ThyssenKrupp VDM GmbH has completed a multi-phase investment programme at its Unna melting plant. With its new vacuum induction furnace, which began operation in September 2003, and two previously built remelting facilities, ThyssenKrupp VDM now has all the ingredients in place at Unna to produce nickel and cobalt-base superalloys. The Werdohl-based company already produces heat- and corrosion-resistant nickel-base alloys, but the superalloys produced in the new facilities meet even higher demands: they are used for example in rotating parts for aircraft turbines. Other applications include highly stressed parts in the space, electronics, electrical, energy and chemicals sectors. Almost all metals for aircraft turbines are produced today by remelting. Superalloys made by vacuum melting account for 30% of the entire market for nickel and cobalt alloys. Typical uses for superalloys are turbine blades in aeroengines or gas turbines: in an aircraft these components reach temperatures of 700 degrees, rotate around 5000 times a minute (for example in the Airbus A 340) and are subjected to high stresses due to centrifugal force. In gas turbines, the speeds are lower and temperatures not quite so high, but an additional stress factor is corrosion, caused by combustion residues such as sulphates and chlorides.
