Ductile And SG Iron Castings

The structure of ductile iron, which is graphite nodules in a relatively pure iron matrix, has several useful properties. Firstly, the metal expands slightly on solidifying as the graphite precipitates, resulting in sharp, well defined castings. The graphite content also offers good corrosion resistance, particularly when compared to mild steel.

Ductile Iron Castings

Pattern Equipment for Spherical Backed Bearings to be made in Ductile Iron

Cast Iron Castings

Ductile Cast Iron

Typical Applications for Ductile & SG Iron Castings

  • Engineering Castings
  • Heavy Engineering Plant & Equipment
  • Original Equipment Manufacturers
  • Petrochemical & Oil Production Sector
  • Aerospace Applications
  • Shipping Construction
  • Transportation Infrastructure & Railway Stock
  • Mining, Quarrying & Minerals
  • Energy Sector & Power Production
  • Hydro Applications
  • Pump & Valve Manufacturers
  • Rolling Mills & Steel Production
  • Special Engineering Cast Iron Castings
  • Architectural Castings
  • Decorative Castings


Due to the shape of the graphite, ductile iron is not brittle like normal cast iron and can therefore be used where toughness and resistance to shock loading is required. The mechanical properties of ductile irons are more that of basic cast steels and ductile iron can often be used as a cheaper alternative, whilst still offering acceptable service performance. Graphite also acts as a lubricant, improving wear resistance.

Properties And Applications for Ductile Iron Castings

Ductile iron is characterized by having all of its graphite occur in microscopic spheroids. Although this graphite constitutes about 10% by volume of ductile iron, its compact spherical shape minimizes the effect on mechanical properties and results in a structure that is ductile rather than brittle, as is the case with normal flake graphite cast irons. This ductility has produced a cast iron which can perform in areas which previously had been limited to aluminium or cast and forged steel, often at lower cost. It also has superior corrosion resistance compared to a mild steel. One area of high usage is in pipes and flanges for water pumping where its low cost and good corrosion resistance gives advantages over steel pipe. Another area where ductile iron has been used extensively is in the automotive industry where it can provide high strength and low cost alternatives to aluminium.

These properties, coupled with the ease by which complex shapes can be produced at a relatively cheap cost compared to other production methods and materials has resulted in a wide range of end uses. The relatively low cost of ductile cast iron along with the ability to produce highly complex shapes has led to its use in decorative and architectural castings such as street furniture, lamp posts, seating, fountains, floor grates and railings.

It is also suitable for a wide range of component weights from a few grams to hundreds of tonnes and in quantities from one off to thousands off. A wide range of replacement parts and finished goods are in demand to replace older Castings which may have perished or reach the end of their life cycle.

Due to its ability to produce complex shapes, it is also used for artistic work such as sculptures.

At Durham Foundry we have been producing ductile iron castings for over a 40 years. Our customer base covers the engineering, decorative, architectural and artistic sectors and we supply castings from one off up to small to medium batch production using Alpha Phenolic resin bonded sands. Our workforce of highly skilled moulders can work from complex loose pattern equipment, particularly where low volumes are required, whilst our moulding line is suited for batch production. Our long trading history, coupled with an investment programme that has enabled us to keep up with modern production methods and environmental legislation has meant that we are approved suppliers to companies such as Corus, Sheffield Forgemasters and Firth Rixson.

Please browse our website for more information about Engineering Ductile Iron Castings from Durham Foundry and our ability to manufacture Engineering Ductile Iron Castings then contact us on 0114 249 4977 or e-mail us on castings@durhamfoundry.com.

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