ADI (Austempered Ductile Iron)

ADI (Ausferritic Ductile Iron) represents a further stage in the development of the long-established standard material SG cast iron. Also known in the U.S. as Austempered Ductile Iron, ausferritic cast iron is formally defined in the German Industrial (DIN) Standard DIN EN 1564, and is produced by subjecting a particular alloy of nodular (SG) cast iron to an additional heat treatment process.

With its exceptional (for cast iron) mechanical properties, ADI offers a serious alternative to steel castings or forged parts (comparable or better strength and resistance to wear-and-tear, while being less expensive), as well as to aluminium (offering weight, volume, and cost benefits over comparable aluminium parts for high-loaded applications).

ADI is characterized by high strength under both static and dynamic loading (up to 1400 N/mm2) while simultaneously exhibiting favourable strain behaviour (up to 10%) and a high degree of toughness. The resistance to fatigue is comparable to that of steel; the vibratory damping behaviour, however, and thus the noise, is up to 40% better.

Given the lower density of cast iron, weight reductions of up to 10%, compared to steel, are typical, and given ADI’s better casting properties, further reductions in weight are possible with part designs tailored to the specific application. Additionally, machining is easier than for equally hard steel components.

Replacing aluminium components with ADI also offers advantages in terms of both volume and weight reduction; however, possibly more compelling is the cost reduction of up to 20%.

In addition to wearing parts such as gears, plow tips, chain links, cutting blades, guide rails, or excavator bucket teeth, ADI is also frequently used for highly loaded parts, such as those found in chassis or drivetrains (ring gears, axles/axle brackets, brake carriers, camshafts for heavy-duty motors, rollers, wheels, etc.).