Experiment and Optimization of Surface Roughness and Hardness of Inconel718 in Selective Laser Melting Using Taguchi Method

Experiment and Optimization of Surface Roughness and Hardness of Inconel718 in Selective Laser Melting Using Taguchi Method

Mohit Singh1, Hemendra Patle2, Puran Gour3

1Research Scholar Master of Technology (APS) Department of Mechanical Engineering, NIIST, Bhopal

2Assistant professor, Department of Mechanical Engineering, NIIST, Bhopal (M.P.)

3Principal, NIIST, Bhopal (M.P.)

Abstract

The primary objective of this research was to produce fully dense part of Inconel718 processed with selective laser melting with better mechanical and surface properties. Out of several factors, four substantial process parameters laser power, scan speed, layer thickness and orientation are selected with vii four levels of variations. Taguchi is one of the popular methods for design of experimental plan. Taguchi orthogonal array L16 was implemented for experimental runs. Here, experimental study is carried out for selective laser melting process with Inconel718 powder to explore the influence of process parameters on quality responses like surface roughness, porosity and hardness of built part. Scanning electron microscopy (SEM) and optical microscopy (OM) used for microstructural characterization of as fabricated SLM specimens. The ANOVA (Analysis of Variance) is well-known statistical tool, based on variation between the set of observations to determine the statistical significance of effects of factors on output responses. The study on effects of volumetric energy density on evolution of microstructure and defect formation was extended in second part. Nearly fully dense part with relative density at the level of 98.6% was obtained with applied energy density 101.5 J/mm3. Average surface roughness was obtained between 6.1 to 10.7µm average hardness 207 HV. Post process aging heat treatment upgraded the average hardness to 350 HV.

Keywords: ANOVA, Inconel718, Microstructure, Selective Laser Melting, Taguchi, Porosity, Hardness