Weighed quantity
of aluminum ingots are charged in induction furnace
and furnace is put on to raise temperature to about
750 ± 30 ° C. At this temperature, weighed
quantity of silicon is added and heating is continued
for another 10 - 15 minutes and then the required weighed
quantity of zinc is added.
A weighed quantity of indium is added just before pouring
the alloy melt into the preheated ladle.
Meanwhile, the moulds are inspected and cleant of dirt,
etc.
The steel inserts are placed and checked for its positioning.
Moulds are then heated to remove the moisture in the
mould-wash and subsequently inserts are also heated
for better bonding between aluminum and inserts.
The alloy melt is then poured into the mould, slowly
and carefully, after removal of slag from the ladle.
Temperature is recorded before and after each pour and
precaution is taken that it does not fall below 7050C.
A total of six samples is taken in every heat i.e.,
two samples of cylindrical type for electrochemical
test and one of circular type for chemical analysis
at the start of the pouring and the same will be at
the end of pouring. Both types of samples will be cast
in separate moulds.
After pouring the melt, adequate cooling is done and
the casting is removed after solidification. The hot
casting is removed by crane, forklift or manually and
kept in the inspection zone. After cooling down of the
casting, anode is inspected visually for its surface
condition and is punched with heat number, anode number,
size and date of manufacturing.
Visually rejected anodes are sent back for re-melting
and accepted anodes are sent to the workshop for cutting
and finishing of risers, runners etc.
The finished anodes are then weighed and checked for
its dimensional tolerance and are then kept in the final
inspection zone.
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