The document describes the casting process and its key terms. It discusses the main steps: pattern making, mould preparation including gating and risering, core making, melting and pouring, and cleaning and inspection. It provides details on each step and describes how a mould is made by packing sand around a pattern. Common components produced by casting are also listed, such as automobile and aircraft parts. Advantages include the ability to make complex shapes easily and economically, while limitations include potential defects and inferior properties compared to other processes.

1. CASTING PROCESS
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2. Terms involved in casting
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3. Terms involved in casting process
• Mould box (flask) : It is usually a metallic
frame used for making and holding a sand
mould. The mould box has two parts: the
upper part called 'cope', and the lower
part called 'drag'.
• Parting line/parting surface: It is the zone
of separation between cope and drag
portions of the mould in sand casting.
• Sprue: It is vertical passage through which the molten metal
will enter the gate.
• Pouring basin: The enlarged portion of the sprue at its top
into which the molten metal is poured.
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4. Terms involved in casting process
• Gate/ingate: It is a short passage way which
carries the molten metal from the runner/
sprue into the mould cavity.
• Riser: A riser or feed-head is a vertical
passage that stores the molten metal and
supplies (feed) the same to the casting as it
solidifies.
• Gate/ingate: It is a short passage way which carries the molten metal from the
runner/ sprue into the mould cavity.
• Riser: A riser or feed-head is a vertical passage that stores the molten metal
and supplies (feed) the same to the casting as it solidifies.
• Mould cavity: The space in a mould that is filled with molten metal to form the
casting upon solidification.
• Core: A core is a pre-formed (shaped) mass of sand placed in the mould cavity
to form hollow cavities in castings.
• Core print: It is a projection attached to the pattern to help for support and
correct location of core in the mould cavity.7/28/2017 4

5. STEPS INVOLVED IN MAKING A CASTING
The basic steps in making a casting are:
(a) Pattern making
(b) Mould preparation (including gating and risering)
(c) Core making
(d) Melting and Pouring
(e) Cleaning and Inspection
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6. a) Pattern making
• A pattern is a replica of the object to be cast.
• It is used to prepare a cavity into which the molten
metal is poured.
• A skilled pattern maker prepares the pattern using
wood, metal, plastic or other materials with the help
of machines and special tools.
• Many factors viz., durability, allowance for shrinkage
and machining etc., are considered while making a
pattern.
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7. b) Mould preparation
• Mould preparation involves forming a cavity by packing
sand around a pattern enclosed in a supporting metallic
frame called 'flask' (mould box).
• When the pattern is removed from the mould, an exact
shaped cavity remains into which the molten metal is
poured.
• Gating and risering are provided at suitable locations in
the mould.
– Gating - Passage through which molten metal flows and enter the mould
cavity.
– Risering - A reservoir of molten metal connected to the mould cavity to
supply additional metal so as to compensate for losses due to shrinkage, as
the metal solidifies.
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8. c) Core making
• In some cases, a hole or cavity is required in the
casting.
• This is obtained by placing a core in the mould
cavity.
• The shape of the core corresponds to the shape
of the hole required.
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9. d) Melting and Pouring
• Metals or alloys of the required composition are
melted in a furnace and poured into the mould
cavity.
• Many factors viz., temperature of molten metal,
pouring time, turbulence etc., should be considered
while melting and pouring.
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10. e) Cleaning and Inspection
• After the molten metal has solidified and cooled, the
rough casting is removed from the mould, cleaned
and dressed.
• This involves removing cores, adhered sand particles,
gating and risering systems, fins, blisters etc., from
the casting surface.
• then sent for inspection to check for dimensions or
any defects like blow holes, cracks etc.
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11. Procedure for making the casting
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15. Components Produced by
Casting Process
• Casting is the first step and the primary process for shaping
any material.
• All materials have to be cast before it is put to use.
• The ingots produced by casting process are used as raw
material for secondary processes like machining, forging,
rolling etc.
• More than 90 % of all manufactured goods and capital
equipment use castings for their manufacture.
• To list the components produced by casting is an endless
process. A few major components produced by casting are
given below.
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16. Components Produced by Casting Process
• Automotive sector - Nearly 90 % of the parts in automobiles are-
manufactured by castings. A few parts include brake drum, cylinder,
cylinder linings, pistons, engine blocks, universal joints, rocker arm,
brackets etc.,
• Aircraft - Turbine blades, casing etc.
• Marine propeller blades.
• Machining - Cutting tools, machine beds, wheels and pulleys, blocks and
table for supports etc.
• Agriculture and rail road equipments.
• Pumps and compressors frame, bushings, rings, pinion etc.
• Valves, pipes and fittings for construction work.
• Camera frames, parts in washing machine, refrigerators and air-
conditioners.
• Steel utensils and a wide variety of products.
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17. Advantages of casting process
• Large hollow and intricate shapes can be easily cast.
• Quick process, and hence suitable for mass production.
• No limit to size and shape. Parts ranging from few millimeters to meters
and few grams to tons can be cast efficiently and economically.
• Better dimensional tolerances and surface finish can be obtained by
good casting practice.
• Castings exhibit uniform properties in all the directions - longitudinal,
lateral and diagonal.
• The casting process is usually the cheapest process.
• Unrelieved internal stresses are absent in cast components.
• Certain metals and alloys can be manufactured by means of casting only,
e.g., Phosphor-Bronze.
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18. Limitations of casting process
• Presence of defects in cast parts is a major disadvantage.
• Casting process is not economical for small number of parts.
• Properties of cast materials are generally inferior when
compared to those made by machining or forging process.
• Casting process mostly deals with elevated temperatures.
• There are limitations regarding thin sections.
• Casting process is not suitable for very small number of
components.
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