Steel as a material

1. AGENDA
Topic one
Topic two
Topic three
Topic four
Topic five
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2. STEEL AS A
MATERIAL

3. DEFINITION:
Steel is a strong and versatile metal. It is an
alloy consisting of iron with a small amount of
carbon and occasionally other elements.

4. CHARACTERSTICS OF STEEL
1.Strength: Steel is a high-strength material, particularly in tension, and can
be used for structural loads.
2.Durability: Steel is highly durable with a potential lifespan of over 100
years. It does not swell or creep, instead remaining very rigid.
3.Versatility: Steel is an incredibly versatile material. Its many grades can be
applied to thousands of uses.
4.Machinability: Most steel is easily machinable, depending on the grade.
Some specific grades of steel (free-cutting steels) are highly machinable.
5.Weldability: Most grades of steel are easily weldable, although some need
specialized welding procedures.
6.Corrosion Resistance: Steel can be alloyed with other elements such as
chromium, nickel, and molybdenum to better resist corrosion.
7.Conductivity: Steel generally has lower thermal and electrical conductivity
compared to other metals. It can be employed as a strong and heat-resistant
shielding material.
8.Recycling: Steel can be completely recycled, and due to its value, a large
portion (>60%) of steel globally is recycled.
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5. HOW STEEL IS
USED IN
BUILDINGS AND
INFRASTRUCTU
RE

6. FOR BUILDINGS
Structural sections:
these provide a strong, stiff
frame for the building and
make up 25% of the steel use
in buildings.
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7. FOR BUILDINGS
Reinforcing Bars:
these add tensile strength and
stiffness to concrete and make
up 44% of steel use in
buildings. Steel is used
because it binds well to
concrete, has a similar thermal
expansion coefficient and is
strong and relatively cost-
effective. Reinforced concrete
is also used to provide deep
foundations and basements
and is currently the world’s
primary building material.
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8. FOR BUILDINGS
Sheet products:
31% is in sheet products
such as roofing, purlins,
internal walls, ceilings,
cladding, and insulating
panels for exterior walls.
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9. FOR BUILDINGS
Non-structural steel:
steel is also found in many
non-structural applications in
buildings, such as heating
and cooling equipment and
interior ducting.
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Non-structural steel:
Internal fixtures and fittings
such as rails, shelving and
stairs are also made of steel.

10. FOR INFRASTRUCTURE
Transport networks:
steel is required for bridges, tunnels,
rail track and in constructing buildings
such as fueling stations, train stations,
ports and airports. About 60% of steel
use in this application is as rebar and
the rest is sections, plates and rail
track.
Utilities (fuel, water, power):
over 50% of the steel used for this
application is in underground
pipelines to distribute water to and
from housing, and to distribute
gas. The rest is mainly rebar for
power stations and pumping
houses.
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11. DIFFERENT TYPES OF STEEL
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CAST IRON- WROUGHT IRON- MILD STEEL-
STAINLESS STEEL

12. DIFFERENCE
BETWEEN
CAST AND
WROUGHT
IRON
CAST IRON WROUGHT IRON
Cast iron is iron that is melted and poured into a
Cast Iron is a type of iron-carbon alloy known for
its high carbon content (2-4%) and low melting
point.
Wrought Iron is nearly pure iron with a carbon
content of less than 0.1%.
It is produced by melting iron and adding carbon,
which allows it to solidify into a cast mould.
It is produced by heating cast iron and manually
removing impurities to create a fibrous structure.
Cast Iron is known for its excellent castability,
making it ideal for intricate designs and shapes.
Wrought Iron is renowned for its malleability,
ductility, and corrosion resistance.
Cast Iron is brittle, hard and non-malleable.
Wrought iron is ductile, malleable and can be
heated again and again so that one could work
on it so as to give it shape.
Cast Iron is good for indoor decoration
Wrought Iron is good for outdoor and indoor
decoration purpose. Wrought Iron can withstand
extreme weather conditions and not corrode or
rust easily.
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13. 13

14. MILD STEEL STAINLESS STEEL
Mild steel, just like all carbon steel, is an alloy of
iron (base element) and carbon (alloying
elements) mixed with traces of other chemical
elements.
Stainless steel is a form of steel alloy that has one
essential characteristic—high corrosion
resistance. This characteristic is attributed to the
high chromium content, which ranges from 10.5%
to 20% by weight.
Carbon
Content
Mild steel is low-carbon steel, with a low carbon
content ranging from 0.05% to 0.25%.
Stainless steels contain less than 1.2% carbon,
which is a comparatively low amount.
Chemical
Composition
Mild steel consists primarily of iron and carbon as
two main elements. Other elements like Nickel,
chromium, aluminium, phosphorus, sulfur, silicon,
and others are present in trace amounts, but what
makes mild steel different is its carbon content.
Stainless steel, on the other hand, contains
significant amounts of alloying elements besides
carbon. The most significant among these are
chromium and nickel, a minimum of 10.5% and
8% by weight, respectively. These elements make
the stainless steel corrosion-resistant and more
formable and weldable.
Strength
Mild steel has a rather low tensile strength
compared to stainless steel, but it can be
strengthened by adding carbon.
stainless steel is generally stronger than mild
steel.
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DIFFERENCE
BETWEEN
MILD AND
STAINLESS
STEEL

15. MILD STEEL STAINLESS STEEL
Corrosion
Resistance
mild steel needs further processing, such as
galvanizing or painting, to give it a protective
surface. This type of steel actually corrodes very
rapidly as iron reacts and bonds with oxygen from
the atmosphere to create iron oxide.
stainless steel is a rather corrosion-resistant
material. The added chromium bonds with the
oxygen from the atmosphere, thus preventing the
iron within the alloy from oxidizing. This prevents
the steel from rusting, giving stainless steel its
corrosion-resistant properties.
Ductility
Mild steel is pretty ductile due to its low carbon
content, making it suitable for producing pipes and
pipe fittings.
Stainless steel is less ductile compared to mild
steel.
Hardness
Mild steel can be strengthened with extra carbon
or galvanized with zinc. Without this, the mild steel
itself remains extremely pliable and prone to
damage without galvanization.
stainless steel becomes particularly impact-
resistant because of the chromium alloy that
shields it.
Weldability
and
Malleability
mild steel is generally more malleable due to its
ductility.
stainless steel contains nickel which improves
weldability.
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DIFFERENCE
BETWEEN
MILD AND
STAINLESS
STEEL