A brief overview of the
ductile iron pipe
manufacturing process.
Click here to see the
properties of ductile iron.

After treatment in the Fischer converter, iron is transferred to holding ladles behind each of the casting machines. Pipes 5.5 m long are centrifugally cast in machines containing water cooled steel moulds.
The internal profiles of the pipe sockets are formed to shape using sand cores. The wall thickness of the pipe is regulated by controlling the iron pouring rate, machine traverse and mould spinning speed.

Raw materials used in the production of ductile iron
are scrap steel, ductile iron returns, ferrosilicon,
coke and limestone.

The raw materials are charged into a hot blast cupola in strictly controlled quantities and the resultant molten metal is discharged in a continuous stream at a temperature of 1550°C into a hot metal receiver.
The base iron is poured into a Fischer Converter where it is desulphurised and the graphite nodularised by the addition of metallic magnesium.

After heat treatment all pipes are tested for ductility with a ball impression tester. A hardened steel ball is punched into the inner wall of the spigot. A non-ductile pipe would split under the high pressure, and would be rejected.
All pipes are hydrostatically pressure tested to 5 MPa for pipes up to DN 300, 4 MPa for pipes up to DN 600 and 3.2 MPa for DN 750.

The majority of pipes are cement mortar lined by a centrifugal spinning process, externally coated with a bituminous paint and stencilled with relevant information such as pipe size, class, Standards’ mark and company name.
Pipes are transferred to stockyard by fork lift truck and a 48 hour curing period is allowed for cement lined pipe prior to despatch.