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Material Science

Material Science
Question:-
Option (A)

18% stainless, 8% chromium

Option (B)

18% chromium, 8% nickel

Option (C)

18% tungsten, 8% nickel

Option (D)

18% tungsten, 8% chromium

Correct Option:
B
Question Solution:

18/8 signifies 18% Chromium and 8% nickel it is also called austenitic stainless steel non magnetic in nature, Titanium niobium added to stabilize the carbon

Question:-
Option (A)
Hardness
Option (B)
Ductility and strength in tension
Option (C)
Corrosion resistance
Option (D)
Creep strength
Correct Option:
B
Question:-
Option (A)
600°C
Option (B)
723°C
Option (C)
114°C
Option (D)
1493°
Correct Option:
B
Question Solution:
Eutectoid reaction is at 0.76% of carbon at 727°C in iron carbon diagram in which austenite transforms to pea rite. (% of carbon)
Question:-
Option (A)
Weldability
Option (B)
Formability
Option (C)
Machinability
Option (D)
Hardenability
Correct Option:
C
Question Solution:
Sculpture from MnS when manganese is added which increases mach inability. Its amount is controlled because formation of GeS leads to hot shortness as FeS is low melting
Question:-
Option (A)
A B C D
4 3 2 1

Option (B)
A B C D
1 3 4 2

Option (C)
A B C D
4 1 2 3

Option (D)
A B C D
1 2 3 4

Correct Option:
A
Question Solution:
Hypoeutectoid steel 0.008 - 0.76
Hypereutectoid steel 0.76 - 2.1
Hypoeutectic steel 2.1 – 4.3
Hypereutectic steel 4.3- 6.64
Question:-
Option (A)
A B C D
4 3 2 1

Option (B)
A B C D
1 3 4 2
Option (C)
A B C D
4 2 1 3

Option (D)
A B C D
2 1 3 4

Correct Option:
A
Question Solution:
Annealing is softening process which improves ductility. Normalizing is cooling of material in air so it refines grain structures (due to faster cooling than annealing) Nit riding is employed with alloy steel in which different alloys forms their respective nitrides so surface hardness improves
Mar tempering is two stage cooling process avoiding the nose of TTT diagram to from marten site. The two stage cooling minimizes distortion and quench crack