Casting is a process by which a material is introduced into a mold
while it is liquid, allowed to solidify in the shape inside the mold,
and then removed producing a fabricated object or part. The
finished product is also called a casting.
Castings are used extensively in the automobile manufacture
industry, such as the casting of engine blocks or cylinder heads,
or vacuum-forming of plastics and in the lost core process.
Casting may be used to form hot, liquid metals or meltable
plastics (called thermoplastics), or various materials that cold set
after mixing of components such as certain plastic resins (e.g.
epoxy), water setting materials such as concrete or plaster, and
materials that become liquid or paste when moist such as clay,
which when dry enough to be rigid is removed from the mold,
further dried, and fired in a kiln.
A metal casting is a metal part formed by pouring molten metal
into a sand mold or metal die. The mold or die is comprised of two
halves that, when mated together, form a cavity into which the
molten metal is poured. The mold or die form the external surface
of the casting. If an internal cavity is required in the casting, a
core is placed inside the mold cavity.
After the metal solidifies, the mold is broken, the cores removed
and the part is readied for finishing operations. The sand is then
remolded and used again. When a metal die is used, the two
halves of the die are separated and the solidified casting is
removed. The die is then reused.
What metals can be cast?
Virtually any metal that can be melted can and is being cast in
foundries today. The most common alloys used in metal casting
are shown below. Metals are most commonly categorized as
ferrous or nonferrous.
What are castings used for?
Metal castings are used in several industrial applications. More
than 90% of all manufactured goods and capital equipment use
castings as engineered components or rely on castings for their
Casting in Manufacturing
Casting is a process by which a fluid melt is introduced into a
mold, allowed to cool in the shape of the form, and then ejected
to make a fabricated part or casing. Four main elements are
required in the process of casting: pattern, mold, cores, and the
part. The pattern, the original template from which the mold is
prepared, creates a corresponding cavity in the casting material.
Cores are used to produce tunnels or holes in the finished mold,
and the part is the final output of the process.
Substitution is always a factor in deciding whether other
techniques should be used instead of casting. Alternatives include
parts that can be stamped out on a punch press or deep-drawn,
items that can be manufactured by extrusion or by cold-bending,
and parts that can be made from highly active metals.
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