When the structure has a lighter potential than aluminum components

For decades, the use of aluminum, titanium and magnesium components has been regarded as a universal remedy for optimizing the weight of sophisticated structural components. ADI, a new cast iron grade, has been available as a design material for some years now, which, in the triad of costs, resilience and production reliability availability, repeatedly reduces this trend to absurdity.When selecting a suitable material, the designer is spoilt for choice: either high-strength, but brittle, or tough, but less rigid. An optimization of these opposing properties is not possible with conventional construction materials.

The group of ADI cast iron materials is opening up new possibilities in this area of conflict ADI stands for Austempered Ductile Iron and refers to heat-treated ductile cast iron which is twice as rigidas conventional ductile cast iron with spheroidal graphite at the same elongation at break  The tensile strength is comparable to that of many steel gradeswith exponentially superior shaping properties. Compared to spheroidal graphite iron, the fatigue strength is almost twice as high. As a typical cast-iron material, ADI has a  below that of steel. Due to its high graphite content it also offers the good  damping capacity typical for cast iron.

Typical applications include materials handling, agricultural, construction and mining, rail  technology, as well as applications for commercial and passenger vehicles, fittings, transmissions and pumps. Apart from wear parts such as plough tips, guide rails, chain links, cutting edges and excavator teeth, highly stressed components such as chassis components and drive components hollow wheels, axles axle bridges, brake carriers, camshafts for heavy-duty engines, rollers, wheels are frequent applications.However gears sometimes are replaced by ADI gears for another reason: noise reduction that can only be obtained in this way is a major reason.

The additional effect of the constantly renewed hardening of the surface layer under load also increases the service life of the component.The notch sensitivity ratio, which describes the ratio of fatigue strength of unnotched and notched workpieces, is between  for ADI for the examined notch geometries and between  for forged steel. ADI is therefore not very notch-sensitive whereby the significance of traditional notched bar impact tests for cast iron materials can be queried. In contrast to conventional nodular cast iron grades, the fatigue strength of non-notched ADI samples is not proportional to the tensile strength, instead it shows a maximum for those materials which contain a particularly high proportion of stabilized austenite because of temperature control during heat treatment. The tensile strength in ADI is not a measure of the fatigue strength - an assessment must be made using the so-called  or to determine the fracture toughness in the flat elongation state.