RRB Group D - Engineering Materials 1000+ MCQ [Solved] PDF Download

1. Pearlite consists of
A. 13% carbon and 87% ferrite
B. 13% cementite and 87% ferrite
C. 13% ferrite and 87% cementite
D. 6.67% carbon and 93.33% iron
Answer : B

2. In malleable iron, carbon is present in the form of
A. Cementite
B. Free carbon
C. Flakes
D. Nodular aggregates of graphite
Answer : D

3. Cyaniding is the process of
A. Dipping steel in cyanide bath
B. Reacting steel surface with cyanide salts
C. Adding carbon and nitrogen by heat treatment of steel to increase its surface hardness
D. Obtaining cyanide salts
Answer : C

4. Carbon steel is
A. Made by adding carbon in steel
B. Refined from cast iron
C. An alloy of iron and carbon with varying quantities of phosphorus and sulphur
D. Extensively used for making cutting tools
Answer : C

5. A reversible change in the atomic structure of steel with corresponding change in the properties is known as
A. Molecular change
B. Physical change
C. Allotropic change
D. Solidus change
Answer : C

6. An important property of malleable cast iron in comparison to grey cast iron is the high
A. Compressive strength
B. Ductility
C. Carbon content
D. Hardness
Answer : B

7. The following types of materials are usually the most ductile
A. Face centred cubic lattice
B. Body centred cubic lattice
C. Hexagonal close packed lattice
D. All of the above
Answer : A

8. Beryllium bronze contains
A. 60% copper and 40% beryllium
B. 80% copper and 20% beryllium
C. 97.75% copper and 2.25% beryllium
D. 99% copper and 1% beryllium
Answer : C

9. Crystal structure of a material is, generally, examined by
A. Naked eye
B. Optical microscope
C. Metallurgical microscope
D. X-ray techniques
Answer : D

10. The alloy used for making electrical resistances and heating elements is
A. Nichrome
B. Invar
C. Magnin
D. Elinvar
Answer : A

11. Grey cast iron has
A. Carbon in the form of free graphite
B. High tensile strength
C. Low compressive strength
D. All of these
Answer : A

12. Brass is an alloy of
A. Copper and zinc
B. Copper and tin
C. Copper, tin and zinc
D. None of these
Answer : A

13. In process annealing, the hypo eutectoid steel is
A. Heated from 30°C to 50°C above the upper critical temperature and then cooled in still air
B. Heated from 30°C to 50°C above the upper critical temperature and then cooled suddenly in a suitable cooling medium
C. Heated from 30°C to 50°C above the upper critical temperature and then cooled slowly in the furnace
D. Heated below or closes to the lower critical temperature and then cooled slowly
Answer : D

14. By severely deforming a metal in a particular direction it becomes
A. Ductile
B. Malleable
C. Homogeneous
D. Anisotropic
Answer : D

15. Aluminium bronze contains aluminium and copper in the ratio of
A. 50 : 50
B. 40 : 60
C. 60 : 40
D. 10 : 90
Answer : D

16. Melting point of iron is
A. 1539°C
B. 1601°C
C. 1489°C
D. 1712°C
Answer : A

17. Thermoplastic materials are those materials which
A. Are formed into shape under heat and pressure and results in a permanently hard product
B. Do not become hard with the application of heat and pressure and no chemical change occurs
C. Are flexible and can withstand considerable wear under suitable conditions
D. Are used as a friction lining for clutches and brakes
Answer : B

18. Which of the following constituents of steels is softest and least strong?
A. Austenite
B. Pearlite
C. Ferrite
D. Cementite
Answer : C

19. Mild steel belongs to the following category
A. Low carbon steel
B. Medium carbon steel
C. High carbon steel
D. Alloy steel
Answer : A

20. White cast iron
A. Contains 1.7 to 3.5% carbon in Free State and is obtained by the slow cooling of molten cast iron
B. Is also known as chilled cast iron and is obtained by cooling rapidly. It is almost unmachinable
C. Is produced by annealing process. It is soft, tough and easily machined metal
D. Is produced by small additions of magnesium (or creium) in the ladle. Graphite is in nodular or spheroidal form and is well dispersed throughout the material
Answer : B

21. The heat treatment process used for softening hardened steel is
A. Carburising
B. Normalising
C. Annealing
D. Tempering
Answer : D

22. Amorphous material is one
A. In which atoms align themselves in a geometric pattern upon solidification
B. In which there is no definite atomic structure and atoms exist in a random pattern just as in a liquid
C. Which is not attacked by phosphorous
D. Which emits fumes on melting
Answer : B

23. Babbitt metal is a
A. Lead base alloy
B. Copper base alloy
C. Tin base alloy
D. Cadmium base alloy
Answer : C

24. Large forgings, crank shafts, axles normally contain carbon up to
A. 0.05 to 0.20 %
B. 0.20 to 0.45 %
C. 0.45 to 0.55 %
D. 0.55 to 1.0 %
Answer : C

25. The lower critical temperature
A. Decreases as the carbon content in steel increases
B. Increases as the carbon content in steel increases
C. Is same for all steels
D. Depends upon the rate of heating
Answer : C

26. In high speed steels, manganese is used to tougher the metal and to increase its
A. Yield point
B. Critical temperature
C. Melting point
D. Hardness
Answer : B

27. When medium carbon steel is heated to coarsening temperature
A. There is no change in grain size
B. The average grain size is a minimum
C. The grain size increases very rapidly
D. The grain size first increases and then decreases very rapidly
Answer : C

28. Inconel is an alloy of
A. Nickel, chromium and iron
B. Nickel, copper
C. Nickel, Chromium
D. Nickel, zinc
Answer : A

29. The portion of the blast furnace below its widest cross-section is called
A. Hearth
B. Stack
C. Bosh
D. Throat
Answer : C

30. The most effective inhibitor of grain growth, when added in small quantities is
A. Carbon
B. Vanadium
C. Manganese
D. Cobalt
Answer : B

31. Alnico, an alloy used extensively for permanent magnets contains iron, nickel, aluminium and cobalt in the following ratio
A. 50 : 20 : 20 : 10
B. 40 : 30 : 20 : 10
C. 50 : 20 : 10 : 20
D. 30 : 20 : 30 : 20
Answer : A

32. Blast furnace produces following by reduction of iron ore
A. Cast iron
B. Pig iron
C. Wrought iron
D. Malleable iron
Answer : B

33. When filing or machining cast iron makes our hands black, then it shows that ________ is present in cast iron.
A. Cementite
B. Free graphite
C. Both A and B
D. None of these
Answer : B

34. The maximum internal diameter of a blast furnace is about
A. 3 m
B. 6 m
C. 9 m
D. 12 m
Answer : C

35. Sulphur in pig iron tends to make it
A. Hard
B. Soft
C. Ductile
D. Tough
Answer : A

36. Chilled cast iron has
A. No graphite
B. A very high percentage of graphite
C. A low percentage of graphite
D. Graphite as its basic constituent of composition
Answer : A

37. Drop forging dies contain carbon of the order of
A. 0.1 to 0.2 %
B. 0.25 to 0.5 %
C. 0.6 to 0.7 %
D. 0.7 to 0.9 %
Answer : C

38. The coke in the charge of blast furnace
A. Controls the grade of pig iron
B. Acts as an iron bearing mineral
C. Supplies heat to reduce ore and melt the iron
D. Forms a slag by combining with impurities
Answer : C

39. Sulphur in steel
A. Acts as deoxidiser
B. Reduces the grain size
C. Decreases tensile strength and hardness
D. Lowers the toughness and transverse ductility
Answer : D

40. Maximum percentage of carbon in ferrite is
A. 0.025 %
B. 0.06 %
C. 0.1 %
D. 0.25 %
Answer : A

41. Delta metal is an alloy of
A. Copper, zinc and iron
B. Iron, nickel and copper
C. Iron, lead and tin
D. Iron, aluminium and magnesium
Answer : A

42. Which of the following is added in low carbon steels to prevent them from becoming porous?
A. Sulphur
B. Phosphorus
C. Manganese
D. Silicon
Answer : D

43. When low carbon steel is heated up to upper critical temperature
A. There is no change in grain size
B. The average grain size is a minimum
C. The grain size increases very rapidly
D. The grain size first increases and then decreases very rapidly
Answer : B

44. Tungsten in steel
A. Improves wear resistance, cutting ability and toughness
B. Refines grain size and produces less tendency to carburisation, improves corrosion and heat resistant properties
C. Improves cutting ability and reduces hardenability
D. Gives ductility, toughness, tensile strength and anticorrosion properties
Answer : B

45. Admiralty gun metal contains
A. 63 to 67% nickel and 30% copper
B. 88% copper, 10% tin and rest zinc
C. Alloy of tin, lead and cadmium
D. Iron scrap and zinc
Answer : B