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7/28/2019 Conrod Ppt Nf 2
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Selection Of Material
for
CONNECTING ROD
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The connecting rod does this important taskof converting reciprocating motion of thepiston into rotary motion of the crankshaft. It
consists of an upper section which is joinedto the piston with the help of a gudgeon pinand a lower section which gets attached tothe crank shaft with bolts.
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An Example of a Connecting Rod
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Stresses are induced in a connecting roddue to the axial forces action on it. Theseforces arise from gas pressure and inertiaof piston.
The maximum axial load is compressive (at TDC).
Bending stresses also occur after firing due to acertain angle of inclination of the rod.
Stresses
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After understanding the stresses developed in a
connecting rod, we can enlist the following
material requirements:-
1. High strength in both tension and
compression.
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After understanding the stresses developed in a
connecting rod, we can enlist the following
material requirements:-
1. High strength in both tension and
compression.
2. High fatigue strength.
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After understanding the stresses developed in a
connecting rod, we can enlist the following
material requirements:-
1. High strength in both tension and
compression.
2. High fatigue strength.3. It must retain its its properties at higher
temperatures which can be developed during
engine operation.
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After understanding the stresses developed in a
connecting rod, we can enlist the following
material requirements:-
1. High strength in both tension and
compression.
2. High fatigue strength.3. It must retain its its properties at higher
temperatures which can be developed during
engine operation.
4. High impact strength.
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Based on these requirements, the
following materials can be selected:-
Cast Iron
Medium Carbon Steel ( 45 S 6 )
Aluminum
Titanium
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The following influencing factors have to
be considered:-
1.Cost
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The following influencing factors have to
be considered:-
1.Cost
2.Durability
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The following influencing factors have to
be considered:-
1.Cost
2.Durability
3.Weight
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The following influencing factors have to
be considered:-
1.Cost
2.Durability
3.Weight
4.Ease of Manufacture / Machinability
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The following influencing factors have to
be considered:-
1.Cost
2.Durability
3.Weight
4.Ease of Manufacture / Machinability
5.Availability
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0102030405060708090
CastIron Al. M.C.S Ti
Cost
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0102030405060708090
CastIron
Al. M.C.S Ti.
Durability
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0102030405060708090
CastIron
Al. M.C.S Ti.
Weight
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01020304050607080
CastIron Al. M.C.S Ti.
Availability
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01020304050607080
Castiron Al. M.C.S Ti.
E.O.M
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0102030405060708090
C.I Al. M.C.S Ti.
CostDbt.WeightAvail.Mach.
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Result:-
In accordance with these design steps,
Medium Carbon Steel is preferred as a
material for connecting rod. A commonly
used form of MCS is 45 S 6.
Aluminum and titanium can be used for high
performance engines like F1 cars where strength andlight-weight dominate over the cost factor.