Virtually nothing moves, turns, rolls, or flies without the benefit of cast metal products. The metal casting industry plays a key role in all the major sectors of our economy. There are castings in locomotives, cars trucks, aircraft, office buildings, factories, schools, and homes.

Casting is a manufacturing process in which material is first melted, sometimes treated for chemical composition, the molten material is then poured in a cavity of desired shape after which molten metal cools in the cavity and solidification takes place.

Once the material solidification is complete after sufficient cooling, the cast product is taken out of the cavity either by breaking the mould or  taking the mold apart and after that cleaning and further finishing operations are carried out.

After cleaning of casting, inspection of casting is done to check for defects if any.

History : 

Casting technology, according to biblical records, reaches back almost 5,000 years BC. Gold, pure in nature, most likely caught Prehistoric man's fancy…as he probably hammered gold ornaments out of the gold nuggets he found. Silver would have been treated similarly. Mankind next found copper, because it appeared in the ash of his camp fires from copper-bearing ore that he lined his fire pits with. Man soon found that copper was harder than gold or silver. Copper did not bend up when used. So copper, found a ‘nitch' in man's early tools, and then marched it's way into Weaponry. But, long before all this…man found clay. So he made pottery – something to eat from. Then he thought, "now…what else can I do with this mud…" . Early man thought about it, "they used this pottery stuff, ( the first patterns ), to shape metal into bowls ".

3200 B.C. A copper frog, the oldest known casting in existence, is cast in Mesopotamia.

233 B.C. Cast iron plowshares are poured in China.

500 A.D. Cast crucible steel is first produced in India, but the process is lost until 1750, when Benjamin Huntsman reinvents it in England.

1455 Dillenburg Castle in Germany is the first to use cast iron pipe to transport water.

1480 Birth of Vannoccio Biringuccio (1480-1539), the "father of the foundry industry," in Italy. He is the first man to document the foundry process in writing.

1709 Englishman Abraham Darby creates the first true foundry flask for sand and loam molding.

1750 Benjamin Huntsman reinvents the process of cast crucible steel in England. This process is the first in which the steel is completely melted, producing a uniform composition within the melt. Since the metal is completely molten, it also allows for alloy steel production,           as the additional elements in the alloy can be added to the crucible during melting. Prior steel production was accomplished by a combination of forging and tempering, and the metal never reached a molten state.

1809 Centrifugal casting is developed by A. G. Eckhardt of Soho, England.

1896 American Foundrymen's Association (renamed American Foundrymen's Society in 1948 and now called the American Foundry Society) is formed.

1897 Investment casting is rediscovered by B.F. Philbrook of Iowa. He uses it to cast dental inlays.

1947 The Shell process, invented by J. Croning of Germany during WWII, is discovered by U.S. officials and made public.

1953 The Hotbox system of making and curing cores in one operation is developed, eliminating the need for dielectric drying ovens.

1958 H.F. Shroyer is granted a patent for the full mold process, the forerunner of the expendable pattern (lost foam) casting process.

1968 The Coldbox process is introduced by L. Toriello and J. Robins for high production core making.

1971 The Japanese develop V-Process molding. This method uses unbonded sand and a vacuum.

1971 Rheocasting is developed at Massachusetts Institute of Technology.

1996 Cast metal matrix composites are first used in a production model automobile in the brake rotors for the Lotus Elise.

Metal Casting History (India)

3000 BC Earliest castings include the 11 cm high bronze dancing girl found at Mohen-jo-daro.

2000 BC Iron pillars, arrows, hooks, nails, bowls and daggers or earlier have been found in Delhi, Roopar, Nashik and other places.

500 BC Large scale state-owned mints and jewelry units, and processes of metal extraction and alloying have been mentioned in Kautilya's Arthashastra

500 A.D. Cast crucible steel is first produced in India, but the process is lost until 1750, when Benjamin Huntsman reinvents it in England

A sector wise casting consumption is given below which highlights the importance of casting in any industrial setup.

• Transport: Automobile, aerospace, railways and shipping
• Heavy Equipment: Construction, farming and mining
• Machine Tools: Machining, casting, plastics moulding, forging, extrusion and forming
• Plant Machinery: Chemical, petroleum, paper, sugar, textile, steel and thermal plants
• Defence: Vehicles, artillery, munitions, storage and supporting equipment
• Electrical Equipment Machines: Motors, generators, pumps and compressors
• Hardware: Plumbing industry pipes, joints, valves and fittings
• Household: Appliances, kitchen and gardening equipment, furniture and fittings
• Art Objects: Sculptures, idols, furniture, lamp stands and decorative items

1. Size : In principal any size of the component can be made by the casting process in a single piece. Size and weight of the product is not a limitation for the casting process.
2. Complexity : Most simple to most complex components can be made by the casting process. Because the molten material can flow into very small sections so that intricate shapes can be made by this process. As a result, many other operations, such as machining, forging, and welding can be minimized or eliminated.
3. Cost : Casting process is the cheapest process in most of the cases of production. As the metal can be placed exactly where it is required, a large saving in weight can be achieved.
4. Required Tools : The necessary tools required for casting moulds are very simple and inexpensive. As a result, for the production of a small lot, it is the ideal process.
5. Casting Material : It is possible to cast practically any material that is ferrous or non-ferrous. There are certain parts made from metals and alloys that can only be processed this way.

1. Dimensional accuracy and surface finish of the castings made by sand casting processes is a limitation to this technique. Many new casting processes have been developed which can take into consideration the aspects of dimensional accuracy and surface finish. Some of these processes are die casting process, investment casting process, vacuum-sealed moulding process, and shell moulding process.
2. The metal casting process is a labour intensive process

1. Pattern: It is the replica of the final object to be made. The mould cavity is made with the help of the pattern.
2. Bottom board: This is the board normaly made of wood and used at the begining of mould making process. The pattern is first kept on bottom board, sand is sprinkled on it,and then reaming is done in the drag.
3. Moulding sand: Sand, which binds strongly without losing its permeability to air or gases. It is a mixture of silica sand, clay, and moisture in appropriate proportions.
4. Flask: A metal or wood frame, without fixed top or bottom, in which the mould is formed. Depending upon the position of the flask in the moulding structure, it is referred to by various names such as
   • Drag – lower moulding flask,
   • Cope – upper moulding flask,
   • Cheek – intermediate moulding flask used in three piece moulding.
5. Parting line: This is the dividing line between the two moulding flasks that make up the mould.
6. Facing sand: The small amount of carbonaceous material sprinkled on the inner surface of the mould cavity to give a better surface finish to the castings.
7. Baking sand: This sand is made up of used and burnt sand. This constitutes the major portion of sand in sand moulding.
8. Core: A separate part of the mould, made of sand and generally baked, which is used to create openings and various shaped cavities in the castings.
9. Pouring basin: A small funnel shaped cavity at the top of the mould into which the molten metal is poured.
10. Sprue: The passage through which the molten metal, from the pouring basin, reaches the mould cavity. In many cases, it controls the flow of metal into the mould.
11. Runner: The channel through which the molten metal is carried from the sprue to the gate.
12. Gate: A channel through which the molten metal enters the mould cavity.
13. Chaplets: Chaplets are used to support the cores inside the mould cavity to take care of its own weight and overcome the metallostatic force.
14. Chills: Chills are metallic objects, which are placed in the mould to increase the cooling rate of casting, to provide uniform or desired cooling rate.
15. Riser: A column of molten metal placed in the mould to feed the castings as it shrinks and solidifies. Also known as “feed head”.
16. Vent: Small opening in the mould to facilitate the escape of air and gases.

As we begin to survey the various casting processes, it is helpful to have some form of process classification. One approach focuses on the moulds and utilises the following categories:

1. Conventional Sand Moulding Process
2. Chemical Sand Moulding Process
3. Multiple-use molds
4. Special Casting Processes

Categories 1 and 2 are often combined under the more general heading Sand-Mold Casting Processes, Sand, plaster, ceramics, or other refractory materials are combined with binders to form the mold.
Category 3 is covered under chapter Multiple-use mold Casting Processes. The multiple-use molds are usually made from metal.
Category 4 is covered under chapter Special Casting Processes.