Influence of heat treatment on the tool life while machining SLM Inconel 718 with reference to C&W Inconel 718

Abstract

In this study tool life experiments were performed on Inconel 718 (IN718) alloy. The Inconel 718 samples were produced by conventional Cast and Wrought (C&W) and by Laser Powder Bed Fusion (L-PBF) techniques like Selective Laser Melting (SLM). The as-built SLM samples which were subjected to only Hot Isostatic Pressing (HIP) are labeled as SLM HIP and both Hot Isostatic Pressing and Aeronautic Heat Treatment are labeled as SLM HIP-AHT. The tool life machining tests were performed using PVD coated carbide insert under emulsion conditions. The surface integrity parameters such as surface roughness, residual stresses, and microhardness were evaluated. The wear mechanisms on the rake and flank faces of the PVD insert were characterized. It's deduced that notch and flank wear near the depth of the cutting zone were the predominant failure mode affecting the tool life. The age-hardened microstructural features of C&W and HIP heat-treated SLM samples have a negative impact on the tool life. Whereas the microstructure obtained by the SLM HIP-AHT sample indeed played an important role by exhibiting 26 % more tool life than SLM HIP samples and 79 % more tool life than the C&W sample.