Cast Iron Castings Applications
The structure of cast iron, which is graphite flakes 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. Graphite acts as a lubricant, improving wear resistance.
Typical Applications For Cast 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
Mechanical Properties For Cast Iron Castings
The exceptionally high speed of sound in graphite gives cast iron a very high thermal conductivity. Since ferrite is so different in this respect (having heavier atoms, bonded much less tightly) phonons tend to scatter at the interface between the two materials. In practical terms, this means that cast iron tends to “damp” mechanical vibrations (including sound), which can help machinery to run more smoothly. All of these properties ease the machining of grey cast iron. The sharp edges of the graphite flakes also tend to concentrate stress, allowing cracks to form much more easily, so that material can be removed much more efficiently.
Easier initiation of cracks can be a drawback once an item is finished, however: grey cast iron has less tensile strength and shock resistance than steel. It is also difficult to weld. However, compressive strength can be almost as high as for some mild steels.
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 good thermal properties of cast iron have led to uses in forges and rolling mills and in the production of brake disks and drums, particularly where castings are subject to repeated heating and cooling cycles. Its damping properties have led to uses in motor housings, gearboxes, engine blocks and machinery components. The relatively low cost of 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 cast iron castings for over a hundred 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.