Sand Foundry in China
Sand foundry means the metal foundries,
who produce the iron, steel or aluminum
castings by sand molds. Sand foundries are very common in
the world, there are many sand foundries in China and India.
Sand foundries use different sands to produce different metal
castings. They use the green sand (greensand) to produce
iron castings, use the
dry quartz sand or water glass sand to produce
steel castings, and use the
very find sand to produce the aluminum castings. Green sand means
the sand contains a certain amount of moisture, which is the most
common material for the
casting process. In addition, there are some new types of
sand used for producing iron and steel castings, such as
resin sand and
pre-coated resin sand.
There are some common equipments in sand foundries. The sand mixing
equipments are used for mixing the sands, the molding machines are
used for making the sand molds, the cupolas or medium-frequency
induction furnaces are used for melting the metals, the sand
blasting machines are used to clean the sands on the surfaces of the
metal castings. Many sand foundries in China have their own
machining equipments to do the rough or finish machining.
Sand foundry has over 6000 years of history, and is the most common
metal foundries in the world. There are many advantages for sand
foundries, such as very low equipments investments, low material
costs, high production rate and comparatively simple production
technology. Moreover, sand foundries can produce very small and very
large sand castings.
However, there are also many disadvantages of sand foundries, such
as comparatively lower casting quality, rough surface smoothness,
many casting defects
(sand holes, air holes and cracks), sand residues, environment
pollution and high power assumption.
Moreover, because of the very poor working conditions, and high
physical force, it is difficult to find many skilled workers in sand
foundries. The shortage of manpower is dramatically affect the
development of sand foundry. Therefore, more and more sand foundries
in China are trying to import the automatic molding equipments to
replace the workers. However,
automatic molding lines have many dimensional, weight and
annual demand restriction, so they can not completely replace the
Since the metal castings are the base of civil products and
industries, so sand foundry must have a brighter development, but
just have to continuously improve the working conditions, worker
salaries, environments and production technologies.