Düker GmbH

The material cast iron for sewage pipes

Sewage pipe production at Düker

The material cast iron with flake graphite (lamellar graphite) of Düker cast iron sewage pipes and fittings corresponds to the requirements of EN 877, with the following characteristics:



approx. 7.2 kg/dm³ (71,5 KN/m³)

Minimum tensile strength:

150 MPa for fittings,
200 MPa for pipes

Compressive strength

approx. 3 to 4 times the value of the minimum tensile strength

Shearing strength:

1.1 to 1.6 times the value of the minimum tensile strength

Crushing strength:

350 MPa (for DN < 250)
332 MPa (for DN = 250 or larger)

Poisson‘s number:


Length expansion coefficient:

0.0105 mm/mK (between 0° and 100°C)

Thermal conduction:

50 - 60 W/mK (at 20°C)

Modulus of elasticity:

between 80,000 and 120,000 N/mm²



Cast iron pipes and recycling

After their useful life, Düker cast iron drainage pipes and fittings are recycled at practically 100%, and they have been produced from 95% used cast iron for decades. Cast iron has been a recycling product in the modern sense of the term for centuries.
Most plastic pipes, however, are not recycled, but burnt or disposed of at waste sites. For the manufacture of HDPE drainage pipes, manufacturers use exclusively new material, as the existing recycling plastic material is not up to the requirements.


+ + + Düker GmbH + + +