used in manufacturing of turbine materials because of its high resistance to corrosion and oxidation. MDN 431 is one of such material manufactured by Midhani. It’s having high hardness and strength which makes it hard-to-machine steel. DLC coating provide solution to this problem. DLC coating are developed using state of art PVD technique on the HSS tool. Turning process carried out on MDN431 steel using coated and uncoated HSS tool insert in both wet and dry condition. During the present investigation, speed, feed, and depth of cut varied according to full factorial design with level 3, consequently cutting forces, surface roughness (Ra) and tool wear were measured. The obtained results are optimized using factorial method for cutting forces and surface roughness. Using FFD method second order regression analysis carried out for each input variable and same compared with experimental values and found the developed model is with minimal error which supported by proof trials. Speed and depth of cut are inversely dependent on the cutting force and surface roughness whereas feed is opposite to it. Effect of DLC coating during machining of MDN431 is studied using optical profilometry in comparison with uncoated tool.