Various Steels In Civil Engineering Ahmad Sameer Nawab Kardan University Kabul, Afghanistan

1. Uses Of Various Steel In
Civil Engineering
BY:- Engr. Ahmad Sameer Nawab
Kardan University Kabul, Afghanistan

2. METALS
 Metals are the backbone of all engineering projects and products.
Various metals are used in one form or the other. Metals are found
as compounds like oxides, sulphates, carbonates, phosphates etc.
in nature.
 These compounds are known as ores. Ores are treated to remove
the impurities and get the metal .

3. •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.
METALS CHARACTERISTICS

4. METALS
Ferrous Non-Ferrous Alloys
Containing iron & Do not contain iron. A mixture of
almost all are e.g. aluminium, metals, or a
magnetic. copper, silver, gold, metal & small
e.g. mild-steel, lid, tin etc. amount of
cast-iron, tool- other substance
Steel etc.
Ferrous Alloys Non-Ferrous Alloys
e.g. e.g. brass (copper + zinc)
stainless steel bronze (copper + tin )
steel + chromium

5. OCCURRENCE OF IRON
 Iron is never available pure in nature. It has to be
extracted in the form of pig iron from the various iron
ores.
 Pig iron is the crudest and wrought iron is the purest
form of iron.
 The ores from which iron is extracted are:
i. Magnite : it contains 70 to 75% iron.
ii. Haematite : It has about 70% iron.
iii. Iron Pyrites: It has about 47% iron.
iv. Siderite: It contains 40% iron

6. PIG IRON
 To remove impurities from the iron ore carbon and flux are added
while melting it.
 The refined product so obtained is the crudest form of iron and is
called pig iron. It is cast into rough bars called pigs.
Properties:
 It is hard and brittle as such it is neither ductile nor malleable.
 It is difficult to bend.
 It melts easily. The fusion temperature is 1200 o C.

7. PIG IRON
 It can be hardened but not tempered.
 It can be magnetized.
 It has very high compressive strength but very weak in
tension.
 It does not rust.
 It cannot be welded.
USES: cast iron, wrought iron and mild steel are obtained
by refining the pig iron. Because of its high compressive
strength it is used in columns, base plates, door
brackets , wheel and pipe work.

8. CAST IRON
 Pig iron is remelted with limestone and coke and poured
into moulds of desired shapes and sizes to get purer
product known as cast iron.
 Moulding remelted pig iron removes impurity and gives a
more uniform product,
 Carbon contents in cast iron vary from 2 to 4.5%.

9. CAST IRON
PROPERTIES:
 Its structure is coarse crystalline and fibrous.
 Freshly fractured surface has grayish white appearance.
 It is brittle.
 It cannot withstand shocks and impacts.
 It cannot be welded.
 It cannot be magnetized.
 It does not rust.
 It is fairly hard and cannot be worked with a hand file.

10. CAST IRON
USES:
 It is used for casting, rain water pipes, gratings, railings,
balustrades( staircase side railing).
 Because of high compressive strength it is used in
making columns, supports for heavy machinery, carriage
wheels etc.
 It is the basic material for the manufacturing of Wrought
iron and steel.

11. WROUGHT IRON
 If all the carbon and other elements in pig iron are
oxidized and may be left with 0.25 percent of carbon
then we obtain wrought iron.
 It is by far the purest form of iron in which the total
impurities do not exceed 0.5%.
PROPERTIES:
 Its structure is fibrous and has silky luster.
 It is ductile and malleable.
 It is tough and can withstand shocks and impact better
than cast iron.

12. WROUGHT IRON
 It can be forged and welded.
 It rusts easily
 It is unaffected by saline water.
 It cannot be permanently magnetized.
USES :
It is used in making roofing sheets, corrugated
sheets, rods, gas and water pipes, boiler tubes and
ornamental iron works such as grills gates and railing
and window guards.

13.  Gates

14.  Windows

15.  Railings and fence

16. STEEL
 The essential difference between cast iron and steel is
the amount of their carbon contents.
 Steel goes on becoming harder and tougher with the
increase in its carbon contents.
 Up to a content of 1.5% all the carbon gets into
chemical combination with iron and none of its exist in
free state.
 If carbon contents increase beyond 1.5% then it does
not combine with iron and is present as free graphite. At
this stage metals falls in a category of cast iron.

17. STEEL
 For a material to be classified as steel there should be
no free graphite in its composition.
 If there is any free graphite in it then it falls in the
category of cast iron.

18. CLASSIFICATION OF STEEL
 Depending upon carbon content steel is classified into
following categories.
Steel Carbon content
1. Dead steel < 0.15%
2. Mild steel 0.15 to 0.3%
3. Medium carbon steel 0.3 to 0.8%
4. High carbon steel 0.8 to 1.5%
High carbon steel with carbon percentage over 1% is also
known as cast steel or carbon tool steel

19. MILD STEEL
 Steel where carbon content is 0.15 to 0.3% is called
mild steel, low carbon steel or soft steel.
 It is ductile and malleable.
 It is more tough and more elastic than wrought iron and
cast iron. It corrodes easily.
 It is equally strong in tension and compression.

20. MILD STEEL(USES)
1. In construction work it is chiefly used as rolled structural
sections like I-section, T-section, angle iron.
2. Mild steel round bars are extensively being used as
reinforcement in reinforced cement concrete.
3. Plain and corrugated sheets of mild steel are used as roof
covering.
4. It is also used in the manufacturing of various tools and
equipments, for rail track, transmission towers and industrial
building.

21. T-section

22. I-section

23. Angle iron

24. HIGH CARBON STEEL
 In this steel the carbon contents is between 0.55 to
1.5%. High percentage of carbon in it renders it harder
and tougher.
 It is more tough and elastic then mild steel.
 Comparatively it is more stronger in compression than in
tension.
 It withstand shocks and vibrations

25. HIGH CARBON STEEL
1. It is used in making tools such as drills, files and
chisels.
2. Fine quality of cutlery is made of high carbon steel.
3. It is used to manufacture those parts of machinery that
need a hard, tough, durable material capable of
withstanding shocks and vibration

26. Drills

27. Files

28. Chisels

29. HIGH TENSION STEEL
 It is essentially a low carbon steel and the percentage of
carbon is kept lesser than 0.15%. It is also termed as
high tension steel.
 Because of increase tensile strength, lesser weight of it
used, as compared to mild steel at the same job. The
structure thus becomes lighter.
 It withstand atmospheric corrosion better. It is tougher
and more elastic. It is more brittle and less ductile then
mild steel.
 High tension steel wires are extensively used in
reinforcing prestressed concrete structures.

31. REINFORCING STEEL
 Plain cement concrete being strong in compression but
weak in tension.
 Mild steel or high tension steel is embedded as
reinforcement in the concrete to make it stronger in
tension.
 Though flats and square bars can be used as
reinforcement yet the round bars are extensively used
for the purpose