4. Elaboration

A large number of superalloys, particularly Fe – Ni and Co bases, are produced in air under the same conditions as stainless steels. However, the initial melting process in a vacuum induction furnace is necessary for alloys used at high stress levels. In the case of ingot production, vacuum induction furnace (VIF) melting produces an electrode which is subsequently remelted under vacuum (RAV) or under slag (RSL). The use of a VIF furnace reduces the gas content (O, N), and enables better control of the content of the most reactive elements: Al, Ti, etc.