A model-based VAR control method incorporating an accurate, low-order process model is capable of simultaneously controlling VAR melt rate and electrode gap to optimize VAR castings.
Vacuum arc remelting (VAR) is a process used throughout the specialty metals industry to control casting of segregation-sensitive and reactive metal alloy ingots. Of particular importance in the former group are nickel-base superalloys such as Alloy 718, commonly used for forged rotating parts in the hot stages of jet aircraft engines and increasingly in land-based turbines for power generation. Reactive metal alloys include titanium, zirconium and uranium alloys, such as Ti-6Al-4V, which is used for a variety of aerospace applications. VAR also is used to produce various grades of forgeable stainless steel ingots.