1. SUBJECT:
LEARNING OUTCOMES:
Upon completion of the course, student will be able to
demonstrate the knowledge and understanding of:
• Properties and uses
• Process
• Basic metallurgy, metals and processes
• Non-metallic materials
• Materials under load
• Vibration

2. ASSESSMENT:
Progress Tests 1 15%
Progress Tests 2 15%
Assignments 10%
Final Examination 60%

3. • Explains in simple terms what influences the choice of material for a
marine engineering component
• Describes in simple terms what is meant by the following mechanical
properties: elasticity, brittleness, hardness, strength, toughness,
ductility, malleability, plasticity and machinability
• Explains what is meant by low-; medium- and high-carbon steels
• Compares the tensile strength, ductibility, and hardness of low-;
medium- and high carbon steels
• States the uses of low-; medium- and high carbon steels
• Describes the properties of cast iron and gives examples of its uses
• Defines an alloy
• States the uses of aluminum, copper, zinc, lead, tin, and antimony
• States the component metals of brass, bronze and white metal
• States the uses of the above alloys
• Explains why the above alloys are suitable for the uses of the above
objectives

4. Types of Materials

6. Physical
Chemical
Mechanical
Properties of a metal
Electrical
Technological
Thermal

7. Mechanical Properties of a Metal
• Elasticity defined as the property of a metal by virtue of which it is
able to retain its original shape and size after removal of the load.

8. 2. Brittleness defined as the property of a metal by virtue of which it
will fracture without any appreciable deformation.
3. Hardness defined as the property of a metal by virtue of which it is
able to resist abrasion, indentation and scratching by harder bodies.

9. 4. Strength defined as the property of a metal by virtue of which it
can withstand an external force or load without rupture.
Types of strengths: elastic, plastic, tensile, compressive, shear,
bending and torsion

10. 5. Toughness defined as the property of a metal by virtue of which it
can absorb maximum energy before fracture takes place.

11. 6. Ductility defined as the property of a metal by virtue of which it
can be drawn into wires or elongated before rupture takes place.

12. 7. Malleability defined as the property of a metal by virtue of which it
can be deformed into thin sheets by rolling or hammering without
rupture.
The following common metals have malleability in the decreasing
order:
Gold, silver, aluminum, copper, tin, platinum, lead, zinc, iron and
nickel

13. 8. Plasticity defined as the property of a metal by virtue of which
a permanent deformation take place whenever it is subjected to
the action of external forces.

14. 8. Plasticity defined as the property of a metal by virtue of which
a permanent deformation take place whenever it is subjected to
the action of external forces.
9. Machinability defined as the property of a metal by virtue of
which indicates the case with which it can be cut or removed
by cutting tools in various machining operations such as
turning, drilling, boring, milling etc.

15. A vast range of metals exist and they fit in two categories,
‘ferrous’ and ‘non-ferrous’ metals. These metals can be used to
build/manufacture an equally large range of items.
FERROUS METALS - Metals that contain iron
NON-FERROUS METALS - Metals that do not contain iron

16. SOME FERROUS METALS AND PROPERTIES
NAME ALLOY OF PROPERTIES USES
Mild Steel Carbon 0.1 - 0.3% Tough. High tensile strength. Can Most common
Iron 99.9 - 99.7% be case hardened. Rusts very metal used in
easily. school
workshops. Used
in general metal
products and
engineering.
Carbon Steel Carbon 0.6 - 1.4% Tough. Can be hardened and Cutting tools
Iron 99.4 - 98.6% tempered. such as drills.
Stainless steel Iron, nickel and Tough, resistant to rust and stains. Cutlery, medical
chromium. instruments.
Cast iron Carbon 2 - 6% Strong but brittle. Compressive Castings,
Iron 98 - 94% strength very high. manhole covers,
engines.
Wrought iron Almost 100% iron Fibrous, tough, ductile, resistant Ornamental gates
to rusting. and railings. Not
in much use
today

17. SOME NON - FERROUS METALS AND PROPERTIES
NAME COLOUR ALLOY OF; PROPERTIES USES
Aluminu Light grey Aluminum 95% Ductile, soft, malleable, Window frames,
m Copper 4% machines well. Very aircraft, kitchen
Manganese 1% light. ware.
Copper Reddish Not an alloy Ductile, can be beaten Electrical
brown into shape. Conducts wiring, tubing,
electricity and heat. kettles, bowls,
pipes.
Brass Yellow Mixture of copper Hard. Casts and machines Parts for
and zinc 65% - 35% well. Surface tarnishes. electrical
most common ratio. Conducts electricity. fittings,
ornaments.
Silver Whitish grey Mainly silver but Ductile, Malleable, Jewellery,
alloyed with copper solders, resists corrosion. solder,
to give sterling silver. ornaments.
Lead Bluish grey Not an alloy. Soft, heavy, ductile, loses Solders, pipes,
its shape under pressure. batteries,
roofing.

18. If you use metals as part of a practical project a knowledge of the
shape or ‘section’ of lengths of metals is important. The diagrams
below show examples of solid lengths and also tubes. When you order
metals you need to describe the section you want.
SECTIONS - SOLIDS AND TUBES
ROUND SECTION SQUARE SECTION
HEXAGONAL SECTION L-SECTION

19. ROUND TUBE SQUARE TUBE
HEXAGONAL TUBE L-SECTION TUBE

20. The American Iron and Steel Institute (AISI) defines carbon
steel as follows:
Steel is considered to be carbon steel when no minimum content is
specified or required for chromium, cobalt, columbium [niobium],
molybdenum, nickel, titanium, tungsten, vanadium or zirconium,
or any other element to be added to obtain a desired alloying
effect;
Classification:
• Low-carbon steel, also known as mild steel. It as less
than 0.30 percent carbon and generally used for industrial
products: bolts, nuts, sheet, plate, tubes and machine
components.

21. • Medium-carbon steel has 0.30 percent to 0.60 percent carbon. It is
generally used in application requiring higher strength such as
machinery, automotive and agricultural equipment parts, rail road
equipment and parts for metalworking machinery.
3. High-carbon steel has more than 0.60 percent carbon. It is generally
used for parts requring strength, hardness and wear resistance such as
cutting tools, cable, springs and cutlery.

22. Iron is one of the three magnetic elements. Cast iron is very brittle
but it has a greater resistance to corrosion than either pure iron or
steel. Cast iron is used for manhole covers on roads and pavements
and as engine blocks for petrol and diesel engines.
Iron from the blast furnace
contains about 5% carbon
which comes from the coke
in the furnace.
It is cast into moulds called
pigs and the iron is called
cast iron or pig iron.

23. An alloy is a solid solution or homogeneous mixture of two or more
elements, at least one of which is a metal, which itself has metallic
properties. It usually has different properties from those of its
component elements.
Alloys are used because they have specific properties or production
characteristics that are more attractive than those of the pure,
elemental metals. For example:
• some alloys possess high strength
• others have low melting points
• others are refractory with high melting temperatures
• some are especially resistant to corrosion
• and others have desirable magnetic, thermal, or electrical properties
These characteristics arise from both the internal and the electronic
structure of the alloy. An alloy is usually harder than a pure metal
and may have a much lower conductivity.

24. Aluminium is a silvery white and ductile member of the boron group
of chemical elements. It has the symbol Al.
Aluminium is the most abundant metal and too reactive chemically to
occur in nature as the free metal. Instead, it is found combined in over
270 different minerals. The chief source of aluminium is bauxite ore.
Aluminium is remarkable for its ability to resist corrosion and its low
density. Structural components made from aluminium and its alloys
are vital to the aerospace industry and very important in other areas of
transportation and building.
Aluminium is the most widely used non-ferrous metal. Relatively
pure aluminium is encountered only when corrosion resistance and/or
workability is more important than strength or hardness.

25. A thin layer of aluminium can be deposited onto a flat surface by
physical vapor deposition. When so deposited, a fresh, pure
aluminium film serves as a good reflector (approximately 92%) of
visible light and an excellent reflector (as much as 98%) of medium
and far infrared.
Pure aluminium has a low tensile strength, but when combined with
thermo-mechanical processing, aluminium alloys display a marked
improvement in mechanical properties, especially when tempered.
Aluminium alloys form vital components of aircraft and rockets as a
result of their high strength-to-weight ratio.
Aluminium readily forms alloys with many elements such as copper,
zinc, magnesium, manganese and silicon.

26. Copper is a chemical element with the symbol Cu. It is a ductile
metal with excellent electrical conductivity and is rather supple in
its pure state and has a pinkish luster which is unusual for metals
which are normally silvery white. It finds use as a heat conductor,
an electrical conductor, as a building material, and as a constituent
of various metal alloys.
Copper is also an important ingredient of many useful alloys—
combinations of metals, melted together.
Brass is copper plus zinc. If it contains mostly copper, it is a
golden yellow color; if it is mostly zinc, it is pale yellow or silvery.
Brass is one of the most useful of all alloys; it can be cast or machined
into everything from candle sticks to cheap, gold-imitating jewelry that
turns your skin green.
Bronze is mainly copper plus tin

27. Uses of Copper
Copper is vital for computers to work. Copper is used in building the
integrated circuits, chips, and the printed circuit boards of the computer
alone. Copper is becoming more and more popular to use in the layers
of the build-up of a chip. IBM announced a plan to use copper in its
computer chip rather than aluminum. Doing so would make the
computer to be cheaper and would allow it to make faster calculations.
Copper is often used as a conductor of electricity. Almost all electrical
devices rely on copper wiring because copper is inexpensive and
highly conductive. The conductivity of copper is second only to silver.
The reason why copper is a good conductor is because there are a lot
of free electrons that can carry the flowing current efficiently. These
free electrons do not remain permanently associated with the copper
atoms, instead they form an electron ‘cloud’ around the outside of the
atom and are free to move through the solid quickly.

28. Copper is often used in currency. From 1909 to 1982, the American
penny was 95% copper. The other 5% was either zinc or bronze
depending on the year. The only exception was 1943. That year the
penny had zinc-plated steel in it. Unfortunately, the steel was magnetic
and kept getting stuck in vending machines. Also, the zinc corroded
easily and was therefore often mistaken for a dime. In the early 1980’s
copper increased in value. So in 1982, the United States switched the
penny’s core to zinc and coated it with copper.

29. Zinc is a metallic chemical element with the symbol Zn. Commercially
pure zinc is known as Special High Grade, often abbreviated SHG, and
is 99.995% pure.
Zinc is relatively non-reactive in air or water. Consequently, it is
applied in thin layers to iron and steel products that need to be
protected from rusting. This process is called galvanizing in which the
metal is dipped in molten zinc.
The second largest use of zinc is as an alloy and the remaining zinc
consumption is for making paint, chemicals, agricultural applications,
in the rubber industry, in TV screens, fluorescent lights and for dry cell
batteries.
Zinc is also used as a main alloy for Brass.

30. (Option)
One of the biggest uses of zinc is in making protective coatings for
steel. The development of the wide range of zinc coatings arose from
two happy accidents of chemistry, the relatively slow and predictable
rate of atmospheric corrosion of zinc compared with steel, and the
relative positions of zinc and iron in the electrochemical series. Zinc
will corrode preferentially to give cathodic protection to iron when
both are in contact in an aqueous medium. This is used to good effect
to protect immersed structures such as ships’ hulls, drilling rigs and
pipelines. It also means that any bare areas in a zinc coating on steel,
caused by damage or operations such as cutting or drilling, are still
protected by the surrounding zinc.
Taken together, these two factors provide the basis of a unique
corrosion protection system which uses some 4 million tonnes of zinc
annually to protect around 100 million tonnes of steel. This represents
almost half the total world consumption of zinc.

31. Tin is a chemical element with the symbol Sn. This silvery, malleable
poor metal that is not easily oxidized in air and resists corrosion, is
found in many alloys and is used to coat other metals to prevent
corrosion.
Tin is obtained chiefly from the mineral cassiterite, where it occurs as
an oxide. It can be alloyed with copper to make bronze. Pewter alloys
contain from 85% up to 99% tin.
Lead is a main group element with a symbol Pb. Lead is a soft,
malleable poor metal, also considered to be one of the heavy metals.
Lead has a bluish white color when freshly cut, but tarnishes to a dull
grayish color when it is exposed to air and is a shiny chrome silver
when melted into a liquid.
Lead is used in building construction, lead-acid batteries, bullets and
shot, weights, and is part of solder, pewter, and fusible alloys.

32. Antimony is a chemical element with the symbol Sb. A metalloid,
antimony has four allotropic forms. The stable form of antimony is a
blue-white metalloid. Yellow and black antimony are unstable non-
metals.
Antimony is used in flame-proofing, paints, ceramics, enamels, a wide
variety of alloys, electronics, and rubber.
Brass is a metal alloy of Copper and Zinc, with copper content
ranging from 58% to 95%. In addition to Zinc, the major alloying
element, small additions (less than 5%) of other alloying elements are
added to modify the properties so that the resulting material is fit for a
given purpose. Typical applications: are nuts, bolts, screw threads.

33. Important Properties of Brass:
• Excellent machinability
• Good strength (250 – 500 MPa)
• Corrosion resistance
• Conductivity
• Non sparking
• Attractive color
• Wear resistance
• Readily recycled
• Toughness
• No loss of properties at temperature up to 200OC

34. Bronze is any of a broad range of copper alloys, usually with tin as the
main additive, but sometimes with other elements such as phosphorus,
manganese, aluminum, or silicon.
The tin in bronze makes it more resistant to wear than unalloyed
copper. Bronzes today are usually stronger and more resistant to
corrosion than brass.
The variations in bronze composition significantly affect its
characteristics: Wearability, machinability, corrosion-resistance and
ductility for deep drawing are often considered.
Bronze parts are typically used for bearings, clips, electrical
connectors and springs.

35. Commercial bronze, is 90-10, or 90% copper/10% tin. It is frequently
the least expensive, most easily obtained grade of bronze.
Aluminium bronze is a copper-aluminium alloy that may contain iron,
nickel, and/or silicon for greater strength. It is used for tools and,
because it will not spark when struck, for parts to be used around
flammable materials. Aluminium bronze is frequently used for aircraft
and automobile engine parts.
Manganese bronze is actually a brass containing manganese. It is often
used for ship propellers because it is strong and resists saltwater
corrosion.

36. The white metals are any of several light-colored alloys used as a
base for plated silverware, ornaments or novelties, as well as any
of several lead-base or tin-base alloys used for things like bearings,
jewellery, miniature figures, fusible plugs, some medals and metal
type.
Some of the metals that make up a white metal alloy are antimony,
tin, lead, cadmium, bismuth, and zinc. Not all of these metals are
found in all white metal alloys but are mixed to achieve a desired
goal or need.
As an example, a base metal for jewelry needs to be castable
, polishable, have good flow characteristics, have the ability to cast
fine detail without an excessive amount of porosity and cast at
between 230 °C and 300 °C