Mathematical modelling of superalloy remelting operations

In order to produce Ni base superalloys for a critical use, it is necessary to control the whole processing route, and especially to master the solidification process. Thus, an essential step is the consumable electrode remelting operation (electroslag remelting or vacuum arc remelting) which produces the solidified ingot. Both processes are characterised by a fair control of the melting rate and a high cooling rate, even for large diameter ingots. Studies based on mathematical modelling and numerical simulation enable one to link the local solidification conditions to the operating parameters. The present paper discusses the use and validation of numerical models for secondary melting. It is shown that modelling is a valuable tool for superalloy producers to prevent features such as white spot formation and to predict freckling tendency.