MATERIAL TECHNOLOGY
NQF LEVEL 3
QUESTION 1: METALS, NON-METALS,
METAL PROCESSING AND MATERIALS
TESTING
1.1 Indicate whether the
following statements are TRUE or FALSE. Choose the answer and write only
'true' or 'false' next to the question number
(1.1.1 - 1.1.6) in the ANSWER BOOK.
1.1.1
Young's modulus (E) is the modulus
of elasticity which indicates
the
elasticity of a material. (1)
1.1.2 Yield point (YP) is the point at which formation changes from
elastic
to plastic behaviour. (1)
1.1.3 Non-metals have many different uses, both in the construction
industry
and in everyday life. (1)
1.1.4 Polyester resin burns with a yellow smoking flame, giving off
sweet-smelling
fumes. (1)
1.1.5 Metals tend to form compounds with other metals. (1)
1.1.6 You can pull a ductile metal to make a wire only by heating
it. (1)
1.2 Complete the following
sentences by filling the missing word(s).
Write only the word(s) next to
the question number (1.2.1 - 1.2.8) in the ANSWER BOOK.
1.2.1
The ... is the extension of a
material per unit length, or is the
change
in length divided by the length. (1)
1.2.2
Comprehensive strength is the ability
of a material to withstand a
crushing
load without ... . (1)
1.2.3
... plastics bubble and begin to
decompose before they soften. (1)
1.2.4
Glass fibre in the form of cloth
is used for ... and for filtering dust
and
other solid particles from gases and liquids. (1)
1.2.5
Tools and die steels are
specially alloyed to produce metals that are
strong, tough and resistant to ... and tear. (1)
1.2.6
Toughness is the ability of a
metal to withstand ... . (1)
1.2.7
After the ... has been checked
for correctness, the steel is tapped into the ladle and
the ingot moulds are filled from the ladle. (1)
the ingot moulds are filled from the ladle. (1)
1.2.8
The cupola furnace is made from
steel plates and is lined with ... (1)
1.3 Various possible options are
provided as answers to the following questions.
Choose the answer and write only
the letter (A - D) next to the question number (1.3.1 - 1.3.8) in the ANSWER
BOOK.
1.3.1
Choose the correct temperature range
for heating steel for spherodising
annealing:
A
Between 595 °C and 700 °C
B Between 650 °C and 700 °C
C
Between 750 °C and 700 °C
D
Between 550 °C and 680 °C (1)
1.3.2 Which ONE of the following materials is used to make
vehicle bodies
such as cars
and trucks?
and trucks?
A
High carbon steel
B
Stainless steel
C
Mild steel
D
Cast steel (1)
1.3.3 Non-metals have the following physical characteristic:
A
Elasticity
B
Ductility
C
Malleability
D
Brittleness (1)
1.3.4 Polymers have a number of properties
that are very useful, such as ...
A
being easy to manufacture.
B being relatively expensive.
C
having a high density.
D
having a low density. (1)
1.3.5
Which test will you apply if you often
test the strength of brittle material?
A
Tensile test
B
Compression test
C
Bending test
D
Impact test (1)
1.3.6 If you apply safety precautions when you
are testing a work piece, you should
wear ...
A safety boots. B safety gloves. C
safety glasses. D
a leather apron.(1) [20]
QUESTION 2: METALS
2.1 Name ONE of the properties of cast iron. (1)
2.2 2.2.1
State the carbon percentage
required in steel to be classified as a high
carbon steel. (1)
carbon steel. (1)
2.2.2 State what general weakness
this high carbon content causes in the
steel. (1)
2.3 Name
ONE property of lead. (1)
2.4 What
metal is used to make aeroplanes and kitchenware? (1)
2.5 Which
grade of commercial quality brass is called naval brass? (1)
2.6 Where
is class 460/3 copper pipe used? (1)
2.7 Describe
how nickel is manufactured. (3)
2.8 What
does the number range 2XXX to 7XXX indicate in metallurgical terms? (1)
2.9 Explain
ONE of the uses of each of the following non-ferrous metals:
2.9.1 Lead (1)
2.9.1 Lead (1)
2.9.2
Aluminium (1)
2.10 What should be done to plain carbon steel if components
are to be manufactured that have
requirements that exceed the capabilities of normal steel? (2)
requirements that exceed the capabilities of normal steel? (2)
2.11 Which
elements are added to steel to improve its machinability? (1)
2.12 During a manufacturing operation the cutting tool is forced into the work piece
which revolves at high speed.
2.12 During a manufacturing operation the cutting tool is forced into the work piece
which revolves at high speed.
2.12.1 What negative effect does this
forcing of the tool have on the revolving
work piece? (1)
2.12.2 What is done to remove this negative effect? (1)
2.12.3 What additional benefit does your answer in QUESTION 2.12.2 have on the machining
process? (1)
2.12.2 What is done to remove this negative effect? (1)
2.12.3 What additional benefit does your answer in QUESTION 2.12.2 have on the machining
process? (1)
2.13 Name
ONE use of bronze. (1)
[20]
QUESTION 3: NON-METALS
3.1 Name
FOUR advantages and FOUR disadvantages of plastics. (8)
3.2 Name
FOUR characteristics of silicons. (4)
3.3 Name
FIVE examples of objects used in the industry which are made of PVC
(polyvinyl chloride). (5)
3.4 Describe,
by means of a sketch, thermosetting plastics that consist of a cross-linked
molecular chain with a regular structure. (1)
molecular chain with a regular structure. (1)
[20]
QUESTION 4: METAL PROCESSING
4.1 Name
TWO ingredients of the charge in a cupola furnace. (2)
4.2 Which
material is added to the molten metal in the arc furnace to remove the
carbon and remaining phosphorus
during stage 2? (1)
4.3 With
which material is the bottom of the arc furnace covered before the charge is added? (1)
4.4 Describe
the operation of a rotor furnace. (3)
4.5 List the
advantages and disadvantages of the following furnaces:
4.5.1 The Bessemer furnace (3)
4.5.1 The Bessemer furnace (3)
4.5.2
The arc furnace (3)
4.6 Does
normalising increase the strength and toughness of steel? Answer YES or NO. (1)
4.7 In
which liquid is hardened steel quenched immediately after heating it to the right
tempering temperature? (1)
tempering temperature? (1)
4.8 You must
temper a twist drill. Answer the
following questions:
4.8.1 To what tempering temperature must the front of the drill
with the
cutting
edge be heated? (1)
4.8.2
At the appearing of which
tempering colour must the front of the
drill
be quenched again? (1)
4.9 Describe
the box method of carburising. (3)
[20]
QUESTION 5
5.1 A carbon steel test piece, hardened and tempered, was
tested in a Brinell Hardnell tester
using a 10 mm diameter ball. The load
was 300 kg and the diameter of the
impression was measured to be 4,12 m.
Determine the BHN. (5)
5.2 Describe
the basic procedure of carrying out a Brinell test. (5)
5.3 Name
FOUR types of data that can be used in a tensile test. (4)
5.4 Draw
up a report on testing results. (6)
[20]
TOTAL:
100
memo
QUESTION 1
1.1 1.1.1 True (1)
1.1.2 False (1)
1.1.3 True (1)
1.1.4 True (1)
1.1.5 False (1)
1.1.6 False (1)
[6]
[6]
1.2 1.2.1 Strain (1)
1.2.2 Breaking (1)
1.2.3 Thermosetting (1)
1.2.4 Insulation (1)
1.2.5 Wear (1)
1.2.6 Shock (1)
1.2.7 Temperature (1)
1.2.8 Refractory bricks (1)
[8]
1.3 1.3.1 B (1)
1.3.2 C (1)
1.3.3 D (1)
1.3.4 A (1)
1.3.5 B (1)
1.3.6 C (1)
[6]
[20]
QUESTION 2
2.1 • Brittle
• Not
ductile
• Low
melting point
• When
molten it can be moulded or casted easily. (ANY
ONE) (1)
2.2 2.2.1 Above
0,5%
2.2.2 Brittleness, Difficult
to weld (ANY ONE) (1)
2.3 • Soft
• Heavy
• Ductile
• Loses
its shape under pressure (ANY
ONE) (1)
2.4
Aluminium
2.5
Grade 401
2.6
Underground
2.7
•
Nickel ore is first roasted.
• Then
it is melted in a furnace.
• The addition of limestone and quartz forms a slag which contains impurities.
• The addition of limestone and quartz forms a slag which contains impurities.
• The
nickel sinks to the bottom and is tapped off. (ANY THREE) (3)
2.8 Alloyed aluminium (1)
2.9 2.9.1 • Solder
• Plumbing
• Bullets
• Roof
covering (ANY
ONE) (1)
2.9.2
• Motor vehicle parts
• Aluminium
foil
• Gears
• Doors
and window (ANY
ONE) (1)
2.10 •
Alloying elements must be added to the plain carbon steel
• Change
and improve its properties (2)
2.11
Chromium (1)
2.12
2.12.1 It
generates heat. (1)
2.12.2
By applying a lubricant. (1)
2.12.3
•
It increases the life of the tool.
• It
enables faster working speeds.
• It
enables bigger cuts. (ANY ONE) (1)
2.13 Bearings. Electrical connectors. Springs. Musical
instruments. (ANY ONE) (1)
[20]
QUESTION 3
3.1 Advantages
Disadvantages
Lightweight Low strength
Ease and speed of manufacture. Low
dimensional stability.
Corrosion resistance Poor heat resistance.
Good electrical insulation. Poor weather resistance.
Good thermal insulation.
Colour and attractive appearance.
Pleasant to handle.
Low cost (ANY FOUR) (8)
3.2 • Exceptional resistance to extreme temperatures, over 480 °C.
• Resistance
to most chemicals.
• Water
resistance.
• High
dielectric strength.
• Poor
mechanical strength. (ANY FOUR) (4)
3.3 Bottles,
trays, buckets, motorcycle windshields, traffic signs, hoses, cable
coverings,
handbags, rainwater, gloves, gramophone records, upholstery
foam (ANY
FIVE) (5)
3.4
(3)
[20]
QUESTION 4
4.1 • Pig iron
• Grey
cast iron scrap
• Steel
scrap
• Coke
fuel
• Limestone
(ANY TWO) (2)
4.2
Iron ore (1)
4.3
Lime (1)
4.4 • The cylindrical furnace rotates slowly at approximately one revolution per minute.
4.4 • The cylindrical furnace rotates slowly at approximately one revolution per minute.
• It
is tilted to ease loading and discharge.
• A
primary jet of oxygen blows directly into the molten metal.
• A
secondary jet of oxygen blows above the molten metal (3) (ANY THREE)
4.5 4.5.1 The
Bessemer converter
Advantages Disadvantages
removes impurities in a short Uses normal air instead
length of time. of
oxygen.
Old technology no
longer in
widespread use. (3)
4.5.2
The arc furnace
Advantages Disadvantages
Can operate entirely on scrap no longer used
extensively.
And
produce good quality steel.
Can
be used for large or small
quantities. (3)
4.6
Yes (1)
4.7
Oil or water (1)
4.8
4.8.1 240
°C (1)
4.8.2 Dark straw (1)
4.9 • The workpiece is place in a box containing charcoal.
• The
box is sealed and gradually heated to about 925 °C.
• The
temperature is maintained for about 8 hours.
• The
steel is then removed and quenched in oil. (ANY
THREE) (3)
[20]
QUESTION 5
(5)
5.2 The Brinell tester uses a
steel or tungsten-carbide ball, which is pressed into the surface of the test material. You can use balls of different diameters
depending on the type of material that you are testing. You would generally use a ball with a large
diameter for hard materials and balls with a smaller diameter for softer
materials. The loads that are usually
used are 500 kg for soft metals such as copper and brass; 1 500 kg for
aluminium; and 300 kg for materials such as iron and steel. You usually apply the load for between 10 s and
15 s. (5)
5.3 • Ultimate tensile strength
• Yield
point
• Percentage
elongation
• Percentage
reduction of area (4)
5.4 • Objective of the test
• The
material being tested
• The
method of testing
• A summary of the test results - including tables, diagrams, graphs, data sheets etc.
• A summary of the test results - including tables, diagrams, graphs, data sheets etc.
• Findings
of the test - including comparisons to specifications etc.
• Name
of the person carrying out the test
• Date
of the test (6)
[20]
TOTAL: 100
[20]
TOTAL: 100
