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MCQ
662. Following elements have face-centred cubic structure—
gamma iron (910° to 1400°C), Cu, Ag, Au, Al, Ni, Pb, Pt
Mg, Zn. Ti. Zr, Br, Cd
a iron (below 910°C and between1400 10 1539°C), W
all of the above
668. Grey cast iron--
contains 1.7 to 3.5% carbon in free state and is obtained by the slow cooling of molten
is also known as chilled cast iron and is obtained by cooling rapidly. It is almost non-machinable
is produced by annealing process. It is soft, tough and easily machine metal
is produced by small additions of magnesium (or cerium) in the ladle. Graphite is in nodular or spheroida form and is well dispersed throughout the material
671. The correct composition of Babbit metal is—
87.75% Sn, 4% Cu, 8% Sb. 0.25% Bi
90% Sn, 2% Cu, 4% Sb. 2% Bi, 2% Mg
87% Sn, 4% Cu, 8% Sb, 1% Al
82% Sn, 4% Cu, 8% Sb, 3% Al. 35% Mg
673. Nickel in steel—
improves wear resistance, cuttinability and toughness
refines grain size and produces les tendency to carburisation, improve corrosion and heat resistant proper ties
improves cutting ability and reduce hardenability
gives ductility, toughness, tensile strength and anti-corrosion property
674. Duralumin contains—
94% aluminium, 4% copper and 0.5% Mn. Mg. Si and Fe
10% aluminiunt and 90% copper
90% magnesium and alumunium with some copper
92.5% aluminium, 40% copper, 2%, nickel, and 1.5% Mg
675. Ductile cast iron—
contains 1.7 to 3.5% carbon in free state and is obtained by the slow cooling of molten cast iron
is also known as chilled cast iron and is obtained by cooling rapidly. It is almost non-machinable
is produced by annealing process. It is soft, tough and easily machined metal
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
680. Cobalt in steel—
improves wear resistance, cuttinability and toughness
refines grain size and produces les tendency to carburisation, improve corrosion and heat resistant proper ties
improves cutting ability and reduce hardenability
gives ductility, toughness, tensile strength and anti-corrosion property