The document discusses the process of powder metallurgy which involves 6 main steps: 1) powder production through atomization or other methods, 2) blending powders, 3) compaction into shapes, 4) sintering using solid or liquid phase processes, 5) finishing like sizing, and 6) testing. Key advantages are close dimensional control, low scrap rates, and ability to make net-shape parts reducing machining. Applications include automotive components, cutting tools, and fuel for rockets.

1. POWDER
METALLURGY
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2. POWDER METALLURGY
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3. 1. POWDER PRODUCTION
2. BLENDING OR MIXING
3. COMPACTION
4. SINTERING
5. FINISHING(SIZING OR IMPREGNATION)
6. TESTING OR INSPECTION
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4. PowderMetallurgy-AdityaDeshpande
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5. PowderMetallurgy-AdityaDeshpande
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6.  Atomization the most
common
 Others
 Chemical reduction of
oxides
 Electrolytic deposition
 Different shapes
produced
 Will affect compaction
process significantly
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7. •This method involves mainly milling action in which ball mills, eddy
mills, roll crusher mills are used.
•In ball milling method material to be disintegrated is tumbled together
with
a large number of hard wear resistant solid balls which by hitting the
material, cause to break it down to fine particles
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8. Atomization consist of mechanically
disintegrating a stream of molten metal
into fine particles by means of a jet of
compressed air, inert gas or water, the
powder so formed being collected in
dust collector
Water and gas Atomising
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9.  Used to production of copper powders used in oil less bronze
bearings
 Electrolysis copper sulphate solution in which copper anode and
aluminum cathode used.
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10.  MIXING: mixing is used to
produce uniform distribution
of powder.
 BLENDING : Blending is an
operation of through mixing
of powder with different
composition
Double cone mixer
Y shape mixer
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11.  Can use master alloys, (most commonly) or
elemental powders that are used to build up the
alloys
 Master alloys are with the normal alloy ingredients
 Elemental or pre-alloyed metal powders are first
mixed with lubricants or other alloy additions to
produce a homogeneous mixture of ingredients
 The initial mixing may be done by either the metal
powder producer or the P/M parts manufacturer
 When the particles are blended:
 Desire to produce a homogenous blend
 Over-mixing will work-harden the particles and produce
variability in the sintering process
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12. Various
blenders
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13.  During compacting the volume of the powder is reduced and voids
are reduced
 When clean metallic particles are pressed together cold welding
occurs. The compact generally has 70% of its density at this stage.
 Compacting can be done to different shapes such as circular,
square,hollow circular
 Compacting pressures of some metal powders:
METAL POWDER PRESSURE(Mpa)
Al 75-275
Al2O3 100-150
BRASS 400-700
W 75-150
Fe 400-800
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14.  Usually gravity filled
cavity at room
temperature
 Pressed at 60-100 ksi
 Produces a “Green”
compact
 Size and shape of finished
part (almost)
 Not as strong as finished
part – handling concern
 Friction between
particles is a major
factor
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15. FIG : Press for PM
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16. PowderMetallurgy-AdityaDeshpande
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17.  Bonding common surfaces of adjacent particles touching each others
in a mass of powder or compact by heating is called sintering
 Sintering is usually carried out in electric resistance furnace , gas or
oil fired furnace.
 Types of sintering:
A. Solid phase sintering
B. Liquid phase sintering
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18.  Parts are heated to ~80%
of melting temperature
 Transforms compacted
mechanical bonds to
much stronger metal
bonds
 Many parts are done at
this stage. Some will
require additional
processing
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19. SOLID PHASE SINTERING
In this process the reen compacts are
heated usually above recrystallization
temperature of low melting metal
LIQUID PHASE SINTERING
The liquid phase sintering is carried out above the melting point
of one of the alloy constituting or above meltin point of alloy
formed during sintering
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20.  the sintered component have slightly different size from the desired
size due to sintering distortion this can be correct by sizing
operation.
 This is done by placing component in master dye and applying
pressure on it
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21.  This term is used when oil or other fluid is permitted in the pores of
sintered materials
 Application : oil impregnated bearings, gears and similar
components
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22.  An operation in which the pores of PM part filled with molten
metals . The melting point of filler material is below that of PM part.
 It gives:
 Improved strength
 Improved toughness
 Less porosity
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23. 1. Controlled porosity for self lubrication or filtration
uses
2. Can be very economical at large run sizes (100,000
parts)
3. Close control over the dimensions
4. So no or minimum machining after process. So
scrap – minimum(yield up to 99%)
5. No necessity of skilled person
6. Production of components of any desired
composition
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24. 1. Controlled porosity can be obtained.
2. P/M parts can be welded, machined, heat treated.
3. Production of refractory material is possible without
melting.
4. Production of components of metal which are
completely insoluble in liquid state(layer type
systems)
5. Mfg- cemented carbide cutting tool only by P/M.
6. Components of properties similar to parent metal can
be produced.
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25. 1. Problem of the material powder handling.
2. Limitation of size of components.
3. High initial cost so not suitable for small production.
4. Parts having poor corrosion resistance due to
porosity.
5. As stated above- hardness, ductility, toughness,
strength are poor as compared to conventional
manufacturing.
6. Components with theoretical density are not
manufactured.
7. Specialty machines
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26. 1. Automotive field
2. Defence field
3. High temperature applications
4. Aerospace field
5. Atomic energy field
6. others
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32. Self lubricating bearings
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34. Carbide tips for cutting tools
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35. a) Tungsten filaments in
electric bulb
b) Filament in X- ray tubeFig. a)
Fig. b)
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36. Solid
fuel in
rockets,
space
launch
vehicles
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37. Bullets and
cartridge cases
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