Research and development in gravity casting has taken an important
step in making metal products a part of our day to day lives.
The products used in homes, aircrafts, artifacts,
automobiles have become more durable and less expensive.
Cast alloy parts are formed by melting the alloy and then
pouring it in a mold under heavy pressure or vacuum.
Gravity casting is also known as vacuum casting. It is
a technique in which large diameter filaments are used
with adequate separation. This ensures that no clusters
are formed and also good metal wetting of the fiber is
guaranteed. This technique was first used in 1970.
The gravity casting method has advantages like cost
effective, good quality, and process control over
other casting techniques.
Gravity casting is done in ceramic molds, sand, permanent
casting and also in investment or lost wax casting.
The gravity casting process was started with common
steel after successful implementation it was further tried
on heat resistance super alloys. With recent development
and with more refined methods today even titanium alloys
are being cast using the gravity casting method and using
ceramic crucibles. The use of desired mold designs and
also specially made unique designs enable a reduction
in the metal cast to yield the given part. This also
helps in reducing the amount of energy that is used
in making such casting articles.
With new developments, today even computerized
control of the vacuum pressure and rate is possible.
This enables the user to control the filling rate. This
makes casting of high quality metals like and viscous
metals like metal matrix and composites of aluminum
casting possible. This gravity casting method is
used to produce casting worth of more than $200
million. The industry is expected to grow rapidly in
the coming years due to the increase in production
of automotive exhaust manifolds in stainless steel.
The first ever commercial use of this computerized
technology, was made by Howmet Industries of
Whitehall, Michigan. They used this technology to
precisely cast and design turbine blades used in aircrafts.
This technology is also being used by Ford Motors
to develop and improve the casting process
of light truck and automobile engine blocks.
Today, metal parts fabricated using gravity casting
method is being used in 90 per – cent of all durable
goods. Goods like stoves, washing machine, automobiles,
refrigerators, lawn mowers, cars and even boats
. Many other articles like badminton rackets, tennis rackets,
and even football studs are made by using light weight
metals which are gravity casting method. This gravity
casting method has been used to develop metal alloy parts,
which are used for the auto and airline industries,
which is said to make vehicles lighter though much
stronger and extremely efficient.
Alloys like ferric cast metals, casting grade iron and
steel are typical metals that are used for gravity
casting. Also die cast grade zinc can be cast using
gravity casting method. Also other raw materials like
sand, spin or plaster are used. Aluminum is also used,
but it is very difficult to gravity cast aluminum a lot
of care needs to be taken and proper pressure
should be applied to obtain the desired shape and effect.