Ductile iron is the name given to solid metal objects resulting from pouring molten ductile iron into cavities in a mould. Once cast, the ductile iron cools and solidifies, taking the shape of the cavity (or mould) it occupies.

What is Ductile Iron?

Invented in 1943, ductile iron is a modern manifestation of cast iron. Cast iron and ductile iron have contrasting physical properties resulting from differences in their microstructures. Graphite and carbon present in cast iron exist as flakes; cast iron exhibits positive compressive load capabilities. However, tensile strength above the inherent tensile strength can cause cracks to form and propagate rapidly through stress points within the flaky graphite microstructure. As a result, cast iron has almost no elongation. It is a brittle material and therefore its use in tensile and shock loading applications is limited.

Graphite within ductile cast iron occurs as spheroids, hence it is sometimes referred to as spheroidal graphite. Similarly, the term spheroidal derives from the fact that the carbon contained in ductile iron is held in a spherical shape. This unique microstructure allows ductile iron to withstand bending and shocks much better than conventional cast iron.

While ductile iron can be produced from steel or ferrous scrap, pig iron is the primary source for most modern ductile iron foundries. Pig iron refers to the primary iron production of a blast furnace containing over ninety per cent iron.

Pig iron is used as the primary source of pure iron in the production of ductile iron. Pig iron offers a number of unique advantages; it contains low residual or deleterious elements, has a consistent chemistry, supports optimum slag conditions and improves process control by providing consistent charge characteristics.

Demand for pig iron has increased in recent years as ductile iron foundries utilise its advantages over alternative iron sources, such as melting ferrous scrap or steel scrap and adding carbon.

What are the Advantages of Ductile Iron Casting?

Ductile iron has several advantages for manufacturers:

• Ductile iron can be easily cast and machined.
• It has an excellent strength to weight ratio.
• Ductile iron can be produced at a much lower cost than steel.
• It has superior castability and machinability.
• Ductile cast iron offers the designer an outstanding combination of durability, low cost production and reliability.

Where is Ductile Iron Used?

Ductile iron has greater strength and ductility than grey iron. These properties enable it to be used effectively in a wide range of industrial applications, including pipe, automotive components, wheels, gearboxes, pump housings, machine frames for the wind power industry and much more.

Since ductile cast iron does not fracture like grey iron, it can also be safely used in impact and shock protection applications such as posts, battlements and manhole covers.

• Material No : GGG50 – DDK50 – ASTM 70-50-05
• Tensile Strength : 500 N/mm²
• Yield Strength: 320 N/mm²
• Hardness: 170-220 (HB)
• Specific Gravity: 7.2 gr/cm³