Düker GmbH

Hot mould centrifugal casting for drainage pipes

For the manufacture of drainage pipes, Düker uses the hot mould centrifugal casting process. The liquid cast iron is poured into a hot, pipe-shaped mould that rotates around its longitudinal axis. Due to the rotation, the cast iron spreads very evenly on the inside walls of the mould and thus, after cooling, gives a pipe with extremely smooth inside surfaces. The smooth surfaces are excellently suited for the application of high-quality linings.
In other production processes of other manufacturers with water-cooled moulds, the pipe is built up little by little in a manner of speaking and therefore becomes considerably rougher, especially inside.
Fittings are cast in so-called lost moulds made of mould and core sand (green mould process).


Cast iron with flake (lamellar) graphite for drainage pipes and fittings

Grey cast iron with flake graphite
Grey cast iron with flake graphite

The material used for the manufacture of cast iron drainage pipes and fittings is cast iron with flake graphite (lamellar graphite), grey cast iron GG as per EN 1561 – type at least EN-GJL-150 (formerly GG 15 as per DIN 1691). An alloy of iron and carbon with a high content in graphite, which is included in the base material in lamellae form and finely spread. This material structure, which is typical for Düker, gives the material a high rigidity, wear, temperature and fire resistance, excellent corrosion resistance (as compared to steel) and a very high damping capacity. Cast iron drainage pipes by Düker therefore distinguish themselves by sturdiness, durability, fire resistance and noise-reduced operation – even without special insulation and sound damping measures.


The material characteristics

Cast iron with flake graphite is defined through a number of parameters such as elasticity module, tensile strength and crushing strength. Read more …


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