Induction forging of axel shafts
When it enters passenger service in 2006 the Airbus A380 will be the world’s only twin-deck, four-aisle airliner. EFD Induction France is proud to play a key role in getting—and keeping—this new flagship of the Airbus family airborne.
Whichever way you look at it, the new Airbus A380 aircraft is an engineering marvel. A double-decker giant that can carry 555 passengers in non-stop comfort for 15,000km (8,000 nautical miles), the A380 checks in with a length of 73m (239ft 3in), a geometric wing span of 79.8m (261ft8in) and a maximum take-off weight of 560 tonnes (1,235,000lbs). Lifting all this off the ground are four double flex jet engines with a thrust range of 70,000lbs slst. Obviously, each and every engine component must be of the highest possible quality. But the main engine shaft has to be especially well made, as it must withstand high torques, high rotation speeds and unusually high temperatures. The responsibility for making the shafts lies with Aubert et Duval, a company recognized as one of the world’s leading specialists in the ‘refractory’ alloys used in the aero-space and other high-tech industries. Aubert et Duval will deliver forged preforms to the engine manufacturers, who in turn will machine them into the main engine axle shafts.
Forging these 250mm diameter bars of special alloyed steel calls for a rapid pre-heating to 1250°C, with a narrow tolerance of +/– 10°C. Which is why Aubert et Duval turned to EFD Induction to design and supply an induction solution that can pre-heat with such accuracy. The result is a complete induction system that includes handling equipment. Also included is control equipment capable of controlling all parameters. Each of the system’s three induction converters delivers 100 kW at 1,000 Hz, thus allowing fine adjustments of temperature.
Also featured is a feedback signal from the 8,000 ton press that lets the system supply a part ready to forge at exactly the right moment. This accuracy avoids overheating and excessive soaking time, both of which are detrimental to quality because they lead to increased grain size and oxidation. The induction system has been designed and built by Soldago, EFD Induction’s French subsidiary specializing in induction heating solutions for forging and melting.