Ductile Iron Pipe Moulds

Ductile Iron Pipe has been recognised as the industry standard for modern water and wastewater systems since its introduction in 1955.

API Engineering supply Ductile Iron Pipe Moulds

To produce Ductile Iron Pipe, steel moulds are rotated at high speed before molten ductile iron is poured in. The centrifugal action of the spinning mould, forces the material to line the inside evenly. Once the ductile iron has cooled sufficiently the pipe can then be removed from the mould for further processing.

API Engineering supply the moulds used in this process, which must be able to withstand the high temperatures, forces and repeated heat-cycles of the process. These moulds are in use every day by the world’s leading producers of Ductile Iron Pipe.


Pipe moulds are manufactured from a hot work tool steel such as DIN 21CrMo10. A typical chemical composition would be:


0.16 - 0.23


0.20 – 0.40


0.20 – 0.40

P max


S max



2.20 – 2.60


0.30 – 0.50

Cu Max


Extra control for Pb, As, Sn, Sb and Bi may be implemented if required.

Mechanical Properties are typically:


> 780


> 650


> 16


> 60


> 78


> 240

Hardness variations shall not exceed 40 HBW throughout length of the mould.

Inspection of the taper

The internal diameter of a Pipe Mould has a shallow taper along its length to allow for easy removal of the product after casting. This taper is vital to ensure fast continuous production and under no circumstances can there be a reversal in the taper direction.

API Engineering use a variety of inspection techniques to ensure that this is the case, including dimensional inspection by laser.

Quality Assurance

API Engineering perform the following inspections on all Pipe Moulds:


All Pipe Moulds are packaged suitably for sea freight using preservative oil, waterproof wrapping and wooden or steel crates. Depending on mould diameters, multiple items can be packaged within one crate.