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Sand Castings in China
Sand castings mean the metal castings
produced by sand molds. There are many types of sand castings in
China, such
as gray iron, ductile iron sand castings, carbon steel sand
castings and aluminum sand castings etc.
There are many types of sands that can be used for sand casting
process, including green sand, resin sand, pre-coated resin sand,
water glass dry sand etc. Accordingly, the sand casting processes
include floor molding,
automatic molding and
shell molding process.
In the total metal casting output in the whole world, 60% to 70% of
metal castings are sand castings. Their unit weight could from
dozens of gram to dozens of tons, and their dimensions could be from
dozens of millimeters to several meters. Moreover, according to the
castings produced by other casting processes, sand castings are the
cheapest and have very high production rate.
However, sand castings have many defects, such as sand holes, air
holes, shrinkage, cracks, uneven materials, deformation etc. These
defects are the main disadvantages for sand castings. However, as
for the sand castings made by shell molding process, their defects
are very few. So, more and more clients have required their
suppliers to use shell molding process.
For your reference, if your products need high dimensional tolerance
for rough castings, then you should use shell molding process,
although this process is more costly then others.
If your products are large, such as from 1 meter to 2 meter long,
from 100 kg to 2 tons, then you should use the resin sand casting
process.
If your products are larger than 2 tons, such as the dryer cylinder
for paper machinery, then you still need to use the green sand
casting process.
If you need very high production rate, such as the automotive parts,
then you should use the automatic molding line.
It is easy to find the metal foundries for producing sand castings
in China, however, the technical levels have large difference
between them. According to my years working experience in
Dandong Foundry, I think it is
really not an easy word to produce qualified sand castings.
All of the following products were sand
castings.
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