In grey cast iron, carbon is present in the form of____________________?

A. Cementite
B. Free carbon
C. Flakes
D. Spheroids

The unique property of cast iron is its high ___________________?

A. Malleability
B. Ductility
C. Surface finish
D. Damping characteristics

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%

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

The crystal of alpha iron is ____________________?

A. Body centred cubic
B. Face centred cubic
C. Hexagonal close packed
D. Cubic structure

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

Ferromagnetic alpha iron exists in temperature range of________________?

A. Below 723°c
B. 770 – 910°c
C. 910-1440°c
D. 1400-1539°c

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

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

Which of the following constituents of steels is softest and least strong ________________?

A. Austenite
B. Pearlite
C. Ferrite
D. Cementlte