An investigation on surface finish and flank wear in hard machining of solution treated and aged 18 % Ni maraging steel

Abstract

The hardened 18 % nickel maraging steels find potential application as an engine component for heavy vehicles and as armour metal in defence. The task lies in obtaining a good surface finish and minimal tool wear in hard machining of this high-strength material in a solution annealed and aged condition. The present work reports the optimal machining condition to obtain a good surface finish and lesser width of flank wear land during hard turning of maraging steel. The cutting speed, feed rate, and depth of cut are identified as the dominant parameters influencing the process responses. The working ranges of these machining parameters are set through the design of experiments, and an L27 orthogonal array is used for conducting the machining trials in a CNC lathe using cubic boron nitride (CBN) cutting inserts. The surface roughness is measured using a surface profilometer, while the width of flank wear land is found out using a video measuring system. The grey-based response surface methodology is used for analysis. A lower value of surface roughness (0.434 µm Ra) and lesser flank wear (0.0234 VBmax, mm) is obtained at optimal machining condition (cutting speed 174.28 m/min, feed rate 0.01 mm/rev, and depth of cut 0.3549 mm). Atomic force microscopy (AFM) images and P-profile graphs of machined surface are also examined. Furthermore, the temperature distribution is also simulated for the optimal machining condition using the DEFORM 3D software.