The application of magnetic moulding in casting of a ductile iron valve
Abstract
Impeding problems experienced in the valve manufacturing industry has resulted in
the cost of locally manufactured valves to be up to 60% more expensive than imported
products. The overall cost of manufactured products may be reduced by increasing
the efficiency of manufacturing methods.
A review and investigation of various manufacturing methods have led to the selection
of the magnetic moulding process for further investigation. It was determined
that due to the traditional mould materials used for the casting of cast irons, variation
and control of the microstructure, determined by cooling rate, is limited. If the thermal
conductivity of the mould material can be varied or controlled, substantial microstructural
variation becomes possible that can substantially improve the strength of the cast
product and lower the overall cost of local valve manufacturing.
The feasibility of the magnetic moulding process on the casting of a ductile iron valve
was tested by implementing this casting method. A casting was performed with an
additive manufactured PMMA pattern and due to inconclusive results, a wire-cut EPS
pattern with a square geometry was cast successfully with this method. The results of
both castings were analysed by means of microstructural inspection and the testing of
mechanical properties.
Ultimately, it was concluded that the magnetic moulding casting process is a feasible
manufacturing method with the potential to increase the affordability of locally manufactured
valves if a low-density pattern material, such as EPS, is used. Additionally,
it is a viable method that offers a vast amount of opportunities to vary the microstructural
properties of cast iron if it is to be further implemented in valve casting.
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- Engineering [1403]