Post on 27-Oct-2014
description
Selection Of Materialfor
CONNECTING ROD
The connecting rod does this important task of converting reciprocating motion of the piston into rotary motion of the crankshaft. It consists of an upper section which is joined to the piston with the help of a gudgeon pin and a lower section which gets attached to the crank shaft with bolts.
IntroductionIntroduction
An Example of a Connecting Rod
Stresses are induced in a connecting rod due to the axial forces action on it. These forces arise from gas pressure and inertia of piston.
The maximum axial load is compressive (at TDC).
Bending stresses also occur after firing due to a certain angle of inclination of the rod.
Stresses
After understanding the stresses developed in a connecting rod, we can enlist the following material requirements:-
1. High strength in both tension and compression.
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.
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 it’s properties at higher temperatures which can be developed during engine operation.
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 it’s properties at higher temperatures which can be developed during engine operation.
4. High impact strength.
Based on these requirements, the following materials can be selected:-
• Cast Iron
• Medium Carbon Steel ( 45 S 6 )
• Aluminum
• Titanium
The following influencing factors have to be considered:-
1.Cost
The following influencing factors have to be considered:-
1.Cost
2.Durability
The following influencing factors have to be considered:-
1.Cost
2.Durability
3.Weight
The following influencing factors have to be considered:-
1.Cost
2.Durability
3.Weight
4.Ease of Manufacture / Machinability
The following influencing factors have to be considered:-
1.Cost
2.Durability
3.Weight
4.Ease of Manufacture / Machinability
5.Availability
0
10
20
30
40
5060
70
80
90
CastIron
Al. M.C.S Ti
Cost
0102030405060708090
CastIron
Al. M.C.S Ti.
Durability
0
10
20
30
40
50
60
70
80
90
CastIron
Al. M.C.S Ti.
Weight
0
10
20
30
40
50
60
70
80
CastIron
Al. M.C.S Ti.
Availability
0
10
20
30
40
50
60
70
80
Castiron
Al. M.C.S Ti.
E.O.M
0
10
20
30
40
50
60
70
80
90
C.I Al. M.C.S Ti.
CostDbt.WeightAvail.Mach.
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 and light-weight dominate over the cost factor.