ferrous and non-ferrous metals -...
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Product Design
Ferrous and Non-Ferrous Metals
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Learning objectives
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Le
arn
ing
ob
jecti
ves
To understand where metals come from and how
they are prepared for use.
To look at examples of ferrous metals, non-ferrous
metals and alloys, and to know the properties of
different metals.
To understand how heat treatment can change the
properties of metals.
To be able to use hand tools to work with metals.
To be familiar with the industrial processes used to
manufacture metal goods.
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Metals are common in manufacturing today. From
building and construction work to vehicles and
leisure products, they are a vital material for product
designers and engineers.
The elements of all metals are found naturally
in the earth. However, they need to be extracted
and processed before they can be used for
manufacturing purposes.
Because metals in their most basic form are
natural resources, designers and
manufacturers need to be careful and
socially responsible about how much they use,
and reuse or recycle metals where possible.
Background on metals
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Metals form part of the earth’s crust as metal ore. To obtain
useful metals, the metal ore is mined and washed to
remove other minerals and unwanted materials.
Iron ore is the basis for most steels. To extract pure iron the
iron ore is heated in a furnace in a process known as
smelting.
Where do metals come from?
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Primary processes – rolling
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Primary processes – extrusion
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Metals are available in several raw forms. Each form is
suitable for different manufacturing processes depending on
the type of equipment used, the cost of the metal, the scale
of production and the properties of the finished product.
Stock forms of metals
octagonal
hexagonal
square
round rod
sheet
flat strip round tube
square tube
angle
channel
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Metals can be broken down into these main categories:
Non-ferrous
metals
Ferrous
metals
Allo
ys
Allo
ys
Pu
re m
eta
ls
Pure metals do
not contain any
other metals or
elements.
Categories of metals
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Ferrous metals are obtained from iron ore. You might
recognize the letters ‘Fe’ from the periodic table, where they
represent iron.
Iron replaced bronze as the
principal metal by 1000 BC.
Early pots and pans made from
iron poisoned the users!
Early steels were made by
adding carbon to iron as it was
melted over a charcoal fire.
Ferrous metals
Ferrous metals:
contain iron
will corrode unless
protected
are attracted by a
magnet
are strong, rigid
and cheap.
Ferrous facts
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A closer look at ferrous metals
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Non-ferrous metals do not contain iron. These are pure
metals used by designers, manufacturers and engineers in
a wide variety of applications.
Aluminium is the most common
non-ferrous metal, found in
abundance in bauxite ore.
Non-ferrous metals are not
magnetic.
Non-ferrous metals
Non-ferrous metals:
contain no iron
are not attracted
by a magnet.
Non-ferrous facts
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A closer look at non-ferrous metals
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Sometimes ferrous and non-ferrous metals require different
properties in order to function better in specific situations.
Alloying metals involves mixing two or more metals and
other elements to improve their properties.
Alloys
Alloying metals can:
lower the melting point
alter thermal and electrical properties
make a material harder for cutting purposes
improve resistance to corrosion
help metal to flow better into a cast.
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A closer look at alloys
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Random alloy generator
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Metals and their properties
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Changing the properties of metals
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Heat treatment – hardening steel
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Heat treatment – tempering
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Heat treatment – annealing
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Working with metals – hand tools
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Milling machines are used to remove thin
layers from a billet (block of material)
which is clamped to the bed (base) of the
machine. The material is fed past a cutting
tool which has many sharp teeth and can
remove material quickly.
Industrial processes
When manufacturers want to make
cylindrical products, they use a centre
lathe. Metals and plastics can be used
on this machine. The work is held in a
chuck and a cutting tool is moved
towards the work while being held in a
tool holder, mounted on the tool post.
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Several surface finishing techniques can be used on metals.
The most common ones are detailed below:
Paint
Plastic Coating
Lacquering
Enamelling
Surface must be smooth and
de-greased
Primer required
Hammerite is a good one-coat
metal paint.
Suitable for most metals
Object is heated and dipped in a
tank of powder paint
Object is returned to oven to
ensure a smooth, glossy finish.
Helps to prevent corrosion
after polishing
A layer of cellulose or varnish
is applied
Often used on jewellery.
Powdered glass is melted
onto the metal surface
Provides a hard (but brittle)
finish with different colours
and textures.
Finishing techniques
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Key points
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Ke
y p
oin
ts
Metals are extracted from the earth’s crust and then
prepared into standard shapes before being sold to
manufacturers.
Ferrous metals are obtained from iron ore and
include cast iron and steel. Non-ferrous metals
include aluminium, copper and tin.
Alloys, such as brass and stainless steel, are formed
from two or more metals and other elements.
Different elements alter the properties of metals.
Heating metals also alters their properties.
Metals can be worked with hand and machine tools,
including milling machines and centre lathes.