The base price of ADI material is lower per kilo than steel or aluminium but this accounts for only a fraction of the potential savings. Designing with ADI can save cost at each stage of manufacture; parts can then be produced for less than a steel forging or for half of the cost in aluminium. Several factors favour ADI in value engineering:
Excellent castability: Readily cast into complex shapes, Ductile Iron has a very high yield rate i.e. the proportion of metal poured versus metal shipped.
Lower machining cost: Well suited to near net shape casting, ADI requires less starting material and less metal removal. Prior to Austempering, Ductile Iron exhibits better machinability than free-machining steels. Both Ductile Iron and ADI produce dense, discontinuous chips that are easily handled, further reducing cost per kilo.
Heat treatment savings: Austempering generally costs less than Carburising or Induction Hardening, and produces a higher degree of uniformity and predictable dimensional changes.
Low energy content: Producing a typical ADI casting consumes 50% less energy than a steel casting, and 80% less energy than a steel forging.
Best value: When comparing relative cost per unit of yield strength, ADI is generally the best buy.