Engineering Materials

91. Large forgings, crank shafts, axles normally contain carbon up to

1. 0.05 to 0.20%
2. 0.20 to 0.45%
3. 0.45 to 0.55%
4. 0.55 to 1.0%
5. 1.0 to 1.2%.

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92. Lead is poured into the joint between two pipes. These pipes may be made of

1. cast iron
2. vitrified clay
3. asbestos cement
4. concrete
5. mild steel.

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93. Machining properties of steel are improved by adding

1. sulphur, lead, phosphorous
2. silicon, aluminium, titanium
3. vanadium, aluminium
4. chromium, nickel
5. lubricants.

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94. Malleability of a material can be defined as

1. ability to undergo large permanent deformations in compression
2. ability to recover its original form
3. ability to undergo large permanent deformations in tension
4. all of the above
5. none of the above.

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95. Malleable cast iron

1. contains l.7 to 3.5% carbon in free state and is obtained by the slow cooling of molten cast iron
2. is also known as chilled cast iron and is obtained by cooling rapidly. It is almost unmachinable
3. is produced by annealing process. It is soft, tough, and easily machined metal
4. is produced by small additions of magnesium (or cerium) in the ladle. Graphite is in the nodular or spheroidal form and is well dispersed throughout the material
5. none of the above.

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96. Manganese in steel increases its

1. tensile strength
2. hardness
3. ductility
4. fluidity
5. malleability.

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97. Materials after cold working are subjected to following process to relieve stresses

1. hot working
2. tempering
3. normalising
4. annealing
5. special heat treatment.

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98. Maximum percentage of carbon in austenite is

1. 0.025%
2. 0.26%
3. 0.8%
4. 1.25%
5. 1.7%.

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99. Maximum percentage of carbon in ferrite is

1. 0.025%
2. 0.06%
3. 0.1%
4. 0.25%
5. 0.8%.

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100. Melting point of iron is

1. 1539°C
2. 1601°C
3. 1489°C
4. 1712°C
5. 1131°C.

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