Effect of the crucible composition on the Inconel 718 vacuum induction melting process efficiency

Nickel-based superalloys are widely employed to manufacture aero-engine turbines due to their high mechanical strength and resistance to corrosion and creep. Vacuum Induction Melting (VIM) is a suitable manufacturing technology because of the reactive nature of the alloying elements; however, the melting process is time-consuming and energy-demanding. This research focuses on increasing the overall efficiency of the process in two ways. Initially, studying the influence of metal-containing crucible composition and thermal properties on the melting. In a semi-industrial VIM facility, 2 kg of Inconel 718 alloy was melted employing Al2O3, ZrO2, MgO, and Al6Si4O13-based crucibles. The Al6Si4O13 and ZrO2-based crucibles reduced energy consumption by 28% and 23%, respectively, compared to the reference crucible of Al2O3. Subsequently, an optimized melting procedure is proposed to reduce the process cycle time and energy demand, saving 10%-20% for all crucibles compared to the standard melting procedure. In addition, the ZrO2 and Al6Si4O13 crucibles reduced total cycle time by 13% and 21%, respectively. During melting, intense dross formation was detected for all crucibles, dissipating faster for Al6Si4O13 and MgO crucibles. Therefore, the metal-crucible interface product was analyzed to understand these mechanisms better, and the four crucibles' chemical reactivity was examined.(c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).