The Benefits of Using ADI

The remarkable increase in ADI production is reflected in 1995 - 2001 growth projections of more than 300%. With good reason: This is a material that offers improved product performance while reducing costs. In many applications ADI surpasses steel forgings, weldments, carburized steel and aluminium components. The following benefits point to ADI as the material of choice for many applications:

Reduced Manufacturing Costs

Although ADI costs less per kilogram than steel or aluminium, the real manufacturing economies only begin here. Through each step of the manufacturing process, an ADI-designed component can be produced for 20% less than forged steel and up to half the cost of aluminium. Some of the reasons for these cost reductions are:

  • Excellent castability. Easily cast into complex shapes, ductile iron has a high yield rate, i.e. the ratio of metal poured vs. metal shipped.

  • Lower machining cost. Nearer "net shape" casting requires less material and less metal removal. Additionally, when machined prior to austempering, ductile iron exhibits better machinability than free-machining steel. When machined, both ductile iron and ADI produce dense discontinuous chips that are easily handled, further reducing the net cost per pound.

  • Lower heat treating cost. When subjected to a specially designed austemper heat treatment, ductile iron can exhibit remarkable properties. Austempering heat treatment generally cost less than carburizing or induction hardening, and produces a higher degree of uniformity and predictable growth.

  • Less energy intensive than steel. Typically an ADI component consumes 50% less energy than a steel casting, and nearly 80% less energy than a steel forging.

  • Domestically produced. Not only are the shipping costs and time reduced, but reliability of production scheduling and delivery dates are improved. With ADI, economical local sourcing is the norm.

  • Best buy. When comparing relative cost per unit of yeild strength, in most instances ADI is the best buy (Fig. 1).

  • 100% recyclable.

  

Improved Product Performance

  • 10% less dense than steel. The relative weight per unit of strength of ADI compared to other materials (Fig. 2) allows economies of design without loss of performance. Thus, for a given shape, an ADI component will be 10% lighter. Further, ADI is as strong or stronger than microalloyed forged steel with comparable ductility and fracture toughness, and has better low temperature impact strength.

  • ADI strength is comparable to that of a variety of steels. The technology exists to replace nearly 80% of all cast and forged steels with some grade of ductile iron or with ADI, the new benchmark material (Fig. 3).

  • Superior wear/abrasion resistance. ADI's abrasion resistance exceeds that of conventionally processed steels and irons at a lower "bulk" hardness level. Unlike carburized steel, which loses wear resistance as the carburized case is worn down, the wear resistance of ADI improves in service (Fig. 4).

  • Excellent fatigue strength. ADI's dynamic properties exceed those of forged, cast and microalloyed steels. Unlike aluminium, ADI's endurance limit remains nearly constant after tens of millions of cycles (Fig. 5).

  • Lighter than aluminium? ADI is three times stronger than the best cast or forged aluminium and weighs only 2.6 times as much. Because it's twice as stiff, a properly designed ADI part can replace an aluminium part as a weight saving (Fig. 6).

  • Improved noise damping. 10% graphite in the ADI matrix substantially improves noise damping, for quieter running gears and components.
(Fig. 1)   (Fig. 2)   (Fig. 3)
   
Relative cost per unit yeild strength.   Relative weight per unit yeild strength   Comparative strength of steel vs ductile iron
         
(Fig. 4)   (Fig. 5)   (Fig. 6)
   
Pin Abrasion Test   Rotating Bending Fatigue   ADI vs Aluminium
         
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