Annual report 2009 - Siempelkamp
Annual report 2009 - Siempelkamp
Annual report 2009 - Siempelkamp
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The melting process starts with the melting of pig iron and steel scrap in a certain<br />
proportion along with additives. Adding magnesium to the molten mass results in the<br />
carbon to solidify as spherulite. Embedded into the ferritic matrix, this composition has<br />
many good properties:<br />
high tensile strength<br />
stable yield stress<br />
good elongation after fracture<br />
good deformability<br />
optimal damping features<br />
good fatigue strength<br />
Compared to steel, the castings made of this material have minimal shrinkage as they<br />
cool. Therefore, the familiar defects in steel castings caused by material shrinkage during<br />
the cooling process can be largely avoided. This is a tremendous advantage especially for<br />
component parts that are highly stressed in selective areas! Since the castings are near the<br />
fi nish shape when leaving the mold and typically exhibit a ferritic matrix, casting with<br />
nodular graphite cast iron saves time during mechanical machining and imposes minimal<br />
wear to tools. Furthermore, casting with nodular graphite cast iron opens up considerable<br />
advantages in regard to effi ciency for our customers. Since no heat treatment is necessary,<br />
we cut down on one entire production step and save energy. For castings with a weight of<br />
up to 300 t (331 US tons) this means considerable savings!<br />
Due to the fact that we have special know-how in the composition (metallurgy) of the<br />
molten metal, we have a high demand for parts with piece weights of over 150 t (165 US<br />
tons). The area of castings with wall thicknesses above 200 mm (7.9 in) requires special<br />
knowledge because of the involved slow cooling process. Once the product has solidifi ed<br />
and has been removed from the mold, the quality chain continues in the fettling shop.<br />
Sand build-ups and fl ashes are removed and our inspectors perform non-destructive<br />
testing by means of ultrasound to fi nd out whether defects inside the material exist.<br />
Metallographic testing examines cuts under a microscope and assesses the product<br />
quality via the microstructure. If desired by the customer, the next step is the machining of<br />
the casting. This step is carried out for approx. 30% of our projects. Finally, the castings<br />
are shipped to their destinations.<br />
<strong>Siempelkamp</strong> Casting technology<br />
Foundry<br />
Pouring ladle during deslagging<br />
Diesel engine block in fettling shop<br />
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