1. DESIGN FUNDAMENTALS
Prof. kiran gore

2. Need of design Functional requirement User comfort Safety Modification
Appearance
Cost reduction

3. General consideration in design
Type of load
Selection material
shape & size
Friction & lubrication
Operational safety
Machine availability
Use of standard parts

4. General consideration in design
Production quantity
Maintenance of element
Life of element
Capacity of element
Weight of element
Cost of element

5. steps in design Define the need Synthesis (mechanism) Analysis
Selection of material
Design of elements (size, shape)
Modification
Detailed drawing
Production

6. Properties of material
Elasticity
Plasticity
Toughness
Resilience
Stiffness
Ductility
Brittleness
Strength
fatigue
Hardness

7. 1. Elasticity
To regains its original shape after deformation When the external applied force is removed.

8. 2. Plasticity
not regains its original shape after deformation When the external applied force is removed.

9. 3. Toughness
Capacity of material to absorb the energy before failure.

10. Resilience
Total amount of energy absorbed by material during its elastic deformation.

11. 4. Stiffness
Ability of material to resist deformation under stress.

12. 5. Ductility
The ability of material to undergo plastic deformation under tensile loading.

13. 6. Brittleness
It is the property of breaking of a material with little permanent deformation.

14. 7. Strength
Ability of material to resist the externally applied force without failure.

15. 8. Fatigue
Ability of a material to resist deformation without failure when subjected to fatigue load.

16. 9. Hardness
It is the property of a material which enables it to resist penetration, abrasion, plastic deformation is called as hardness.

17. Classification of engineering materials
Metals & their Alloys
1. Ferrous metals
2. Non-ferrous metals
Non-metals
1.Rubber
2.Plastics
3.Wood
4.Glass

18. 3.Steel(Plain carbon steel)
Ferrous metals
Are those which contains iron as their main element or constituent.
1. Ferrous metals
1.Cast Iron
2. Alloy Cast Iron
3.Steel(Plain carbon steel)
4.Alloy steel

19. 1.Cast Iron Melting point is low 1140 to 1240 ⁰ C
Cast iron are formed by melting metal and casting hence called as cast iron.
Alloy of four element
Iron
Carbon ( 2.3 to 3.7%)
Silicon
Manganese .
sometime additional alloying element are added.
Melting point is low 1140 to 1240 ⁰ C

20. Properties of cast iron
High carbon content makes molten iron very fluid, so that it can be poured into intricate shape.
The presence of graphite in the metal provides excellent machinability, wear resistance & ability to damp vibration.
Excellent castability because of high fluidity

21. Advantages Low cost material High compressive strength
Good damping capacity.
High resistance to wear and abrasion.
High hardness
Corrosion resistance is fairly good
Excellent machinability

22. Limitations It is brittle in nature.
Its mechanical properties like toughness, stiffness, resilience poor.
due to brittleness, it is poor against fatigue and impact loading.

23. Applications of cast iron
cast iron are used in the following machine elements:
Machine beds, columns, hammers, road-rollers.
Pipe fittings, valves, farm equipments, automotive parts.
camshafts, crank shafts, gears, pulleys , coupling
Motor covers, pump bodies, furnace parts.
Engine frames, piston and cylinder, cylinder blocks and bearing blocks, etc.

24. 2. Alloy Cast Iron Generally, cast iron has - low impact resistance,
- corrosion resistance and
-temperature resistance.
nickel, chromium, copper, silicon, vanadium, molybdenum etc. are used for this purpose.

25. Alloying element Chromium Nickel toughness, ductility, & strength
Hardness,
harden ability,
wear resistance,
Corrosion resistance
Nickel
toughness,
ductility, &
strength

26. Alloying element Silicon Vanadium hardness, toughness &
Deoxidizing agent
Improve elastic limit & resilience
Vanadium
hardness,
toughness &
fatigue strength

27. Alloying element Molybdenum- hardness, toughness,
high temperature strength
Tungsten-
hardness
toughens
It maintains hardness even at red heat

28. Properties of alloy cast iron
It has high strength.
It has high oxidation resistance.
It has high wear resistance and corrosion resistance.

29. Applications of cast iron
Gears, automobile parts like pistons, piston rings, camshaft, crank shaft, cylinders.
Brake drum, pulleys, grinding machinery parts, etc.

30. 3.Plain Carbon Steels _ plain carbon steel is an alloy of iron &
carbon ( less than 1.7%)
With
Manganese ( less than 1.5% )
Silicon ( less than 0.5% )
Sulphur
Phosphors

31. The plain carbon steel with less than
0.3% carbon – low carbon steel or MS.
0.3 % to 0.6% - medium carbon steel.
More than 0.6% - high carbon steel
Carbon content increases the strength & hardness of steel.

32. Properties of Plain Carbon Steel
They are ductile in nature.
They have high fatigue and impact strength.
Their mechanical properties like toughness, stiffness, resilience, etc. are high.

33. Advantages They have high tensile strength.
They have high resilience and toughness .
They can sustain fatigue and impact load.

34. Limitations The vibration damping property of steel is poor.
They cannot be cast into complicated shapes.
They have low wear resistance.
Its cost is more than cast iron.

35. Applications
Low carbon steels- automobile body, spindles, levers, light duty gears.
Medium carbon steel- nuts & bolts, transmission shaft, axles, gears, cylinders &connecting rod.
High carbon steel- coil spring, leaf spring, washers.

36. 4.Alloy Steel alloy steel is an alloy of iron & carbon that contain
manganese (more than 1.5%)than specified for plain carbon steel.
silicon (more than 0.5%) than specified for plain carbon steel.
other alloying element like – nickel, chromium, molybdenum, vanadium or tungsten

37. Properties of Alloy Steel
They are ductile in nature.
They have high corrosion resistance.
They have high strength.
They are soft and having high toughness.

38. Advantages They have high tensile and fatigue strength.
They have high wear resistance, corrosion resistance.
They have high toughness and resilience.

39. Limitations Alloy steel cannot be cast into complicated shapes.
Their vibration damping property is poor.
They are costlier than steel and cast iron.

40. Applications
Aircraft engine parts, heat exchangers, wrist watches, sanitary fittings.
Combustion chamber, furnace parts, gas burners, screws.
Valves, pumps, surgical instruments, razor blades, turbine blades, missiles, structural components, etc.

41. High alloy steel (stainless steel)
At leat12 % chromium are called stainless steel.
Properties- higher corrosion resistance,
Heat resisting property- nickel & molybdenum.
Used – high temperature chemical handling equipment, boiler shell, food processing equipment, springs

42. Advantages Non-Ferrous Metals
Non-ferrous metals are those which contain a metal other than iron as their main element or constituent.
Advantages
Low density, hence light in weight.
High electrical conductivity.
Easy to fabricate.
High corrosion resistance.

43. Non ferrous alloys
Copper & its alloys
Aluminum & its alloys

44. Copper and its Alloys Copper & its alloys a. Brass ( copper & zinc)
b. Bronze
( copper & tin)

45. Properties of Copper Applications Heat exchangers
high ductility.
high electrical and thermal conductivity.
non-magnetic in nature.
easily alloyed with other metals.
corrosion resistance is also high.
Applications
Electrical parts
Heat exchangers
Household utensils, etc.

46. a. Brass Brass is an alloy of ( copper + zinc + small
amount of other alloying elements )
Ex. Addition of lead improves its machinability.
Zing – 5 to 45%
The ductility of brass increases with increasing zing percentage.
Beyond 37%- fall in ductility.

47. Advantages Limitations high corrosion resistance. high ductility.
Low coefficient of friction.
It has high machinability.
Limitations
Low strength.
High cost.

48. Applications Coins, needles, jewellery, condenser tubes. springs.
• welding rods,
machine parts.
sliding contact bearing.

49. Advantages b. Bronze Bronze is an alloy of ( copper + tin )
With other alloying element like : silicon aluminum, beryllium etc.
Advantages
high corrosion resistance
low coefficient of friction,
Better strength than brass,
better wear resistance than brass,
Good machinability.

50. Limitations Applications
The cost of bronzes is higher than the brasses.
The strength of bronzes is lower than the ferrous metals..
Applications
Bronzes are used in the manufacturing of following parts :
Springs, gears, bearings, electrical appliances.
Bolts, rivets, pressure vessels, bells, marine containers.
Valve bodies, gun barrels, pipe fittings, etc.

51. Types of bronze Phosphor bronze it contain, It contain
copper %
tin – %
phosphorous- 0.1 – 0.3%
II. Tin bronze or gun metal
It contain
copper- 88%
tin – 10 %
zing- 2%
IV. Silicon bronze
it contain,
copper- 96%
silicon – 3%
manganese- 1%
III. Aluminum bronze
It contain
copper- 86%
aluminum – 9-10 %
iron- 4%

52. 2. Aluminium and its Alloys
Aluminum is another widely used non-ferrous metal.
Aluminum can be easily alloyed with elements like silicon, copper, nickel, manganese, titanium, magnesium, etc.
Advantages
high thermal and electrical conductivity.
high corrosion resistance.
high toughness.
high castability.

53. Applications The aluminum alloy are used as material for
I.C. engine cylinder block, cylinder head
Gear box casting,
Fan blades
Window & door frames
Stressed parts in aircraft
Ship building
Chain covers

54. Non metals
The commonly used non metals are
Rubber
Plastic
Wood
Glass

55. Rubber Elastic in nature
Non-conductors of electricity and low heat conductors
chemical and corrosive resistances are also high
ductile in nature

56. Types of rubber
Rubber
a. Natural rubber
b. Synthetic rubber

57. 1. Natural rubber Milky liquid obtained from trees
(Sulphur + row rubber ) & heated
harder, stronger, rigid materials.
Losses strength when heated

58. Synthetic rubber(SBR)
- styrene & butadiene

59. Applications Vehicle tires, gaskets, erasers, pipes, tubes.
Belt conveyors, adhesives, tapes, seals, gloves, aprons, floor tiles, etc.
Brake liners, containers, wires and cables, engine mountings, etc.

60. PLASTIC (polymers) Characteristics of plastic Low density
Corrosion resistance
Low coefficient of friction
Produced in different colors
good mouldability
More economical than metals

61. Types of polymers / plastic
a. Thermoplastic
b. Thermosetting

62. 1. Thermoplastic Application Soften when heated & harder when cooled.
Repeatedly moulded
Application
- Electrical insulation, toys, musical instrument, photographic films, bottle, gaskets, refrigerator parts, plastic lenses.

63. Thermosetting Application
Soft during first heating & become permanentaly hard when cooled.
Can not be remoulded
Application
- Radio & T.V. cabinet, camera parts, automobile parts .

64. Thank you