production Engineering

1. Ferro-electricity
 Ferro-electricity is defined as the spontaneous alignment
of electric dipoles by their mutual interaction in the
absence of an applied electric field.
 This arises from the fact that the local field increases in
proportion to the polarization. Thus, ferro-electric
materials must posses permanent dipoles. Ex.: BaTiO3,
Rochelle salt (NaKC4H4O6.4H2O), potassium dihydrogen
phosphate (KH2PO4), potassium niobate (KNbO3).
 These materials have extremely high dielectric constants at
relatively low applied field frequencies.
 Thus, capacitors made from ferro-electric materials are
smaller than capacitors made of other dielectric materials.

2. Piezo-electricity
 Piezo-electricity, or pressure electricity, is defined as
polarization induced by the application of external force.
 Hence, by reversing the direction of external force, direction
of the field can be reversed i.e. the application of an
external electric field alters the net dipole length and causes
a dimensional change.
 This property is characteristic of materials having
complicated structures with a low degree of symmetry.
 Thus, piezoelectric materials can be used as transducers –
devices that convert mechanical stress into electrical energy
and vice versa.
 Application for these materials includes microphones,
ultrasonic generators, sonar detectors, and mechanical
strain gauges. Ex.: Barium titanate, lead titanate, lead
zirconate (PbZrO3), ammoinium dihydrogen phosphate
(NH4H2PO4), and quartz.

3. IES-1993
Quartz is a
(a) Ferroelectric material
(b) Ferromagnetic material
(c) Piezoelectric material
(d) Diamagnetic material

4. Welding cracks
 Cracks may occur at the following locations :-
(i) In the weld (Fuse) Metal Zone
(ii) In the Base metal zone
(iii) Sometimes, the cracks originate in one Zone and
then spread to the other Zone.
Contd…

5.  Cracks in the base metal usually occur at low
temperatures (around 200°C) and are known as Cold
cracks.
 On the other hand, the cracks in the weld metal zone
occur while the metal is still very hot. Such cracks are
called Hot cracks.
 Cracks in the weld may be due to structural stresses in
the metal (for example, the formation of martensite),
heavy shrinkage, extra high amount of sulphur,
phosphorous or carbon in the metal, excessively rigid
clamping of the parts being welded or the presence of
gases in the weld metal.
Contd…

6.  Cold cracking can occur due any to the following
several factors :- improper welding conditions, the
presence of gas and other impurities in the weld,
wrong choice of filler rod and metallurgical factors
such as excessive cooling rate resulting in the
formation of martensite and formation of brittle
phases in the weld when cold or the formation of
phases which are brittle at high temperatures
[Allotropic transformations].
 Cracks in the base metal can occur due to the
following reasons :- Corrosion, Base metal defects,
Base metal composition variations, hydrogen
embrittlement and internal stresses set up due to
restrained shrinking after welding.

7. IES-2005
Hot cracks occur in the weld and fusion zone as the
metal solidifies. Which of the following are the causes
for hot cracks?
1. Presence of sulphur and phosphorus in the base metal
2. High carbon or alloy content of the base metal
3. Moisture in the joint or electrode
4. Joint restraint
Select the correct answer using the code given below:
(a) 1, 2 and 4 (b) 1, 2 and 3
(c) 3 and 4 (d) 1, 2, 3 and 4

8. H-embrittlement and Passivity
 Hydrogen embrittlement is form of failure than
corrosion,but occurs as a result of hydrogen produced
during corrosion. Atomic hydrogen diffuses into crystals
and inhibits dislocation motion, causing failure.
 Counter measures: heat treatment; removal of hydrogen
source.
 Passivity: It is form protection against corrosion. It results
from thin, strong adherent oxide layer formed over the
surface. Usually observed in Al, Cr, Fe, Ni, Ti and their
alloys. Passive layers may get damaged during mechanical
vibrations, and so these metals are prone to erosion
corrosion.

9. IES-1992
Presence of hydrogen in steel causes
(a) Reduced neutron absorption cross-section
(b) improved weldability
(c) Embrittlement
(d) corrosion resistance

10. Other questions

11. IES-2006
In case of power screws, what is the combination
of materials used for the screw and the nut?
(a) Cast iron screw and mild steel nut
(b) Carbon steel screw and phosphor bronze nut
(c) Cast iron screw and cast iron nut
(d) Aluminium screw and alloy steel nut

12. IES-1992
For the pipe fitting like elbow, tee, union etc.
which of the following is preferred?
(a) Pig iron
(b) Malleable iron
(c) Spheroidal graphite cast iron
(d) High carbon steel

13. IES-1992
Which of the following display properties similar
to that of steel
1. Black-heart cast iron
2. White-heart cast iron
3. Gray cast iron
4. Pig iron
(a) 1 and 2 only (b) 3 and 4 only
(c) 2 and 4 only (d) 1 and 3 only

14. IES-1992
Addition of which of the following improves
machining of copper?
(a) Sulphur
(b) Vanadium
(c) Tin
(d) Zinc

15. IES-2006
Disruptive strength is the maximum strength of a
metal, when
(a) Subjected to 3 principal tensile stresses at right
angles to one another and of equal magnitude
(b) Loaded in tension
(c) Loaded in compression
(d) Loaded in shear

16. IAS-1996
Match List I with List II and select the correct answer
using the codes given below the lists:
List I (Cutting tools) List II (Major constituent)
A. Stellite l. Tungsten
B. H.S.S. 2. Cobalt
C. Ceramic 3. Alumina
D. DCON 4. Columbium
5. Titanium
Codes: A B C D A B C D
(a) 5 1 3 4 (b) 2 1 4 3
(c) 2 1 3 4 (d) 2 5 3 4

17. IAS-1998
Which of the following methods are suitable for
the production of super alloys?
1. Atomization from molten state using inert gas.
2. Atomization using plasma arc and rotating
electrode.
3. Reduction and crushing.
Select the correct answer using the codes given below:
Codes:
(a) 1 and 2 (b) 2 and 3
(c) 1 and 3 (d) 1, 2 and 3

18. IES-1996
The limit to the maximum hardness of a work
material which can be machined with HSS tools
even at low speeds is set by which one of the
following tool failure mechanisms?
(a) Attrition
(b) Abrasion
(c) Diffusion
(d) Plastic deformation under compression.

19. GATE-2002
The ductility of a material with work hardening
(a) Increases (b) Decreases
(c) Remains unaffected (d) Unpredictable

20. IES-2009
Nano composite materials are highly preferable in
design consideration for their
(a) High resistance to crack propagation
(b) Vibration resistance
(c) Impact resistance
(d) High resilience

21. IES-1992
Machine tool frame should have
(a) High rigidity to weight ratio
(b) Graphite in the form of nodules
(c) Low hardness
(d) High work hardness

22. GATE-1995
Machine tool structures are made …………..for high
process capability. (tough/strong/rigid)

23. IES-2009
Which one of the following possesses the property
of nonsparking character?
(a) Hadfield's manganese steel (b) Spring steel
(c) Stellite (d) Invar

24. JWM 2010
Consider the following properties of engineering
materials
1. Density
2. Conductivity
3. Elasticity
4. Hardness
5. Ductility
Which of these are mechanical properties of a
material ?
(a) 1, 2 and 4 only (b) 1, 2, 3 and 4
(c) 3, 4 and 5 (d) 2, 4 and 5

25. IES 2011
Materials which show direction dependent properties are
called:
(a) Homogeneous
(b) Visco-elastic
(c) Isotropic
(d) Anisotropic

26. IES 2011
Lead is widely used in:
(a) Transformers
(b) Switch gear
(c) Galvanized pipes
(d) Batteries

27. IES 2011
Match List –I with List –II and select the correct answer using
the code given below the lists :
Codes
A B C D A B C D
(a) 2 1 4 3 (b) 3 1 4 2
(c) 2 4 1 3 (d) 3 4 1 2
List –I List –II
A. System 1. Free energy is a minimum
B. Phase 2. Chemical elements or chemical
compounds
C. Phase
equilibrium
3. Consists of solids, liquids or gasses or their
combination
D. Components 4. Homogeneous portion of a system that
has uniform physical characteristics

28. GATE-2005
When the temperature of a solid metal increases
(a) Strength of the metal decreases but ductility
increases
(b) Both strength and ductility of the metal decrease
(c) Both strength and ductility of the metal increase
(d) Strength of the metal increases but ductility
decreases

29. IAS-1998
Magnesium is extruded and not rolled because
(a) It has a low melting point
(b) It has a low density
(c) Its reactivity with roll material is high
(d) It has a dose-packed hexagonal structure

30. IES 2011
Match List –I with List –II and select the correct answer using
the code given below the lists :
Codes
A B C D A B C D
(a) 1 2 3 4 (b) 4 2 3 1
(c) 1 3 2 4 (d) 4 3 2 1
List –I List –II
A. Elasticity 1. Deform non elastically without fracture
B. Malleability 2. Undergo plastic deformation under tensile
load
C. Ductility 3. Undergo plastic deformation under
compressive load
D. Plasticity 4. Return to its original shape on unloading

31. IES 2011
Injection moulding process used to produce
thermoplastic matrix composites with fibre
reinforcement normally gives:
(a) Short fibre composites
(b) Two layer structure composites
(c) Continuous fibre composites
(d) Single layer composites

32. IES 2011
Assertion (A) : Solid solutions of metal are
crystal whose properties are close to those of
the solvent.
Reason (R) : They retain the same crystal lattice
and type of bond.
(a) Both A and R are individually true and R is the
correct explanation of A
(b) Both A and R are individually true but R is NOT
the correct explanation of A
(c) A is true but R is false
(d) A is false but R is true

33. IES 2010
The correct statement is
(a) Characteristic of any series of alloys cannot be
found by phase diagram.
(b) Phase diagram does not give amount of
phases which are a function of composition,
temperature and pressure.
(c) The phase may be liquid or vapour with
ordered crystal structure.
(d) Phase diagram provides the information on
how rapidly equilibrium is reached.

34. JWM 2010
Assertion (A) : Electric arc furnace can be used for
acid and basic method of steel making.
Reason (R) : Impurities are eliminated extensively
in acid are process.

35. IES 2010
Consider the following:
1. Water
2. Ice
3. Brine solution
4. Oil
Which of these is/are used as quenching
media in case of Alloy steels?
(a) 1, 2 and 3 only (b) 2, 3 and 4 only
(c) 1 and 4 only (d) Only

36. The End