Work

How the wear of WC and PCBN inserts affects the surface integrity of Inconel 718 in dry, flood and cryogenic finish turning

Year: 2026

Type: article

Abstract: Aerospace components must adhere to extremely stringent reliability standards, necessitating the use of high-performance alloys such as Inconel 718. While valued for its superior mechanical properties across a wide temperature range, Inconel 718 is notoriously difficult to machine, often resulting in rapid tool wear and compromised surface integrity. Furthermore, Inconel 718 is usually machined using conventional flood lubrication, which poses sustainability challenges and high disposal costs. This study has the twofold objective of (i) evaluating the feasibility of dry and cryogenic finishing turning as eco-friendly alternatives to traditional flood lubrication, and (ii) assessing the performance of polycrystalline cubic boron nitride (PCBN) inserts and traditional coated tungsten carbide (WC) ones, each operated under its supplier-recommended conditions. Tool wear and surface roughness were continuously monitored throughout the experimental campaign, while surface integrity was evaluated at the end of the inserts’ life for each cutting condition investigated. Results indicate that the dominant wear mechanisms of WC inserts were abrasion and adhesion under all tested lubrication-cooling conditions, although cryogenic cooling slightly extended their life while simultaneously producing smoother surfaces and a thinner severely plastically deformed layer. Although PCBN inserts exhibited a shorter tool life under the adopted high-speed conditions, they showed comparable lifetimes under dry and flood conditions. Cryogenic cooling instead led to a low defective surface and a thin SPD layer comparable to the flood reference case without the need of high-flow lubricant adduction. While lubrication strategies and cutting speeds significantly influenced surface characteristics, all tested conditions met aerospace standards, confirming the industrial viability of sustainable machining strategies for Inconel 718.

Source: CIRP journal of manufacturing science and technology

DOI: 10.1016/j.cirpj.2026.11.001

Authors: Nicola Pozzato, Rachele Bertolini, Andrea Ghiotti, Stefania Bruschi

Institution: University of Padua

Language: English

Topic: Advanced machining processes and optimization

Subfield: Mechanical Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $2,950

Funder: Dipartimento di Matematica 'Tullio Levi-Civita' Università di Padova