101. Sulphur in steel
(a) acts as deoxidiser
(b) reduces the grain size
(c) decreases tensile strength and hard-ness
(d) lowers the toughness and transverse ductility
(e) increases hardness.
Ans: d
102. 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
(e) raises its melting point.
Ans: b
103. Tungsten in high speed steel provides
(a) hot hardness
(b) toughness
(c) wear resistance
(d) sharp cutting edge
(e) cold hardness.
Ans: a
104. Which of the following is not the correct method of increasing fatigue limit
(a) shot peening
(b) nitriding of surface
(c) cold working
(d) surface decarburisation
(e) under-stressing.
Ans: d
105. Connecting rod is usually made of
(a) aluminium
(b) low carbon steel
(c) medium carbon steel
(d) high carbon steel
(e) cast iron.
Ans: c
106. Which of lh6 following pipes is least corrosion resistant
(a) brass
(b) mild steel
(c) cast iron
(d) wrought iron
(e) copper.
Ans: d
107. Tensile strength of steel can be safely increased by
(a) adding carbon upto 2.8%
(b) adding carbon upto 6.3%
(c) adding carbon upto 0.83%
(d) adding small quantities of copper
(e) adding copper and carbon.
Ans: c
108. High carbon steel carries carbon %age c
(a) 0.1 to 0.3%
(b) 0.3 to 0.6%
(c) 0.6 to 0.8%
(d) 0.8 to 1.5%
(e) 1.5 to 2.5%.
Ans: d
109. Cobalt in steel
(a) improves wear resistance, cuttin ability and toughness
(b) refines grain size and produces les tendency to caricaturisation, improve corrosion and heat resistant proper ties
(c) improves cutting ability and reduce harden ability
(d) gives ductility, toughness, tensil strength and anti corrosion properties:
(e) none of the above.
Ans: c
110. The percentage of carbon in low carbon steel is
(a) 0.05%
(b) 0.15%
(c) 0.3%
(d) 0.5%
(e) 0.7%.
Ans: b
111. The hardness of steel increases if it contains
(a) austenite
(b) martensite
(c) pearlite
(d) cementite
(e) all of the above.
Ans: b
112. Grey cast iron
(a) contains 1.7 to 3.5% carbon in fre< state and is obtained by the slov cooling of molten cast iron
(b) is also known as chilled cast iron am is obtained by cooling rapidly. It i: almost unmachinable
(c) is produced by annealing process. I is soft, tough and easily machinec metal
(d) is produced by small additions o magnesium (or cerium) in the ladle Graphite is in nodular or spheroida form and is well dispersed throughou the material
(e) none of the above is true.
Ans: a
113. Nodular iron has
(a) high maehinability
(b) low melting point
(c) high tensile strength
(d) good fluidity
(e) all of the above.
Ans: e
114. Nickel 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
(e) none of the above.
Ans: d
115. Which of the following elements does not impart hardness to steel
(a) copper
(b) chromium
(c) nickel
(d) silicon
(e) none of the above.
Ans: a
116. The presence of sulphur in pig iron makes
(a) it easily machinable
(b) it brittle
(c) it hard
(d) the casting unsound
(e) increases the fluidity.
Ans: d
117. Melting point of iron is
(a) 1539°C
(b) 1601°C
(c) 1489°C
(d) 1712°C
(e) 1131°C.
Ans: a
118. Compressive strength of grey cast iron in tonnes/cm is of the order of
(a) 3- 5
(b) 5-7
(c) 7-10
(d) 10-15
(e) 15-22.
Ans: b
119. Blast furnace produces following by reduction of iron ore
(a) cast iron
(b) pig iron
(c) wrought iron
(d) malleable iron
(e) white iron.
Ans: b
120. Cupola produces following material
a) cast iron
(b) pig iron
(C) wrought iron
(d) malleable iron
(e) white iron.
Ans: a
121. The machinability of steel is increased by
(a) silicon and sulphur
(b) phosphorous, lead and sulphur
(c) sulphur, graphite and aluminium
(d) phosphorous and aluminium
(e) none of the above.
Ans: b
122. The following element can’t impart high strength at elevated temperature
(a) manganese
(b) magnesium
(c) nickel
(d) silicon
(e) none of the above.
Ans: b
123. Which of the following element results in presence of free graphite in C.I.
(a) carbon
(b) sulphur
(c) silicon
(d) manganese
(e) phosphorous.
Ans: c
124. 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
(e) none of the above.
Ans: b
125. Cold rolled steel sheets contain carbon of the following order
(a) 0.1%
(b) 0.2%
(c) 0.4%
(d) 0.6%
(e) 0.8%.
Ans: a