Metals - Design Technology

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Metals
•
All metals belong to one of these two groups.
•
Ferrous metals are metals, which are mainly made of iron with small
amounts of other metals or elements added in order to give the correct
properties. Almost all ferrous metals are magnetic and can be picked
up with a magnet. These metals rust or oxidise if not treated as they
contain iron.
•
Non-Ferrous metals are those metals, which do not contain iron.
These metals are not magnetic and cannot be attracted by a magnet.
Examples of these are aluminium, copper, lead, zinc and tin. These
metals do not oxidise as they do not contain iron.
Pure metals and alloys
•
All metals fall into two categories. They can either be pure metals or
alloys.
•
A pure metal consists of a single element, which means that it is a
metal only having one type of atom in it. The most commonly used pure
metals are aluminium, copper, iron, lead, zinc, tin, silver and gold.
•
An alloy is a mixture of two or more pure elements. Pure metals
sometimes lack certain required properties. To create these properties a
number of these pure metals are combined together.
•
Pure aluminium is rarely used because it is too soft. It is normally mixed
with other metals, which produce aluminium alloys that are even
stronger than mild steel, are resistant to corrosion but still retain the
lightness of aluminium.
Name the metals?
• Mild steel. It is used for general
structural work for example
girders, nuts, bolts, screws, car
body panels and non-cutting
tools.
• If mild steel is coated in tin it is
called ‘Tin plate’.
• If mild steel is coated in zinc it is
called ‘Galvanised sheet’.
• If mild steel is coated in lead it is
called ‘Terne sheet’.
Name the metals?
• Aluminium. It is used to
make car bodies, cooking
utensils, engine cylinder
heads, window frames,
insulation, foil food
wrapping and boats.
Name the metal being poured?
To give you a clue it is used to make
window frames and aircraft.
• It is mixed with copper to
make an alloy. This alloy is
much stronger than pure
aluminium.
• Duralumin is used to make
parts of aircraft.
Name the metals?
Medium carbon
steel. It is used to
also make garden
tools, axles and
shafts.
Name the metal used to make
the rear sprocket on this bike?
Name the metals?
• High Carbon Steel. It
is used to make hand
tools, chisels and
punches. It is also
called tool steel.
Name the metal used to
make this centre punch?
Material
Type
Uses
Properties
Mild steel
Ferrous
metal
Nails, screws, nuts and
bolts, girders, car bodies
Tough, malleable, high tensile
strength, easily joined, poor
resistance to corrosion,
general-purpose metal.
Brass
Nonferrous
metal
Ornaments, boat fittings,
castings.
Corrosion resistant, polishes
well. Hard, easily joined, good
conductor of heat and
electricity.
Copper
Nonferrous
metal
Hot water storage
cylinders, central heating
pipes, electrical wires,
copper clad electronics
boards
Good conductor of heat and
electricity, corrosion resistant,
easily joined, polishes well,
solders and brazes well,
expensive to buy.
Stainless
steel
Alloy
Sinks, cutlery, dishes,
teapots
Hard and tough, resists wear,
corrosion resistant, difficult to
cut and file.
Aluminium
Nonferrous
metal
Kitchen cooking utensils,
pans, packaging, cans,
window frames
High strength to weight ratio,
light, soft, difficult to join, good
conductor of heat and
electricity, corrosion-resistant,
polishes well.
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