WHAT ARE METALS
Learning Objectives:
•Defining METAL?
•Different Types of Metals – Ferrous, Non-Ferrous, Alloys
•Main focus of Ferrous Metals
•Properties of Metals
•Characteristics of Ferrous Metals with daily examples
•Advantages/Disadvantages of Ferrous Metals
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Contd..METALS
•Metals are…
Solid at room temperature, except
mercury, which is liquid !
•Metals have…
very high melting point.
•Metals are…
shiny when they cut.
•Metals are…
good conductors of heat and electricity.
•Metals are…
usually strong & malleable so they can be
hammered into shape.
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METALS in Periodic
Table
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METALS
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METALS
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METALS
Ferrous
Containing iron &
almost all are
magnetic.
e.g. mild-steel,
cast-iron, toolSteel etc.
Ferrous Alloys
e.g.
stainless steel
steel + chromium
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Non-Ferrous
Do not contain iron.
e.g. aluminium,
copper, silver, gold,
lid, tin etc.
Alloys
A mixture of
metals, or a
metal & small
amount of
other substance
Non-Ferrous Alloys
e.g. brass (copper + zinc)
bronze (copper + tin )
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METALS
METALS & ALLOYS
Metals are available in pure or alloy form.
Pure Metals such as pure aluminium or pure copper, contain
only one type of metal. They are not mixed with any other
metal.
Alloys are mixture of two or more pure metals.
Alloys tend to have better strength properties than pure
metals.
Alloys and pure metals often have special physical
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properties.
PROPERTIES OF METALS
1.
Strength - The ability of a material to stand up to
2.
Elasticity - The ability of a material to absorb force
3.
Plasticity - The ability of a material to be change in
forces being applied without it bending, breaking,
shattering or deforming in any way.
and flex in different directions, returning to its original
position.
shape permanently.
4.
Ductility - The ability of a material to change shape
(deform) usually by stretching along its length.
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PROPERTIES OF METALS
Tensile Strength – The ability of a material to stretch
5.
without breaking or snapping.
6.
Malleability - The ability of a material to be reshaped
7.
Toughness - A characteristic of a material that does
8.
Conductivity - The ability of a material to conduct
in all directions without cracking.
not break or shatter when receiving a blow or under a
sudden shock.
electricity.
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PROPERTIES OF METALS
9.
Hardness – The ability of a material to resist scratching,
wear and tear & indentation.
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FERROUS-METALS
1.
Mild Steel
Composition: Iron alloy with 0.3% carbon
Properties: Malleable and ductile, and therefore bends fairly easily
Uses: nuts, bolts, screws, tubes etc.
1.
Methods of Identification
Appearance: Bright drawn mild steel has a smooth, bright surface;
black mild steel is covered with a blue-grey oxide
Dropping: Gives out a ringing note
Grinding: Gives off a shower of long white sparks
Effect of Heating: Slightly tougher but little change
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FERROUS-METALS
2.
Tool Steel / cast steel / carbon steel
Composition: Iron alloy with 0.5%-1.5% carbon
Properties: Tough rather than hard, and fairly ductile
Uses: Springs and most tools such as hammer heads, drills,
chisels,
shears etc
Methods of Identification
Appearance: Has a smooth skin of black oxide
Dropping: Gives out a high ringing note
Grinding: Moderate number of red sparks
Effect of Heating: Becomes hard and brittle
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FERROUS-METALS
3.
cast iron
Composition: Iron alloy with 2%-4% carbon
Properties: Brittle, snaps before it will bend. Strong in compression
Uses: Vices, cylinder blocks for car engines, frames for most
machines
Methods of Identification
Appearance: Grey with a granular surface
Dropping: gives out a dull note
Grinding: Gives off a few dull sparks
Effect of Heating: No change
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ADVANTAGES OF FERROUS METALS
1.
High strength to weight ratio
it minimise the substructures cost, which beneficial in poor ground
condition. E.g. The Newark Dyke Rail Bridge – comprises 77 meter
long, 11.25 meter wide bowstring with 820 tonnes of S355 steel.
This bridge use IMD (Interactive Model Technique) – reduced the
time required to assess the dynamic response of the structure.
This bridge was the first UK steel bridge to be designed for the next
generation of 225 km/hr trains.
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ADVANTAGES OF FERROUS METALS
2.
High quality material
readily available worldwide in various certificate grades.
3.
Speed of construction
4.
Versatility
steel suits range of construction methods & sequences.
5.
Modification & repair
6.
Recycling
7.
Durability
8.
Aesthetics
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steel has a broad architectural possibilities.
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DISADVANTAGES OF FERROUS METALS
1.
2.
3.
Costly waste
High cost of final finishing & polishing
Environmental issue
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REVIEW
•
•
•
•
•
•
Metal
Different types of metals – ferrous, non-ferrous, alloy
Properties of metals
Strength
Elasticity
Plasticity
ductility
tensile strength
malleability
toughness
conductivity
hardness
Examples of ferrous metals, uses, methods of identification
Advantages
Disadvantages
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Mid Term Exam
• Monday 2/10/2012, from 15 to 17
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