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Darcast
has four state-of-the-art medium
frequency electric melting furnaces
capable of producing over 100,000
tonnes of base iron per annum. The
Company converts the base iron produced
in the electric melting furnaces
into spheroidal graphite iron using
the tundish method. Darcast utilises
the shell-moulded process to manufacture
its moulds. Given below are details
of the historical roots of the shell-moulded
process, the reasons why Darcast
selected this technology as
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the most appropriate
for crankshaft manufacture and the
advantages the shell-moulded process
offers to customers. Overall, the
shell-moulded process provides customers
with the best quality crankshafts
and the lowest total cost solution.
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The
History and Advantages of the Shell
Mould Process |
A Brief History:
The
shell-mould process was
patented
in Hamburg
in 1944 by Dr Johannes Croning,
and was originally referred
to as the Croning process.
The shell-mould process offers the following advantages:
- Near-net shape casting
- Excellent casting surface finish and definition
- Improved dimensional tolerances
- Improved micro-structure of metal
- Enhanced machinability
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The
shell-mould process was chosen by
Darcast
as being the best process to
manufacture
cast crankshafts. Using the
shell-mould
process and Darcast's unique
operational
capabilities, it is possible to
produce
enhanced material specifications
compared with other processes
such
as greensand manufacture.
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Typical
metal micro-structure
taken
from a crankshaft
produced
using the greensand process
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Typical
metal micro-structure
taken
from a Darcast crankshaft
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Darcast uses a variety of methods
for finishing crankshafts, ranging
from hand finishing for complex
and low volume items through to
the use of automated finishing presses
for high volume orders.
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