Engineering Materials

2. ENGINEERING
MATERIALSE-MAT 111

3. 1. Describe in simple terms, the
production of pig iron from
iron ore.

4. • It is a semi-finished metal produced
from iron ore in blast furnace,
containing 92 percent iron, high
amounts of carbon, and balance
largely manganese and silicone plus
small amounts of phosphorus, sulfur,
and other impurities.

5. 2. Describe the principles of the
open hearth, the bessemer and
more modem processes.

6. • Is a batch process and a batch is called a
heat. The furnace is first inspected for
possible damage.
• Once it has melted, heavy scrap, such as
building, construction or steel milling scrap is
added, together with pig iron from blast
furnaces.

7. • A steel making process, now largely
superseded, in which carbon, silicon, and
other impurities are removed from molten
pig iron by oxidation in a blast of air in a
special tilting retort (A BESSEMER
CONVERTER).

8. •This process involves heating of
either blister steel fragments or
short lengths of wrought iron bars
mixed with charcoal inside fire
clay crucibles.

9. • This process wrought iron bars are
introduced in a furnace in between
powdered charcoal layers and are
subjected to a very high temperature for
about 700 degree celsius for about a
week to fortnight depending upon the
required quality of the steel.

10. • Electric arc furnaces are a firebrick lined
U-shaped vertical vessel in which scrap
steel is melted by an electric arc instead
of the usual fossil fuel. they are
sometimes used as mini-steel producers,
manufacturing steel products such as
structural steel rods and bars.

11. • CASTING

12. 3. Explain the differences between
sand casting, die casting, centrifugal
casting, forging, cold working and
hot rolled plate, bars and other
sections.

13. •The sand casting process involves
the use of a furnace, metal,
pattern, and sand mold. the metal
is melted in the furnace and then
ladled and poured into the cavity
of the sand mold, which is formed
by the pattern.

14. •It is a process in which objects
of a particular shape are
produced by forcing a molten
material into mold under
pressure.

15. • This is a casting technique that has
an extensive range of industrial
applications including the casting
of machine fittings where durability
of the finished product is
important.

16. • Is an ancient manufacturing prosses
used for metals that are difficult to be
machined or fabricated. This process
provides an excellent dimensional
accuracy and surface finish.

17. • Is the art of working metals by the
application of sudden blows or by steady
pressure. In these processes, the metal is
made to flow into the desired shape by
proper manipulationwith hammer or
presseither with or without the use of dies.

18. • Is a process in which metal is
shaped at a fairly low
temperature. This increases the
metals yield strength but makes it
less ductile.

19. • Is a mill process which involves rolling the
steel at a high temperature, which is
above the steels recrystallization
temperature. when steel is above the
recrystallization temperature, it can be
shaped and formed easily, and the steel
can be made in much larger sizes.

20. 4. State the normal range of carbon
content in mild steel, tool steel, cast
steel, and cast iron.

21. CARBON CONTENT
MILD STEEL 0.05% - 0.25%
TOOL STEEL 0.60-0.75%
CAST IRON 2% up
CAST STEEL 0.75%

22. 5. Describes the principle difference
between ferrous and non-ferrous
metals.

23. FERROUS METALS NON-FERROUS METALS
are naturally occuring inorganic
substances that contain iron as
an element in the composition.
are naturally occuring inorganic
substances that do not contain
iron as an element in the
composition.
it shows high magnetic
properties
do not show magnetic properties
are less resistant to corrosion are more resistant to corrosion
composed of mainly iron as
hydroxide, carbonates or
sulfides
are composed of various
elements and combinations
are composed of a high
percentage of iron
do not have iron in their
chemical composition.

24. 6. Gave examples of applications
of
non-ferrous materials in marine
engineering.

25. MATERIALS PROPERTIES USES
BRASS
GOOD WEARING,
ANTIFRICTION,CORROSION
RESISTANT
USED FOR MAKING PIPE
FITTINGS, TUBING, FILTER,
GAUGES, BEARING BUSHES
BRONZE
GOOD WEARING,
ANTIFRICTION,CORROSION
RESISTANT
USED FOR MAKING BEARING
BUSHES
PHOSPHER BRONZE
HAS GOOD TENSILE STRENGTH
AND RESISTANT CORROSION BY
SEAWATER
USED FOR BEARING AND GEARS
SOLDER
LOW MELTING POINT WHICH
DEPENDS UPON THE
PROPORTION OF CONSTITUENTS
USED FOR BEARINGS THE
MEATAL SHEETS
NAVAL BRASS
HAS HIGH STRENGTH AND
RESISTS CORROSION
USED FOR MARINE AND
ENGINEERING CASTINGS,
CONDENSER TUBES, PUMP
PARTS, MOTOR BOAT SHAFTINGS
MONEL METAL
HIGH CORROSION RESISTANCE,
EXCELLENT MECHANICAL
PROPERTIES
USED FOR CONDENSER TUBES
PROPELLERS, PUMP FITTINGS,
TURBINE BLADES

26. 7. State the purpose of the alloying
elements; nickel, chromium, and
molybdenum steels
used in marine engineering.

27. NICKEL
USED TO PROVIDE HARD WEARING
DECORATIVE AND ENGINEERING
COATINGS AS NICKEL PLATING.
WITH ITS RESISTANCE TO CORROSION BY
RAPIDLY FLOWING SEAWATER.
CHROMIUM
PISTON CROWN IS PLATED WITH
CHROMIUM FOR HEAT AND CORROSION
RESISTANCE
INTERNAL SURFACE OF CYLINDER LINER
IS PLATED WITH CHROMIUM TO REDUCE
CORROSION
MOLYBDENUM
IS USED IN STRUCTURAL STEELS
BECAUSE OF ITS CORROSION
RESISTANCE, STRENGTH AND DURABILITY.
SUCH STEELS ARE VERY USEFUL IN
PROTECTING METALS AGAINST CHLORIDE
CORROSION, THUS THEY ARE USED IN A

28. 8. Identify the metals used in non-
ferrous
alloys commonly employed in marine
engineering.

29. • CHROMIUM
• COBALT
• MOLYBDENUM
• TITANIUM
• NIO-BIUM
• TUNGSTEN
• MANGANESE