1) Malleability of a material can be defined as ______________________? a. ability to undergo large permanent deformations in compression b. ability to recover its original form c. ability to undergo large permanent deformations in tension d. all of the above e. none of the above
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2) Mild steel belongs to the following category___________________? a. low carbon steel b. medium carbon steel c. high carbon steel d. alloy steel e. special steel
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3) Stress relaxation is- the phenomenon ___________________? a. in which parts are not loaded b. in which stress remains constant on in-creasing load c. in which deformation tends to loosen the joint and produces a stress reduced d. stress reduces on increasing load e. none of the above
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4) Isotropic materials are those which have the same ____________________? a. elastic properties in all directions b. stresses induced in all directions c. thermal properties in all directions d. electric and magnetic properties in all directions e. density throughout
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5) The ability of a material to resist softening at high temperature is known as____________________? a. creep b. hot tempering c. hot hardness d. fatigue e. superhardening
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6) The ultimate tensile strength and yield strength of most of the metals, when temperature falls from 0 to l00°C will _________________? a. increase b. decrease c. remain same d. first increase and then decrease e. show unpredictable behaviour
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7) Points of arrest for iron correspond to__________________? a. stages at which allotropic forms change b. stages at which further heating does not increase temperature for some time c. stages at which properties do not change with increase in temperature d. there is nothing like points of arrest e. none of the above
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8) A material is known as allotropic or polymorphic if it __________________? a. has a fixed structure under all conditions b. exists in several crystal forms at different temperatures c. responds to heat treatment d. has its atoms distributed in a random pattern e. none of the above
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9) Which of the following constituents of steels is softest and least strong ________________? a. austenite b. pearlite c. ferrite d. cementlte e. bainite
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10) The temperature at which ferromagnetic alpha iron transforms to paramagnetic alpha iron is _______________? a. 770°C b. 910°C c. 1050°C d. below recrystallisation temperature e. above recrystallization temperature
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11) Ferromagnetic alpha iron exists in temperature range of________________? a. below 723°C b. 770 – 910°C c. 910-1440°C d. 1400-1539°C e. above 1539°C
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12) 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 e. atomic change
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13) The crystal of alpha iron is ____________________? a. body centred cubic b. face centred cubic c. hexagonal close packed d. cubic structure e. orthorhombic crystal
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14) For the allotropic forms of iron, the points of arrest are __________________? a. the points where no further change oc-curs b. constant for all metals c. the points where there is no further flow of metal d. the points of discontinuity e. the points where major changes take place
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15) The percentage of carbon in grey iron castings usually varies between __________________? a. 0.5 to 1% b. 1 – 2% c. 2.5 to 4.5% d. 5 – 7% e. 7-9%.
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16) The unique property of cast iron is its high ___________________? a. malleability b. ductility c. surface finish d. damping characteristics e. hardness
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17) In grey cast iron, carbon is present in the form of____________________? a. cementite b. free carbon c. flakes d. spheroids e. nodular aggregates of graphite
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18) In malleable iron, carbon is present in the form of___________________? a. cementite b. free carbon c. flakes d. spheroids e. nodular aggregates of graphite
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19) 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 e. none of the above
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20) Sulphur in pig iron tends to make it___________________? a. hard b. soft c. ductile d. tough e. malleable
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