Ductile iron is finding increasing application for a very wide range of components in which it can replace gray iron because of its superior properties. Examples of automotive applications are crankshafts, exhaust manifolds, piston rings, and cylinder liners. The use of ductile iron in these applications provides increased strength and permits weight savings. Gray iron spun pipes have been largely superseded by ductile iron pipes having a high degree of ductility and thinner walls, and many fittings are also made of this material. In agricultural and earth-moving applications, bracket, couplings, rollers, hydraulic valves, sprocket wheels, and track components of improved strength and toughness are made of ductile iron. General engineering applications include hydraulic cylinders, mandrels, machine frames, switch gear, rolling mill rolls, tunnel segments, low-cost rolls, bar stock, rubber molds, street furniture such as covers and frames, and railway rail-clip supports. For these applications, ductile iron has provided increased performance or weight savings.

Ductile iron can be used to replace many more expensive components previously made in wrought or cast steels or other metals because of its higher strength-to-weight ratio, lower damping capacity, better machinability, and better castability. Examples include brake caliper and cylinders, steering gear and other safety-critical components, turbochargers, connecting rods, gear boxes and gears, valve bodies, pump components, bulldozer parts, nuclear fuel containers and transporters, bridge rollers and railing supports, coal and mineral crushing components, crane wheels, oil well equipment, mining roof supports, overhead switchgear, shaft and spindles, railway axle boxes and fittings for rolling stock, and low-pressure turbine casings.

Advantages of Ductile Iron Casting
Ductile Iron Casting provides Higher Tensile Strength, Less Deflection Under Load Conditions, No Straightning Required in Most Instances, No Problems With Hot Tears and Cracks, Good Machinability, Easier Feeding of Difficult Designs...

Typical Applications for Ductile Iron Casting
Ductile Iron Casting is particularly well suited for Valves, Pump - Gears and Rollers, Spring Hangers, Suspension Parts, Wheel Hubs, Bearing Caps, Hardware, Universal Joints, Threadless Connectors and Flanges, Various Automotive and Agricultural Items.

Ductile iron gears have performed well in non-critical engineering and agricultural applications, but austempered ductile iron offers a combination of strength, fatigue properties, and wear resistance that makes it of great interest for heavy engineering and automotive gears - applications in which the use of austempered ductile iron is likely to increase. Many new engineering components are likely to be amenable to design with ductile iron.

Here is the list of some grades of international standard for ductile iron (SG Iron) with its physical properties and comparisons with other international standards:

With its wide range of mechanical properties, Gray Iron Casting is suitable for many engineering applications, especially where intricacy of design is required. Gray Iron Casting is commonly used when ductility is not a factor.

Advantages of Gray Iron Casting
Gray Iron Casting provides advantages in the areas of cost, excellent machining, dampening capacity (ability to absorb vibrations). Good wear characteristics (self lubricating) and compressive Strength.

Typical Applications for Gray Iron Casting
Ductile Iron Casting is particularly well suited for Valves, Pump - Gears and Rollers, Spring Hangers, Suspension Parts, Wheel Hubs, Bearing Caps, Hardware, Universal Joints, Threadless Connectors and Flanges, Various Automotive and Agricultural Items.

The changes in physical and mechanical properties that can be produced in gray iron by controlling the characteristics of its free graphite and matrix structures lead to versatility in its application. Gray iron can be effectively used in highly competitive, low cost applications where its founding properties are of paramount importance. Such applications include implement weights, elevator counterweights, guards and frames, enclosures for electrical equipment, and fire hydrants. A variety of iron grades can be used in these applications. Gray iron is also employed in more critical applications in which mechanical or physical property requirements determine iron selection, such as in pressure-sensitive castings, automotive castings, and process furnace parts. gray iron casting is also suited for general machinery, stock fittings, automotive parts, valve bodies, railroad accessories...

Here is the list of some grades of international standard for gray cast iron with its physical properties and comparisons with other international standards: