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8/10/2019 Properties of Iron and Steels
1/25
GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
8/10/2019 Properties of Iron and Steels
2/25
GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
Keywords:Alloy, carbon steels, low-alloy steels, high-alloysteels
Prior Learning:
Identify & explain different extraction processes
8/10/2019 Properties of Iron and Steels
3/25
GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
Learning Objectives:
By the end of the lesson I can:
The properties of pig iron and how this limits its usefulness.
Pig iron is the intermediate product o f smelt ing iron o re with
coke. Pig iron has a very hig h carbon content, typ ical ly 3.5
4.5%, which makes it very b ri t t le and not u seful direct ly as amater ial except for l im ited app l icat ions .
That iron can be alloyed to make it more useful.
Explain how the properties of alloys (but not smart alloys)
are related to models of their structures.
8/10/2019 Properties of Iron and Steels
4/25
GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
What are the properties of different metals?
8/10/2019 Properties of Iron and Steels
5/25
GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
gold (Au): This metal is unreactive. This is represented byhaving the band on stage, not mixing with the other elements
and not doing very much. lead (Pb), zinc (Zn) and copper (Cu): These metals are heavy
metals and are dressed up as heavy metal rockers.
copper (Cu): This metal has been drawn into wires.
aluminium (Al) and titanium (Ti): These metals are reactive.In this scene, they are getting overexcited and knocking over atable.
iron (Fe): This metal has rust patches and is struggling to liftthe bar stools.
steel (Fe wearing nerves of steel T shirts):These metalalloys have carbon atoms on their shoulders to show that theyare alloys. The steel is shinier than the iron atom. Steel is easilylifting the bar stools that iron was unable to lift because it isstronger.
8/10/2019 Properties of Iron and Steels
6/25
GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
Lets go back in time 3 years to
Year 7
YEAR 10
YEAR 7
And draw (or
make a
model toshow) the
atom
arrangement
in a solid
Now add a
different
sized particleto your
model. What
is this
called?
8/10/2019 Properties of Iron and Steels
7/25GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
What are the general properties of most metals?
solid at room temperature
Why do metals have these particular properties?
high melting point
good conductors of electricity and heat
malleable: they can be shaped
ductile: they can be drawn into wires
strong
dense
8/10/2019 Properties of Iron and Steels
8/25GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
sea of electrons
metal ions
The atoms in a pure metal are in
tightly-packed layers, which form
a regularlatticestructure.
The outer electrons of the metal
atoms separate from the atoms
and create a sea of electrons.
These electrons are delocalized
and so are free to move through
the whole structure.
The metal atoms become positivelycharged ions and are attracted to
the sea of electrons. This attraction
is called metallic bonding.
8/10/2019 Properties of Iron and Steels
9/25GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
How does the sea of electrons affect the properties of metals?
8/10/2019 Properties of Iron and Steels
10/25GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
Delocalized electrons in metallic bonding allow metals to
conduct heat and electricity.
This makes heat transfer in
metals very efficient.Delocalized electrons also
conduct electricity through
metals in a similar way.
For example, when a metal is
heated, the delocalized electrons
gain kinetic energy.
These electrons then move fasterand so transfer the gained energy
throughout the metal.
heat
8/10/2019 Properties of Iron and Steels
11/25GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
Metals are usually strong, not brittle. When a metal is hit,
the layers of metal ions are able to slide over each other,
and so the structure does not shatter.
The metallic bonds do not break because the delocalized
electrons are free to move throughout the structure.
metal after it is hit
forceforce
This also explains why metals are malleable (easy to shape) and
ductile (can be drawn into wires).
metal before it is hit
8/10/2019 Properties of Iron and Steels
12/25GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
E d k h f l (
8/10/2019 Properties of Iron and Steels
13/25GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
Investigating Alloys
How would you investigate the strength of alloywires?
What will you change? (The independent variable)
What will you measure? (The dependent variable)
How would you make it a fair test? (Controlledvariables)
E D d k h 3 f l ( b
8/10/2019 Properties of Iron and Steels
14/25GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
On a plain piece of paper add information
from the following slides to create a mindmap on iron including;
Alloying
Extraction
Properties
Chemical information
(Anything else you wish to include)
E i Y DO d k h 3 i f l ( b
8/10/2019 Properties of Iron and Steels
15/25GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
Most iron is converted into
steels.
Removing all impurities wouldproduce pure iron. Pure iron has a
regular arrangement of atoms, with
layers that can slide over each
other, and so is soft and easily
shaped, but too soft for many uses.
The iron collected from a blast furnace is only
96% pure.
molteniron
hot air
moltenslag
raw materialsUsually, this product will be treated
further because the impurities make
iron brittle.
E ti Y DO d t k th 3 i t f t l ( b
8/10/2019 Properties of Iron and Steels
16/25GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
Steel is an alloy of ironand other elements, including carbon,
nickel and chromium.
Steel is stronger than pure iron and can be used for
everything from sauce pans to suspension bridges!
E ti Y DO d t k th 3 i t f t l ( b
8/10/2019 Properties of Iron and Steels
17/25GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
The atoms of other elements are
different sizes. When other elementsare added to iron, their atoms distort
the regular structure of the iron atoms.
The atoms in pure iron are arranged
in densely-packed layers. These
layers can slide over each other. Thismakes pure iron a very soft material.
It is more difficult for the layers of iron
atoms in steel to slide over each other
and so this alloy is stronger than pure
iron.
8/10/2019 Properties of Iron and Steels
18/25
E ti Y DO d t k th 3 i t f t l ( b
8/10/2019 Properties of Iron and Steels
19/25
GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
Steel is not a single substance & there are lots
of different steels all being an alloy of iron with
either carbon and/or other elements.
low carbon steelcontains less than 0.25% carbon
Soft and easily shaped. Not as strong as high carbon steel
but less likely to shatter.
high carbon steelcontains more than 0.5% carbon.
Very strong but brittle.
1. CARBON STEEL: made by alloying Fe
with small amounts of C (from 0.03-1.5%).
They are the cheapest to make & are used for
car bodies, knives, ships, machinery,containers, structural steel for buildings.
E m ti ; Y DO d t k th 3 m i t f t l ( b
8/10/2019 Properties of Iron and Steels
20/25
GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
Nickel-steelvery resistant to
stretching forces so are used for long-
span bridges, military armour-plating
Tungsten-steeloperates well under very hot conditions so
it is used to make high-speed tools.
2. LOW-ALLOY STEEL: made by
alloying Fe with small amounts of other
metals (from 1-5%). They are moreexpensive & may contain metals like Ni,
Cr, Mn, V Ti and W. Each giving a
different property.
Exam tip; You DO need to know the 3 main types of steel (carbon
8/10/2019 Properties of Iron and Steels
21/25
GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
Chromium-steelstrong withchemical stability it is mixed with
between 12-15% Cr and often some Ni
This is also known as stainless steelThese are used to
make cooking utensils & cutlery, chemical reaction vessels
because they combine hardness & strength with a resistance to
corrosion (they do not rust!)
3. HIGH-ALLOY STEEL: made by alloying
Fe with large amounts of other metals.
They are EVEN more expensive & maycontain metals like Ni, Cr, Mn, V Ti and W.
Each giving a different property.
Exam tip; You DO need to know the 3 main types of steel (carbon
8/10/2019 Properties of Iron and Steels
22/25
GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
Exam tip; You DO need to know the 3 main types of steel (carbon
8/10/2019 Properties of Iron and Steels
23/25
GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
Exam tip; You DO need to know the 3 main types of steel (carbon
8/10/2019 Properties of Iron and Steels
24/25
GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
Refs Decision
If its true it stays, if its false SEND IT OFF!
Yellow = TRUE, Blue = FALSE
Steel is a mixtureAll steels contain cobalt (Co)
Stainless steels are expensiveStainless steels rust because
they contain iron
The molecular formula forsteel is St
Exam tip; You DO need to know the 3 main types of steel (carbon
8/10/2019 Properties of Iron and Steels
25/25
GCSE Core Chemistry
Exam tip; You DO need to know the 3 main types of steel (carbon,low-alloy & high-alloy) & identify what they contain
Learning Objectives:
By the end of the lesson I can: The properties of pig iron and how this limits its usefulness.
Pig iron is the intermediate product o f smelt ing iron o re with
coke. Pig iron has a very hig h carbon content, typ ical ly 3.5
4.5%, which makes it very b ri t t le and not u seful direct ly as amater ial except for l im ited app l icat ions .
That iron can be alloyed to make it more useful.
Explain how the properties of alloys (but not smart alloys)
are related to models of their structures.