Introduction to Manufacturing Processes and their Applications (Casting, Forging, Sheet metal working and Metal joining processes). Description of the Casting process: Sand casting (Cope & Drag), Sheet metal Forming (shearing, bending, drawing), Forging (Hot working and cold working comparison), Electric Arc welding, Comparison of— Welding, Soldering, Brazing.

1. Basic Mechanical Engineering
By
Nitin G Shekapure
Unit III
Manufacturing Processes (L18 To L23)
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2. By: Nitin Shekapure
Unit III
Manufacturing Processes
Introduction to Manufacturing Processes and their Applications (Casting,
Forging, Sheet metal working and Metal joining processes). Description of
the Casting process: Sand casting (Cope & Drag), Sheet metal Forming
(shearing, bending, drawing), Forging (Hot working and cold working
comparison), Electric Arc welding, Comparison of— Welding, Soldering,
Brazing.
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3. Manufacturing – Need and concept
The progress and the prosperity of human civilization are governed and judged mainly
by improvement and maintenance of standard of living through availability or
production of ample and quality goods and services for men’s material welfare (MMW)
in all respects covering housing, clothing, medicine, education, transport,
communication and also entertainment. The successful creation of men’s material
welfare (MMW) depends mainly on
 Availability of Natural Resources (NR)
 Exertion of Human Effort (HE); both physical and mental
 Development and use of power tools and machines (Tools),
This can be depicted in a simple form,
MMW = NR(HE)TOOLS
where, NR: refers to air, water, heat and light, plants, animals, solid and liquid minerals
TOOLS: refers to power plants, chemical plants, steel plants, machine tools etc. which
magnify human capability.
This clearly indicates the important roles of the components; NR, HE and TOOLS on
achieving MMW and progress of civilization.
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4. Difference Between Manufacturing
and Production
The two phrases ‘to produce’ and ‘to manufacture’ are often considered
synonyms and are used as replacements for each other. Many a times, the
use of the two has actually ben interchanged.
However…But
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5. Manufacturing
Manufacturing is a process of producing something useful through raw
materials with the help of machinery or by hands in factories. The
term manufacturing is used in the industrial sector where the input is
transformed into the output on a large scale. The input can be in the form of
raw material, components, and parts.
The most important feature of manufacturing is the men-machine setup. The
product manufactured can either be directly sold to the final consumers or
other manufacturing entities to produce other items like equipment,
appliances, aircraft, household, etc.
Arrived from the Latin word “manu factus”, meaning “made by hand”.
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6. Production
The activity of transforming both material and non-material inputs into the
output that create utility is known as Production. The transformation
includes conversion of raw materials into work in progress and works in
progress into finished goods ready for sale. Here, the material input includes
raw material, components, partly finished goods, etc. and non-material goods
include ideas, information, skill, art, talent, etc.
The production of goods and services employs manpower and sometimes
machines. The output generated should be used for consumption, or it
must possess a value so that it can be sold to the consumer. In economics, the
production of goods and services is done to satisfy human wants. There are
five factors of production that are used in the activity; they are land, labor,
capital and entrepreneur. The participation and coordination of all these
factors can lead to a successful production.
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7. The following are the major differences between manufacturing and production:
• When the raw material is used as input to produce goods with the use of machinery is
known as a Manufacturing. The process of transforming resources into finished
products is known as Production.
• Manufacturing consists of the generation of all those goods that are suitable for use or
it can be sold out. On the other hand, production involves the creation of the utility.
• In manufacturing, the use of machinery is a must whereas production can be done with
or without the use of machinery.
• All types of manufacturing activities are used in production, but production may not
necessarily be known as manufacturing.
• In manufacturing, the output generated will be tangible in nature, i.e. goods only, but
in the case of production it produces both tangible and intangible outputs, i.e. goods as
well as services.
• Men-machine setup should be there for manufacturing of goods, which is not in the
case of production, the only man is sufficient for producing output.
Key Differences Between Manufacturing and Production
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8. So in simple way
Manufacturing is
The process of converting raw materials, components, or parts
into finished goods that meet a customer's expectations or
specifications.
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9. Classification of
Manufacturing Processes
Manufacturing
Processes
Cutting
Lathe
Drilling
Milling
Grinding
Shaping
Boring
Sawing
NC Machines
Gear Cutting
Finishing
Non- Cutting
Casting
Rolling
Forging
Press Work
Molding
Wire Drawing
Fabrication
Welding
Brazing
Soldering
Riveting
Screw Fastening
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10. Casting is a manufacturing process in which a liquid material is usually
poured into a mold, which contains a hollow cavity of the desired shape, and
then allowed to solidify. The solidified part is also known as a casting
Non Cutting
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11. Non Cutting
Casting
• Metal Casting is one of the oldest materials shaping methods known.
• Casting means pouring molten metal into a mold with a cavity of the shape
to be made, and allowing it to solidify.
• When solidified, the desired metal object is taken out from the mold either
by breaking the mold or taking the mold apart.
• The solidified object is called the casting.
• By this process, complex parts can be given strength and rigidity frequently
not obtainable by any other manufacturing process.
• The mold, into which the metal is poured, is made of some heat resisting
material.
• Sand is most often used as it resists the high temperature of the molten
metal. Permanent molds of metal can also be used to cast products.
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12. Types of Casting
1. Sand Casting
2. Investment Casting
3. Die Casting
4. Centrifugal Casting
Casting
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13. Features of casting process:
• Cast Components are brittle.
• Close dimensional controls are not expected
• No restriction on the size of the component
• No restriction on the type of metal or alloy used
• Surface finish is un satisfactory, Machining is required
• Extremely thin sections can not be cast
• Large variations in section thickness of components are not allowed
• Economically suitable for both job and mass production
Casting
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14. Applications of casting process
1. Automobiles
 Engine Blocks
 Cylinder blocks
 Pistons.
 Piston rings
 Clutch Housing, etc
2. Aircrafts
 Jet engine blades
 Gear box housing
 Gear blank, etc
 Pulleys.
3. Machine tool
 Machine tool beds
 Frames
 Gear box housing
 Gears
 Machine tool slides and heavy
components, etc
4. Water Pump Casings
5. Turbine casings
6. Flywheels
Casting
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15. Sand casting process
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16. Sand casting process
Castings are made by sand.
Applications- Gear box housing. Bearing housing, machine tool frame, etc.
Casting
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17. Metal Casting: Sand Casting
• Steps in Sand Casting:
1. Pattern Making:
• Pattern is replica of the part to be casted.
• Initially pattern has to be made using different manufacturing
process other than casting.
• Draft/Taper is provided on pattern for its easy removal from sand
mould
• Commonly used materials for
pattern making are-
Wood, Plastic and metal
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18. • Steps in Sand Casting:
2. Mould Making:
• Mould is a container made from green sand and which has cavity
in which molten metal can poured.
• Mould box has two splits, the upper one is called cope and lower
one is called drag
• Arrangement for metal pouring has to be made inside the mould
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19. • Steps in Sand Casting:
3. Core Making:
• Core is a device used in sand casting to produce hollow castings
• Generally core is made from same material as that of the mould
i.e. sand
• Supporting elements called chaplets are used to support core
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20. • Steps in Sand Casting:
4. Metal Melting and Pouring:
• The raw material is melted using furnace. Furnace may be
operated on electricity or fuel
• The molten metal is poured into mould using ladle
• Pouring basin, sprue, runner, gate are used to guide molten
metal into the cavity
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21. • Steps in Sand Casting:
5. Solidification
• Metal is allowed to cool to room temperature
• During solidification the metal shrinks and the extra metal
required compensate this shrinkage is obtained from the riser
6. Finishing
• Undesired part which corresponds to gating system and riser
has to be cut from main casting
• The casted surface generally is rough and some finishing
operation like grinding, machining, polishing are required
7. Inspection
• Before dispatching the casted part has to be checked for
desired dimensions. The part which doesn’t meet expected
dimensions has to be scraped
• Castings are also checked for various undesirable defects
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22. Sand casting terms
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23. Steps in Sand casting
1
2
3 4 5 6
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24. Advantages of sand casting
• Complex shapes component can be produced
• Highly economical & cost of component is very low
• Not require high initial investments
• Not required highly skilled man power
• Suitable for small job production
Casting
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25. Limitations of sand casting
• Poor dimensional accuracy.
• It involves melting of metal, high energy consumption process.
• Not suitable for highly complex shapes
• Can not produce extremely thin sections. (less than 6 mm)
• For each casting requires one mould hence this process requires
large man power for mould making
• Large working space, in addition storing raw material, installing
furnace & molding sand
• Environmental pollution is high.
Casting
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26. Sand Casting
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27. Die Casting
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28. Investment Casting
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29. Centrifugal Casting
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30. Non Cutting
Rolling Is the process of plastically deforming metal by
passing it between rolls.
Is widely used to convert steel ingots into blooms, billets, and slabs, and
subsequently into plates, sheets and strips
Advantages
• Provides high throughput (Material)
• Provides good control over the dimensions of
the finished product
In Hot Rolling:
• Metal is rolled at a temperature above its recrystallization temperature
• Higher reduction in the cross-section is achieved
In Cold Rolling:
• Metal is rolled at a temperature below its recrystallization temperature
• Better strength and control of dimensions are achieved
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31. Non Cutting
Forging is a metal forming process in which metal is first heated and
then plastically deformed to the desired shape and size by the application of
compressive force using hand hammer, or a press
Ductile materials are required. (ability of material to sustain plastic
deformation without failure.)
• Alloy Steel, Low Carbon Steel, Medium Steel, Stainless steel
• Copper Alloys
• Aluminum Alloys etc.
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32. Two types of Forging by working process
• Hot Forging: It is Defined as the deformation of the material into
predetermined shape carried out at a temperature above its
recrystallation temperature
• Cold Forging: It is Defined as the deformation of the material into
predetermined shape carried out at a temperature below its
recrystallation temperature (usually room temperature).
Forging
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33. Difference between Cold & Hot Working Forging
Parameters Hot Working Forging Cold Working Forging
Force & Energy
required
Low High
Dimensional accuracy
Poor (due to thermal
contraction during cooling)
Good
Machine
requirement
Light Heavier and Powerful
Ductility of
component
Increases Decreases
Type of materials Need not be soft Soft like Aluminum
Strain Hardening
effect
Absent Present
Forging
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34. Types of Forging
 Hammer Forging
 Drop Forging
 Press Forging
 Upset Forging
 Roll Forging
Forging
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35. • Open-Die Forging
• Oldest Style
• Free Fall or Steam Driven
• Low Rate and Accuracy
 Hammer Forging
Pressure or load applied on hot metal part by hand
Forging
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36.  Drop Forging
• Aligned Cavity Dies
• Horizontal Impact Forging
• High Accuracy
• High Tensile Strength
Forging
Pressure or load applied on hot metal part by impacting ram.
Ram is fall under gravity from certain height
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37. Press Forging
• Large Forgings Produced
• Slow, Steady Pressure
• Uniform Deformation
• Mechanical or Hydraulic
Forging
The hammering action is relatively slow squeezing instead of delivering
heavy blows
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38. Upset Forging
• Machine Forging
• Common
• Hot or Cold
Forging
The cross section of the hot material or workpiece is increased locally
with a corresponding reaction in it’s length by slow squeezing action.
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39.  Roll Forging
• Fast
• Widely Used
• Long, Tapered or Symmetrical Sections
Forging
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40. Forging
Forging
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41. Advantages
• High dimensional accuracy and good surface finish.
• Forging process reduces the grain size, which improve the
strength and toughness of the forged components.
• Thin sections are possible without reducing strength, which
results in light weight components.
• Produces the components without shrinkage cavities, blow
holes, machining scratches, which increases the endurance
strength.
• Better withstand the external load.
• Better resistance to shock and vibrations.
Forging
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42. Limitations
Applications
• Brittle materials can not be used.
• Complex components with intricate shapes can be produced
by casting and not by forging process.
• Forged component cost is more than cast components.
• Cost of forging dies is high.
• I C Engine parts like crankshafts, connecting rods, rocker arms, etc.
• Small tools
• Gear blanks, Levers.
• Automobile and Aircraft components.
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43. Sheet Metal Working is the process of manufacturing the
components from the sheet metal of thickness ranging from 0.1 mm to about
8 mm.
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44. Sheet Metal Working
Sheet Metal Cutting (Shearing) Operations
• Punching (Piercing)
• Punching
• Blanking
• Perforating
• Notching
• Lancing
• Slitting
Sheet Metal Forming Operations
• Bending
• Drawing & Deep Drawing
• Embossing
• Forming
• Coining (Squeezing)
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45. Metal Cutting (Shearing ) Processes
Piercing Producing a hole of any desired shape in metal.
Punching Producing a circular hole in metal
Blanking The metal punched out is the required component, called blank.
Sheet Metal Cutting Processes
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46. Metal Cutting (Shearing) Processes
Notching Removal of a small part of a metal sheet of any desired shape
Perforating Producing no of evenly spaced holes in a metal sheet
Sheet Metal Cutting Processes
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47. SlittingCutting a metal sheet in a straight line along a length
Metal Cutting (Shearing ) Processes
Lancing Cutting a part of metal sheet through some portion of its
length and then bending of cut portion
Sheet Metal Cutting Processes
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48. Metal Forming Processes
It is a process in which flat plate metal sheet is converted into a
desired shape without wasting the material.
 Drawing and deep drawing
 Bending
 Forming
 Coining
 Embossing
Sheet Metal Forming Processes
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49. V Bending
U Bending
Bending Methods
Sheet Metal Forming Processes
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50. Angle Bending
Bending and wiping/ Edge
bending
Sheet Metal Forming Processes
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51. Forming Process of flat metal sheet into a surface of a desired profile
Sheet Metal Forming Processes
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52. Curling an edge of circular cross section is formed along a sheet or at the
end of the tube.
Sheet Metal Forming Processes
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53. Embossing is the process producing depressed or raised impression of
letters figures or designs on metal sheet.
Sheet Metal Forming Processes
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54. Coining (Squeezing) is the process of cold squeezing of metal
sheet in which all the surface are confined within a set of dies.
Metal Forming Processes
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55. Metal Forming Processes
Wire drawing is a metalworking process used to reduce the cross-
section of a wire by pulling the wire through a single, or series
of, drawing die(s).
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56. Sheet Metal Working
Advantages
• Components produced are light in weight
• Cheap
• Rate of production is high
• High dimensional accuracy
• Not required skilled man power
Limitations
• Limitation of thickness of metal sheet
• Components have low strength
• Not suitable for job production
• Vibrations are more during operations
• Noisy in operation
• Dies are costly
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57. Applications
Sheet Metal Working
• Automobile body parts (bike , car , buses etc), aircraft body parts.
• Steel furniture, Utensils
• Electronics appliancesN
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58. • Joining includes welding, brazing, soldering, adhesive
bonding of materials.
• They produce permanent joint between the parts to be assembled.
• They cannot be separated easily by application of forces.
• They are mainly used to assemble many parts to make a system.
Joining of materials
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59. Welding is a materials joining process which produces
merging of materials by heating them to suitable
temperatures with or without the application of pressure or
by the application of pressure alone, and with or without the
use of filler material.
Welding
Welding
AWS distinguishes the welding processes according to:
• Mode of energy transfer
• Influence of capillary attraction in effecting distribution of filler metal in
the joint
The American Welding Society
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60. Advantages of welding
Welding
• Welding provides a permanent joint.
• Welded joint can be stronger than the parent materials if a proper
filler metal is used that has strength properties better than that of
parent base material and if defect less welding is done.
• It is the economical way to join components in terms of material
usage and fabrication costs. Other methods of assembly require,
for example, drilling of holes and usage of rivets or bolts which will
produce a heavier structure.
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61. Welding
Disadvantages of welding
• Labour costs are more since manual welding is done mostly
• Dangerous to use because of presence of high heat and pressure
• Disassembly is not possible as welding produces strong joints
• Some of the welding defects cannot be identified which will reduce
the strength
• Heat generated due to welding produces metallurgical
changes hence, the structure of welded joint is different than that
of parent metal.
• Before welding, generally edge preparation of the workpieces is
required
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62. Welding
Applications of welding
Some of the important applications of welding process are as follows :
• Aircraft construction (Welding of engine parts, turbine frame, ducts, etc.)
• Rail-road equipment's (Air receiver, engine, front and rear hoods, etc.)
• Pipings and pipelines (Open pipe joints, oil and gas pipelines, etc.).
• Pressure vessels (boilers) and tanks Qoining of nozzles, ends, tanks, etc.).
• Buildings and bridges (Columns base plates, erection of structures, etc.).
• Automobile parts (Trucks, buses, cars, cranes, bikes parts, etc.).
• Machine parts (Frames, beds, tools, dies, etc.).
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63. Types of Welding Joint
Welding
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64. Groups of welding processes
• Electric Arc welding
• Brazing
• Oxyfuel Gas Welding
• Resistance Welding
• Solid State Welding
• Soldering
• Other
Welding
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65. There are different ways of classifying welding and allied processes.
Modern methods of welding may be classified under two broad
categories i.e. plastic (Pressure) welding and fusion (non-pressure) welding.
Classification of Welding processes
In general, welding and allied processes are classified as follows
Arc welding :
1. Gas tungsten arc welding (TIG)
2. Gas metal arc welding (MIG)
3. Electro-slag welding
4. Stud arc welding
5. Shielded metal arc welding
6. Submerged arc welding
7. Plasma arc welding
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66. Resistance welding :
1. Spot welding
2. Seam welding
3. Projection welding
4. Percussion welding
5. Resistance butt welding
Gas welding:
1. Oxy-acelylene welding
2. Oxy-hydrocarbon welding
3. Air acetylene welding
4. Pressure gas welding
Classification of Welding processes
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67. Welding
• Pressure Welding (Plastic Welding)
 In this process, metal pieces to be welded are heated to a temp. so as
to make them plastic and then forced together by external pressure.
 This process does not require additional metal for completing the
weld.
 For example, forge welding, electric resistance welding, etc.
• Fusion Welding (Non-Pressure Welding):-
 In this process, metal pieces to be welded are heated to molten (fusion)
state & allowed to solidify.
 No pressure is required in this process.
 Additional metal is generally supplied by filler rod (welding rod) to
complete the joint.
 For example, arc welding, gas welding, etc.
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68. Arc Welding
Electric Arc Welding
• It is a fusion welding process, in which welding heat is obtained from an
electric arc between electrode & work.
• The electrode is first allowed to touch the work to form an electric circuit
and then separated by a small distance ( 4 to 6 mm), so that current
continuous to flow through the gaseous medium.
• The temp. produced by an electric arc is about 5500 °C.
• The base metal is melted by the temp. of the arc, forming a pool of molten
metal which is forced out of the pool by blast from the arc.
• Metal of the electrode also gets melted & deposited at the weld.
• Either A.C. or D.C. is used for arc welding.
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69. Electric Arc Welding
Arc Welding
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70. Arc Welding
Advantages, Disadvantages and Applications of Arc Welding Process
Advantages
• It is the most versatile process which can be applied for thin and thick
sections.
• Welding of complicated shapes can also be done.
• Welding can be done in any position with high weld quality.
• Very neat appearance and smooth weld shapes can be obtained.
• Generally, edge preparation is not required.
• The equipment's are portable and less expensive.
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71. Arc Welding
Disadvantages
• As the electrodes are coated, the chances of slag entrapment and their
related defects are more.
• Welding control is difficult.
• The process needed filler material.
• It is a slow process.
Applications
Arc welding is commonly used in the manufacturing of following parts :
• Air receiver, boilers, pressure vessels fabrication.
• Automobile, chemical and aircraft industry.
• Ship buiding and bridge construction.
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72. Arc Welding
Types of Arc welding :
The main types of welding process are as follows
1. Shielded metal arc welding
2. Gas tungsten arc welding (TIG)
3. Gas metal arc welding (MIG)
4. Electro-slag welding
5. Plasma arc welding
6. Stud arc welding
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73. Arc Welding
Shielded Metal Arc Welding (SMAW) Process
It is also called as Flux shielded metal arc welding and as
Manual Metal Arc welding (MMA or MMAW)
 SMAW is an arc welding process where coalescence (blend) is produced by
heating the workpiece with an electric arc set up between the flux coated
electrode and the workpiece.
 Due to arc heat, the flux covering decomposes and performs functions of arc
stability, weld metal protection, etc.
 The electrode itself melts and supplies the necessary filler metal.
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74. Arc Welding
Shielded Metal Arc Welding (SMAW) Process
Principle
• Required heat for welding is obtained from the arc struck between the
coated electrode and the workpiece.
• By employing higher or lower currents, the arc temperatures and thus arc
heat can be increased or decreased.
• Generally, the arc temperature is about 2400 °C to 2600 °C
• A high current with a smaller arc length produces very intense heat.
• The arc melts the electrode and the workpiece.
• Material droplets are transferred from the electrode to workpiece through
the arc and are deposited along the welded joint.
• The coating of flux melts and produces a gaseous shield and slag to prevent
atmospheric contamination of the molten weld metal.
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75. Arc Welding
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76. Arc Welding
Shielded Metal Arc Welding (SMAW) Process
Advantages
• It is the simplest of all arc welding processes.
• The equipment is portable and less expensive.
• Various metals and their alloys can be welded.
• Welding can be done in any position with high weld quality
Limitations
• Due to limited length of electrode and brittle flux coating on it,
mechanization is difficult.
• It is a slow process.
• Because of flux coated electrodes, the chances of slag entrapment and other
related defects are more.
• Welding control in this process is difficult.
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77. Arc Welding
Shielded Metal Arc Welding (SMAW) Process
Applications
1. Used for all commonly used metals and their alloys.
2. It is used as a fabrication process and for maintenance and
repair jobs.
3. Also used in,
• Air receiver, boiler and pressure vessel fabrications
• Automotive and aircraft industry
• Ship building and bridge construction.
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78. Arc Welding
Gas Tungsten Arc Welding (GTAW) Process (TIG)
• It is also called as Tungsten Inert Gas (TIG) Welding.
• It is an arc welding process where coalescence (blend) is produced
by heating the workpiece with an electric arc struck between tungsten
electrode and workpiece.
• To avoid atmospheric contamination of the molten weld pool, a
shielding gas is used.
• If required, a filler metal may be added.
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79. Arc Welding
Gas Tungsten Arc Welding (GTAW) Process
Principle
• To start the process, welding current, water and inert gas supply are turned on.
• The arc is struck by touching the electrode with a scrap metal tungsten piece.
• Then the welding torch is brought near to the workpiece.
• When electrode tip reaches within a distance of 2 to 3 mm from the workpiece,
spark jumps across the air gap between the electrode and the workpiece.
• Then the air path gets ionised and arc is established.
• The welding continues by moving the torch along the joint and at the far end of
the workpiece arc is broken by increasing the air gap.
• To avoid atmospheric contamination, a shielding gas is impinged on the
solidifying part for a few seconds.
• The welding torch and the filler rod are generally kept inclined at an angle of 70°
to 80° with weld plane.
• For welding, a leftward technique is used.
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80. Arc Welding
Gas Tungsten Arc Welding (GTAW) Process
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81. Arc WeldingGas Tungsten Arc Welding (GTAW) Process
• No flux is used; hence there is no danger of flux entrapment.
• The operator can exercise a better control on the welding process as
there is clear visibility of the arc and the workpiece.
• This process produces smooth and sound welds with fewer spatters.
• No weld cleaning is required.
• It produces high quality welds in non-ferrous metals.
Advantages
• Cost of equipment is very high.
• By chance, if a filler rod end comes out of the inert gas shield, then it
can cause weld metal contamination.
• It is a slow process.
• Separate filler rod is required.
Disadvantages
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82. Arc WeldingGas Tungsten Arc Welding (GTAW) Process
Applications
• Welding of sheet metal and thinner sections.
• Precision welding in aircraft, chemical and instrumental industries.
• Welding of expansion bellows, instrument diaphragms and transistor
cases.
• Welding of Al, Mg, Cu, Ni and their alloys, alloy of stainless steel, etc.
N
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Shekapure

83. Arc Welding
Gas Metal Arc Welding (GMAW) Process (MIG)
• This process is also called as Metal Inert Gas (MIG) Welding.
• It is an arc welding process where coalescence (blend) is produced
by hearing the workpiece with an electric arc generated between a
continuously fed metal electrode and the workpiece.
• Flux is not used, but the arc and molten metal are shielded by an inert
gas.
• The inert gas may be argon, helium, carbon dioxide or a gas mixture.
N
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Shekapure

84. Arc WeldingGas Metal Arc Welding (GMAW) Process
Principle
* In this process, the wire is fed continuously from a reel through a gun at constant
rate, which also imparts current to the wire.
* The current ranges from 100 to 400 Amp. depending upon the wire diameter and
melting point of the wire.
* Depending upon the current being used, the welding gun can be either air or
water cooled.
* Bare electrodes are generally used for MIG welding.
* The electrode wire is generally in diameters of a 0.09 to 1.6 mm however sizes up
to 3.2 mm are made.
* In MIG welding, the welding area is flooded with an inert gas which will not
combine with the metal.
* The flow rate of this gas flow is sufficient to keep oxygen of the air away from the
non-metallic surface while welding is being done.
N
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Shekapure

85. Arc Welding
Gas Metal Arc Welding (GMAW) Process
N
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Shekapure

86. Arc WeldingGas Metal Arc Welding (GMAW) Process
• Because of continuously feeding electrode, it is a faster process.
• It can produce joint with deep penetration.
• Both thin and thick workpieces can be welded.
• Higher metal deposition rates are achieved by using MIG welding and this
processcan be easily mechanised.
• As flux is not used, MIG welding produces smooth, neat, clean and
• spatter free welded surfaces.
Advantages
Disadvantages
• This process is more complicated.
• Welding equipments are more complex, costly and less portable.
• As air drafts may disperse the shielding gas, MIG welding is not used for
outdoor applications.
N
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Shekapure

87. Arc Welding
Gas Metal Arc Welding (GMAW) Process
• For welding of tool steels and dies.
• For manufacturing of refrigerator parts
• Also used in industries such as aircraft, automobile, pressure vessel
and ship building.
• Welding of carbon, silicon and low alloy steels, stainless steels, Al, Mg, Cu,
Ni and their alloys can be done.
Applications
N
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Shekapure

88. Arc Welding
Comparison between TIG and MIG Welding Processes
Sr.No. TIG MIG
1. Non consumable electrodes are used. Consumable electrode wires are used.
2 Electrodes are made of tungsten
or tungsten alloys.
Bare welding wire is made of desired
composition.
3. Electrode only generates an arc and
does not melt.
Electrode generates an arc and melt also.
4. Easier for thin plates and small parts. Widely used for thick plates (above 4 mm).
5. Welding torch is water cooled. Welding torch is air or water cooled.
6. Used for joining dissimilar metals. Used for joining similar metals.
7. It is a slow process. It is a faster process.
8. During the process, separate filler
material is used.
In this process, metal electrode will act
as a filler material.
9. Cost of equipment is low. Cost of equipment is high.
N
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Shekapure

89. Brazing
It is a joining process in which a filler metal is melted and distributed by
capillary action between the faying (contact) surfaces of the metal
parts being joined.
Base material does not melt in brazing, only the filler melts.
In brazing, the filler metal has a melting temperature (liquidus) above
450°C, but below the melting point (solidus) of base metals to be
joined.
Brazing
N
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Shekapure

90. Filler materials used for brazing
Brazing
N
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Shekapure

91. Advantages of brazing
• Brazing can be used to join a large variety of dissimilar metals.
• Pieces of different thickness can be easily joined by brazing
• Thin-walled tubes & light gauge sheet metal assemblies not
joinable by welding can be joined by brazing.
• Complex & multi-component assemblies can be economically
fabricated with the help of brazing.
• Inaccessible joint areas which could not be welded by gas metal or
gas tungsten arc spot or seam welding can be formed by brazing.
Brazing
N
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Shekapure

92. Application of brazing
• Fabrication of heat exchangers, pipe fitting, electric repair
work.
• Joining of carbid tips with mild steel shanks in cutting tool
• Steam turbine
• Joining dissimilar material
• Joining non-metals to metals
Brazing
N
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Shekapure

93. Soldering
Soldering
• Soldering is similar to brazing and can be defined as a joining process
in which a filler metal with melting point (liquidus) not exceeding
450°C is melted and distributed by capillary action between the
faying surfaces of the metal parts being joined.
• As in brazing, no melting of the base metals occurs, but the filler
metal wets and combines with the base metal to form a
metallurgical bond.
• Filler metal, called Solder, is added to the joint, which distributes
itself between the closely fitting parts.
N
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Shekapure

94. Advantages of Soldering
• Soldering can be used to join a large variety of dissimilar metals.
• In soldering process, the temperature is below the melting
temperature of the workpiece, so there is no radical change in
mechanical properties of the workpiece
• Soldering can join the worpieces of different thinkness
• Process is simple and chipper than brazing
• Soldering joint require no finishing
Soldering
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Shekapure

95. Application of Soldering
• For joining the components of electric circuits.
• For joining thin sheets which are not subjected to load
• Soldering can join the worpieces of different thinness
• For joining the wires
Soldering
N
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Shekapure

96. N
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Shekapure

97. MCQ:
1. The manufacturing process can be defined as the
a) Process of converting the semi finished product into finished product
b) Process of converting the raw material into finished product using machines
c) Process of assembling the components into a product
d) Process of creating new product
N
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Shekapure

98. MCQ:
2. The process in which molten metal is poured into mould of desired
shape is called as
a) Metal forming
b) Metal forging
c) Casting
d) Injection moulding
N
itin
Shekapure

99. MCQ:
3. The following material is not suitable for casting
a) Aluminium
b) Plastic
c) Copper
d) Alloy steel
N
itin
Shekapure

100. MCQ:
4. The following material is suitable for casting
a) Aluminium alloy
b) Cast iron
c) Copper alloy
d) All of the above
N
itin
Shekapure

101. MCQ:
5. The example of component manufactured by casting is
a) Machine tool bed
b) Nut
c) Shaft
d) Ball bearing
N
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Shekapure

102. MCQ:
6. The following component cannot be manufactured by casting
a) Flywheel
b) Gears
c) Machine tool bed
d) Connecting rod
N
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Shekapure

103. MCQ:
7. The metal forming process is also known as
a) Deformation process
b) Casting process
c) Metal cutting process
d) All of the above
N
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Shekapure

104. MCQ:
8. In metal forming process
a) A molten metal in semifinished condition is converted to finished product.
b) A molten metal is poured into the mould of desired shape.
c) A metal in hot or cold condition is plastically deformed into desired shape.
d) B and c
N
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Shekapure

105. MCQ:
9. The following is not a metal forming process
a) Forging
b) Casting
c) Rolling
d) Drawing
N
itin
Shekapure

106. MCQ:
10. The following is a metal forming process
a) Casting
b) Turning
c) Forging
d) All of the above
N
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Shekapure

107. MCQ:
11. The ________is an example of a metal forming process
a) Forging
b) Rolling
c) Drawing
d) All of the above
N
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Shekapure

108. MCQ:
12. The following component cannot be manufactured by metal forming
process
a) Connecting rod
b) Machine tool bed
c) I-sections
d) Crankshaft
N
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Shekapure

109. MCQ:
13. In metal forming process,
a) Substantial material is removed from the raw material to convert it to
finished product.
b) Fine material is removed from the semifinished raw material to convert it
to finished product.
c) No material is removed from the raw material.
d) The removed material can be processed again and reused,
N
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Shekapure

110. MCQ:
14. The following is an example of metal forming process
a) Milling
b) Forging
c) Shaping
d) Grinding
N
itin
Shekapure

111. MCQ:
15. The following is an example of metal cutting process
a) Drilling
b) Forging
c) Grinding
d) Extrusion
N
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Shekapure

112. MCQ:
16. The metal cutting process is also known as _______
a) Machining
b) Metal forming
c) Metal deformation
d) All of the above
N
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Shekapure

113. MCQ:
17. The __________is a metal cutting process
a) Forging
b) Grinding
c) Turning
d) All of the above
N
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Shekapure

114. MCQ:
18. In casting process the cavity is called as
a) Cast
b) Pattern
c) Mold
d) Drag
N
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Shekapure

115. MCQ:
19. The components of intricate shape can be easily manufactured by
a) Forging
b) Casting
c) Sheet metal working
d) Grinding
N
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Shekapure

116. MCQ:
20. A component obtained by pouring the molten metal into a mould and
allowing it to solidify, is called
a) Mold
b) Pattern
c) Casting
d) Cope
N
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Shekapure

117. MCQ:
21. A plant where the castings are produced is called
a) Machine shop
b) Foundry
c) Mould shop
d) Casting plant
N
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Shekapure

118. MCQ:
22. ________ is the upper part of the casting flask
a) Drag
b) Cope
c) Mold
d) Pattern
N
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Shekapure

119. MCQ:
23. Cope is the ________
a) Mould cavity
b) Casting
c) Lower part of the casting flask
d) Upper part of the casting
N
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Shekapure

120. MCQ:
24. Drag is the ________
a) Mould cavity
b) Lower part of the casting flask
c) Upper part of the casting
d) Pattern
N
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Shekapure

121. MCQ:
25. Find the odd term out from the following
a) Drag
b) Cope
c) Pull
d) Foundry
N
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Shekapure

122. MCQ:
26. Which of the following statement is incorrect ?
a) Casting can produce components of high strength.
b) Casting can produce components of intricate shapes.
c) Casting produce gas cavities and blow holes inside the component.
d) Aluminium components can be produced by casting process.
N
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Shekapure

123. MCQ:
26. In_________ process, environmental pollution is high
a) Forging
b) Casting
c) Machining
d) None
N
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Shekapure

124. MCQ:
27. I.C. engine blocks are manufactured by
a) Forging
b) Casting
c) Shaping
d) Both a and b
N
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Shekapure

125. MCQ:
28. The first step in casting process is
a) Mould making
b) Core making
c) Pattern making
d) Pouring of metal
N
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Shekapure

126. MCQ:
29. _______ is the replica of casting, used for making a cavity
a) Mold
b) Workpiece
c) Pattern
d) Cope
N
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Shekapure

127. MCQ:
30. In casting process, the pattern is nothing but
a) A final component produced.
b) A mould made from sand.
c) The replica of a casting used for making the mould.
d) A design on the component
N
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Shekapure

128. MCQ:
31. The following statement about casting process is correct
a) The pattern is made by using mould.
b) The final cast component is converted to pattern by machining process.
c) The mould is made by using pattern.
d) The pattern is required only for complicated shapes for comparison
N
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Shekapure

129. MCQ:
32. In sand casting, the pattern is made from
a) Sand
b) Clay
c) Plaster of pans
d) Wood
N
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Shekapure

130. MCQ:
33. The following material cannot be used for pattern
a) Wood
b) Hastic
c) Aluminium
d) Sand
N
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Shekapure

131. MCQ:
34. The process of making the model of a casting used for making a cavity
or mould is called as
a) Molding
b) Modeling
c) Pattern making
d) Casting
N
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Shekapure

132. MCQ:
35. In casting process, the mould is commonly made from
a) Sand
b) Cast iron
c) Wood
d) Plastic
N
itin
Shekapure

133. MCQ:
36. In casting process, the mould is commonly made from
a) Mold making
b) Pattern making
c) Core making
d) Cope making
N
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Shekapure

134. MCQ:
37. In casting, the material used for mould making is
a) Cast iron
b) Aluminium
c) Sand
d) Wood
N
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Shekapure

135. MCQ:
38. In casting, the process of making a cavity which conforms to the shape
of the desired component is called as
a) Mold making
b) Cavitation
c) Pattern making
d) Case making
N
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Shekapure

136. MCQ:
39. In casting process, the holes or hollow spaces are obtained by using
a) Drills
b) Core
c) Moulds
d) Cavaties
N
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Shekapure

137. MCQ:
40. The furnace is essential for the following process
a) Forging
b) Shaping
c) Casting
d) None of the above
N
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Shekapure

138. MCQ:
41. The molten metal is required in
a) Forging
b) Shaping
c) Casting
d) None of the above
N
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Shekapure

139. MCQ:
42. _____________is a hole cut in a moulded sand to permit the molten
metal to rise above the highest point in the casting.
a) Riser
b) Runner
c) Cavity
d) Basin
N
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Shekapure

140. MCQ:
43. From pouring basin, the molten metal is carried to the mould cavity
through the _______
a) Riser
b) Runner
c) Cope
d) Pipe
N
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Shekapure

141. MCQ:
44. ________ helps in escaping of the air, gas and steam from mould cavity
a) Ventilator
b) Runner
c) Riser
d) Both b and c
N
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Shekapure

142. MCQ:
45. In sand casting process, the metal is melted in
a) Furnace
b) Boiler
c) Oven
d) All of the above
N
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Shekapure

143. MCQ:
46. The sequence of steps in casting process is
a) Core making - mould making - pattern making
b) Mould making - core making - pattern making
c) Pattern making - mould making - core making
d) Mould making - pattern making - core making
N
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Shekapure

144. MCQ:
47. The following statement is incorrect
a) The components produced by sand casting have poor dimensional accuracy.
b) The sand casting can produce extremely thin sections.
c) In sand casting, each casting requires one mould.
d) The components produced by sand casting have poor surface finish.
N
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Shekapure

145. MCQ:
48. The following statement is correct:
a) The sand casting can produce components with good dimensional accuracy.
b) The sand casting can produce extremely thin sections.
c) The sand casting process requires furnace.
d) All (a), (b) and (c).
N
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Shekapure

146. MCQ:
49. In sand casting, core is made of
a) Steel
b) Wood
c) Cast iron
d) None of the above
N
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Shekapure

147. MCQ:
50. In metal forming process, the component of desired shape and size is
obtained through
a) Pouring of molten metal in to cavity
b) Machining of material
c) Elastic deformation of metal
d) Plastic deformation of metal
N
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Shekapure

148. MCQ:
51. For metal forming process
a) Force is necessary
b) Both force as well as heat are necessary
c) Heat is necessary
d) Both force as well as heat are not necessary
N
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Shekapure

149. MCQ:
52. The following is not an example of metal forming process
a) Extrusion
b) Bending
c) Forging
d) Shaping
N
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Shekapure

150. MCQ:
53. The process performed by blacksmith is known as
a) Casting
b) Shaping
c) Rolling
d) Forging
N
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Shekapure

151. MCQ:
54. The forging operation is performed under
a) Breaking range of material
b) Elastic state of material
c) Plastic state of material
d) Molten state of material
N
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Shekapure

152. MCQ:
55. In _________ process, the material is deformed to desired size and shape
by the sudden application of force.
a) Casting
b) Forging
c) Metal cutting
d) Both a and b
N
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Shekapure

153. MCQ:
56. The plasticity of material plays important role is _______ process
a) Forging
b) Casting
c) Metal cutting
d) welding
N
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Shekapure

154. MCQ:
57. In forging process, the material deforms
a) Due to fracture
b) Due to melting
c) Without fracture
d) Both b and c
N
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Shekapure

155. MCQ:
58. In ancient days, the implements of war such as : swords, knives, arrows
were made by
a) Casting process
b) Shaping process
c) Forging process
d) Both b and c
N
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Shekapure

156. MCQ:
59. The forging process requires application of
a) Tensile force
b) Compressive force
c) Shear force
d) Constant force
N
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Shekapure

157. MCQ:
60. In forging press, _________is fixed.
a) Upper die
b) Lower die
c) Ram
d) Both b and c
N
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Shekapure

158. MCQ:
61. The mechanical press is used in ___________ operation
a) Forging
b) Casting
c) Machining
d) None of the above
N
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Shekapure

159. MCQ:
62. The material used for forging process
a) Must be the brittle material
b) Must be the ductile material
c) Can be ductile or brittle material
d) Must be the ferrous
N
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Shekapure

160. MCQ:
63. The process used by blacksmith is
a) Drop forging
b) Casting
c) Press forging
d) None of the above
N
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Shekapure

161. MCQ:
64. The die and punch are used in
a) Casting
b) Punching
c) Sheet metal work
d) Both b and c
N
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Shekapure

162. MCQ:
65. The sheet-metal work is carried out at ______ temperature
a) Recrystallization
b) Melting
c) 100°C
d) Room
N
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Shekapure

163. MCQ:
66. Piercing is similar to ______________
a) Blanking
b) Punching
c) Slitting
d) Notching
N
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Shekapure

164. MCQ:
67. The nameplates can be manufactured by the process known as
a) Coining
b) Forming
c) Blanking
d) Embossing
N
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Shekapure

165. MCQ:
68. In welding process, the essential elements is /are
a) Filler material
b) Pressure
c) Heat
d) Both a and c
N
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Shekapure

166. MCQ:
69. The welding is used in
a) Manufacturing of crankshaft
b) Manufacturing of engine cylinder
c) Manufacturing of boilers, pressure vessels
d) all of the above
N
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Shekapure

167. MCQ:
70. The most widely used type of welding is
a) Gas welding
b) Electric arc welding
c) Electric resistance welding
d) A and B
N
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Shekapure