1. Maximum water percentage in refractory mix meant foe hand moulding may be as high as …………percent.
(A) 2 – 3
(B) 5 – 7
(C) 7 – 12
(D) 14 – 20 ✔
2. Mashine moulding of dry mixture of refractories require a pressure of the order of ………….. kg / cm²
(A) 10
(B) 100
(C) 500
(D) 1000 ✔
3. Faster rate of drying of moulded refractories results in high ………of refractories
(A) Green strength
(B) Voids
(C) Shrinkage
(D) Both [B] and [C] ✔
4. An allotropic material has
(A) Same crystal structure at all temperature
(B) Different crystal structure at different temperature ✔
(C) Randomly distributed atoms
(D) None of the above
5. Which of the following is not used as the ceramic material in “carmets”?
(A) Silicides
(B) Oxides
(C) Carbides
(D) Nitrides ✔
6. Carbide ceramics in carmets are not bonded by ?
(A) Cu ✔
(B) Ni
(C) Co
(D) Fe
7. Ceramic materials fabrication can not be done by
(A) Welding ✔
(B) Slip casting
(C) Extrusion
(D) Plastic pressing
8. Glass lined vessels are not used for handling
(A) Dilute Sulphuric acid
(B) Dilute Nitric acid
(C) Dilute hydrochloric acid
(D) Hydroflouric acid ✔
9. Which is the best moulding process for production of large intricate casting weighing > 100 tons?
(A) Pit moulding ✔
(B) Ceramic moulding
(C) Green sand moulding
(D) Cement moulding
10. What is the melting point( ?C ) of pure silica sand = 99.8 %
(A) 750
(B) 950
(C) 1150 ✔
(D) 1450
11. Mould made of …..… is used in centrifugal casting
(A) Plaster of paris
(B) Metal ✔
(C) Wax
(D) Frozen mercury
12. ……………. is used for making chaplets
(A) Plaster of paris
(B) Metal ✔
(C) Wax
(D) Frozen mercury
13. …………. of sand is found by shatter test
(A) Toughness ✔
(B) Gain fineness number
(C) Sintering temperature
(D) None of the above
14. Mould wash is used to ………of the moulds
(A) Increase the hot strength
(B) Increase the green compressive strength ✔
(C) Decreases the permeability
(D) None of the above
15. Moulding sand comprises of sand , moisture and
(A) Sea coal ✔
(B) Clay
(C) Exothermic powder
(D) None of the above
16. Which of the following has the least Carbon percentage ?
(A) Low carbon steel
(B) Mild steel
(C) Wrought iron ✔
(D) White cast iron
17. The purpose of nitriding the steel is to
(A) Harden its surface ✔
(B) Soften its surface
(C) Improve its rollability
(D) None of the above
18. Carbon percentage is same in the cast iron and
(A) Low carbon steel
(B) Mild steel
(C) Pig iron ✔
(D) White cast iron
19. The presence of impurities in iron
(A) Increases its melting point
(B) Decreases its melting point ✔
(C) All of the above
(D) None of the above
20. Which has the maximum melting point of the following ?
(A) Steel
(B) Wrought iron ✔
(C) Stainless steel
(D) Cast iron
21. In ……. Materials , atoms are arranged regularly in some direction but not in others
(A) Metamorphous ✔
(B) Amorphous
(C) Crystalline
(D) None of the above
22. Which is an Amorphous material ?
(A) Glass ✔
(B) Mica
(C) Brass
(D) None of the above
23. Atoms are arranged chaotically in …………materials
(A) Metamorphous
(B) Amorphous ✔
(C) Crystalline
(D) None of the above
24. An example of Metamorphous material is ?
(A) Lead
(B) Cast iron
(C) Mica ✔
(D) None of the above
25. Microstructure of a material is usually examined by the
(A) Metallurgical microscope ✔
(B) Optical microscope
(C) All of the above
(D) None of the above
26. Crystal structure of a material is usually examined by
(A) X – Ray technique ✔
(B) Metallurgical microscope
(C) Optical microscope
(D) None of the above
27. A hardened steel usually contains
(A) Austenite
(B) Marten site ✔
(C) Pearlite
(D) Sorbite
28. Casting are usually subjected to ……… heat treatment process
(A) Tampering
(B) Normalizing ✔
(C) Carburizing
(D) Annealing
29. Hardened steel is softened by
(A) Tampering
(B) Normalizing ✔
(C) Carburizing
(D) Annealing
30. Addition of nickel to copper improves its
(A) Machinability
(B) Ductility
(C) Strength
(D) Hardness ✔
31. Addition of silicon to copper improves its
(A) Machinability
(B) Ductility
(C) Strength
(D) Hardness and strength ✔
32. A steel containing both cementite and pearlite is
(A) Tough
(B) Soft
(C) Hard ✔
(D) Hard and tough
33. Hardness of martensite is about RC
(A) 24
(B) 50
(C) 65 ✔
(D) 95
34. Addition of copper improves its
(A) Machinability
(B) Ductility and strength ✔
(C) Strength
(D) Hardness and strength
35. White cast iron is produced by the ………of
(A) Slow heating
(B) Rapid heating ✔
(C) Slow cooling
(D) rapid cooling
36. Steel produce from phosphatic iron is
(A) Tough
(B) Hard
(C) Brittle ✔
(D) Soft
37. Which of the following if present in steel increases its hardness?
(A) Martensite ✔
(B) Austenite
(C) Pearlite
(D) Cementite
38. Inver contains highest percentage of
(A) Vanadium
(B) Iron ✔
(C) Tungsten
(D) Cobalt
39. The steel containing ferrite and pearlite is
(A) Tough
(B) Very hard
(C) Soft ✔
(D) None of the above
40. Which of the following is present in hard steel ?
(A) Martensite ✔
(B) Austenite
(C) Pearlite
(D) Cementite
41. A ferromagnetic substances at curie temperature changes to
(A) Paramagnetic ✔
(B) Diamagnetic
(C) Insulator
(D) None of the above
42. Line defects in crystals play vital role in
(A) Conductance
(B) Deformation ✔
(C) Dislocation
(D) None of the4 above
43. …………….materials tend to obey Curie Law
(A) Metallic
(B) Non-metallic
(C) Diamagnetic ✔
(D) Paramagnetic
44. Ceramic recuperators used for the waste heat recovery from high temperature flue gas going out of the furnace is made of
(A) Fireclay
(B) Silicon carbide ✔
(C) Corrundum
(D) Siliceous fireclay
45. Carmets are combination of ceramic and metallic material due to which they have high strength and resistance to high temperature. Carmets ate used in the
(A) Hearth of the blast furnace
(B) Nuclear reactors, missiles and space crafts ✔
(C) Insulation of high temperature furnaces
(D) Roof of electric furnace
46. Spalling of a refractory means it
(A) Softening
(B) Fracture due to uneven expansion at high temperature ✔
(C) Resistance to compressive loads
(D) None of the above
47. An ideal refractory should have
(A) High spalling rate
(B) High fusion point ✔
(C) Shrinkage ability
(D) None of the above
48. The largest annual consumer of refractories is the ……….industry
(A) Cement
(B) Metallurgical
(C) Fertilizer
(D) Power ✔
49. Refractory materials are never used in the construction of
(A) Sugar cones
(B) Orton cones
(C) Pressure vessels ✔
(D) Ovens and retorts
50. Which of the following is not an acidic refractory
(A) Zorconia
(B) Silicon carbide ✔
(C) Magnesia
(D) None of the above
51. Ferromagnetic ceramic material is used in the
(A)Thermal insulation ✔
(B) Transformer
(C) Magnetic switches
(D) Television sets
52. Spalling resistance of a refractory can not be increased by
(A) Increasing its porosity
(B) Using a coarser grog during its manufacture
(C) Making it denser ✔
(D) None of the above
53. Which of the following is not an acidic refractory
(A) Silica bricks
(B) Fireclay bricks
(C) Magnesia bricks ✔
(D) Bauxite bricks
54. Electrical resistors bars are made of
(A) Silicon carbide ✔
(B) Alumunia
(C) Zirconica
(D) Graphite
55. ………..nozzles are used in the continous casting of steel
(A) Zircon ✔
(B) Thoria
(C) Carborundum
(D) Beryllia
56. Cold crushing strength of a refractory does not depend upon its
(A) Shape ✔
(B) Composition
(C) Firing temperature
(D) Texture
57. High thermal conductivity of a refractory material is nit important when it is to be used in the
(A) Coke oven regenerators
(B) Muffle furnace
(C) Blast furnace ✔
(D) Recuperators
58. Magnesite refractories are not used in the lining of
(A) Electric furnace walls
(B) Steel melting furnace ✔
(C) Open hearth furnace
(D) Burning zone of cement kilns
59. …………of carbon blocks in the hearth of blast furnace helps in avoiding skull formation when it becomes cold
(A) High thermal conductivity
(B) Low porosity
(C) Non – wetting characteristics ✔
(D) High density
60. Which of the following is not a neutral refractory ?
(A) Silicon carbide
(B) Magnesite ✔
(C) Chromite
(D) Graphite
61. Graphite of carbon refractories n
(A) Exibits wetting characteristics
(B) Should be used in neutral or reducing atmosphere ✔
(C) All of the above
(D) None of the above
62. Thermal spalling mainly occurs during ………..of furnace
(A) Cooling down
(B) Warming up
(C) All of the above ✔
(D) None of the above
63. Spalling tendency of refractories is reduced by increasing its
(A) Porosoty ✔
(B) Specific gravity
(C) Thermal conductivity
(D) Strength
64. Except ……….. all other factories are bad conductors of electricity
(i. e low electrical conductivity )
(A) Fireclay
(B) Carbotundum
(C) Graphite ✔
(D) Chromite
65. Glass is corroded by
(A) Fluorine(dry or wet ) ✔
(B) Sulphuric acid
(C) Phosphoric acid
(D) None of the above
66. Ceramic recuperators are generally made of
(A) Silicon carbide ✔
(B) Calcium carbide
(C) Fireloay bricks
(D) High aluminia bricks
67. Carbon percentage is same in cast iron and
(A) Wrought iron
(B) Pig iron ✔
(C) Mild steel
(D) High silicon
68. Maximum shrinkage of volume occurring during burning / firing of dried refractories May be as high as ………………percent
(A) 10
(B) 15
(C) 20
(D) 30 ✔
69. Which of the following does not occur during burning / firing of refractories?
(A) Removal of water of hydration
(B) Vetrification
(C) Decreasing in the crushing strength ✔
(D) Development of stable mineral form
70. Which is not a high alumina refractory ?
(A) Mullite
(B) Corrundum
(C) Baxuite
(D) Dolomite ✔