5. Functional Classification of
Materials
Aerospace
Biomedical
Electronic Materials
Energy Technology and Environmental
Technology
Magnetic Materials
Photonic or Optical Materials
Smart Materials
Structural Materials
6.
7. Classification of Materials-Based on
Structure
Crystalline material is a material comprised of one or
many crystals. In each crystal, atoms or ions show a long-
range periodic arrangement.
Single crystal is a crystalline material that is made of
only one crystal (there are no grain boundaries).
Grains are the crystals in a polycrystalline material.
Polycrystalline material is a material comprised of
many crystals (as opposed to a single-crystal material that
has only one crystal).
Grain boundaries are regions between grains of a
polycrystalline material.
8. Classification of following factors
to make it suitable to the
appropriate functioning or end use
of the component
Temperature
Corrosion
Fatigue
Strain Rate
Environmental and Other Effects
11. Properties of materials
Mechanical properties of materials
Strength, Toughness, Hardness, Ductility,
Elasticity, Fatigue and Creep
Chemical properties
Oxidation, Corrosion, Flammability, Toxicity, …
Physical properties
Density, Specific heat, Melting and boiling point,
Thermal expansion and conductivity,
Electrical and magnetic properties
12. Material Specification
Chemical composition
Mechanical properties – Strength, hardness (under
various conditions: temperature, humidity, pressure)
Physical properties – density, optical, electrical,
magnetic
Environmental – green, recycling
13. Metals
Ferrous Metals
Cast irons
Steels
Super alloys
Iron-based
Nickel-based
Cobalt-based
Non-ferrous metals
Aluminum and its alloys
Copper and its alloys
Magnesium and its alloys
Nickel and its alloys
Titanium and its alloys
Zinc and its alloys
Lead & Tin
Refractory metals
Precious metals
14. General Properties and Applications of
Ferrous Alloys
• Ferrous alloys are useful metals in terms
of mechanical, physical and chemical
properties.
• Alloys contain iron as their base metal.
• Carbon steels are least expensive of all
metals while stainless steels is costly.
15. Carbon and alloy steels
Carbon steels
• Classified as low, medium and high:
1. Low-carbon steel or mild steel, <
0.3%C, bolts, nuts and sheet plates.
2. Medium-carbon steel, 0.3% ~ 0.6%C,
machinery, automotive and agricultural
equipment.
3. High-carbon steel, > 0.60% C, springs,
cutlery, cable.
16. Carbon and alloy steels
Alloy steels
• Steels containing significant amounts of
alloying elements.
• Structural-grade alloy steels used for
construction industries due to high
strength.
• Other alloy steels are used for its strength,
hardness, resistance to creep and fatigue,
and toughness.
• It may heat treated to obtain the desired
properties.
17. Carbon and alloy steels
High-strength low-alloy steels
• Improved strength-to-weight ratio.
• Used in automobile bodies to reduce
weight and in agricultural equipment.
• Some examples are:
1. Dual-phase steels
2. Micro alloyed steels
3. Nano-alloyed steels
18. Stainless steels
• Characterized by their corrosion
resistance, high strength and ductility, and
high chromium content.
• Stainless as a film of chromium oxide
protects the metal from corrosion.
22. AISI Designation for High-Strength Sheet
Steel
TABLE 5.3
Yield Strength Chemical
Composition
Deoxidation
Practice
psi x 10
3
MPa
35
40
45
50
60
70
80
100
120
140
240
275
310
350
415
485
550
690
830
970
S = structural alloy
X= lowalloy
W= weathering
D= dual phase
F = killed plus sulfide inclusion control
K= killed
O= nonkilled
23. Room-Temperature Mechanical Properties and
Applications of Annealed Stainless Steels
TABLE 5.4 Room-Temperature Mechanical Properties and Typical Applications of Selected Annealed
Stainless Steels
AISI
(UNS)
Ultimate
tensile
strength
(MPa)
Yield
strength
(MPa)
Elongation
in 50 mm
(%) Characteristics and typical applications
303
(S30300)
550–620 240–260 53–50 Screw machine products, shafts, valves, bolts,
bushings, and nuts; aircraft fittings; bolts; nuts;
rivets; screws; studs.
304
(S30400)
565–620 240–290 60–55 Chemical and food processing equipment,
brewing equipment, cryogenic vessels, gutters,
downspouts, and flashings.
316
(S31600)
550–590 210–290 60–55 High corrosion resistance and high creep strength.
Chemical and pulp handling equipment,
photographic equipment, brandy vats, fertilizer
parts, ketchup cooking kettles, and yeast tubs.
410
(S41000)
480–520 240–310 35–25 Machine parts, pump shafts, bolts, bushings, coal
chutes, cutlery, tackle, hardware, jet engine parts,
mining machinery, rifle barrels, screws, and
valves.
416
(S41600)
480–520 275 30–20 Aircraft fittings, bolts, nuts, fire extinguisher
inserts, rivets, and screws.
24. Tool and die steels
• Designed for high strength, impact
toughness, and wear resistance at a range
of temperatures.
25. Basic Types of Tool and Die
Steels
TABLE 5.5
Type AISI
High speed
Hot work
Cold work
Shock resisting
Mold steels
Special purpose
Water hardening
M (molybdenum base)
T (tungsten base)
H1 to H19 (chromium base)
H20 to H39 (tungsten base)
H40 to H59 (molybdenum base)
D (high carbon, high chromium)
A (medium alloy, air hardening)
O (oil hardening)
S
P1 to P19 (low carbon)
P20 to P39 (others)
L (low alloy)
F (carbon-tungsten)
W
26. Processing and Service Characteristics of
Common Tool and Die Steels
TABLE 5.6 Processing and Service Characteristics of Common Tool and Die Steels
AISI
designation
Resistance to
decarburization
Resistance to
cracking
Approximate
hardness
(HRC) Machinability Toughness
Resistance to
softening
Resistance to
wear
M2 Medium Medium 60–65 Medium Low Very high Very high
T1 High High 60–65 Medium Low Very high Very high
T5 Low Medium 60–65 Medium Low Highest Very high
H11, 12, 13 Medium Highest 38–55 Medium to high Very high High Medium
A2 Medium Highest 57–62 Medium Medium High High
A9 Medium Highest 35–56 Medium High High Medium to
high
D2 Medium Highest 54–61 Low Low High High to very
high
D3 Medium High 54–61 Low Low High Very high
H21 Medium High 36–54 Medium High High Medium to
high
H26 Medium High 43–58 Medium Medium Very high High
P20 High High 28–37 Medium to high High Low Low to
medium
P21 High Highest 30–40 Medium Medium Medium Medium
W1, W2 Highest Medium 50–64 Highest High Low Low to
medium
Source: Adapted from Tool Steels, American Iron and Steel Institute, 1978.
