267. Hyperecutetoid steels have structure of
A.Pearlite alone
B.Phases of ferrite and pearlite
C.Phases of cementite and pearlite
D.Phases of ferrite and cementite
268. The temperature and carbon content at which eutectic reaction occurs in Fe-C equilibrium diagram are
A.723°C and 0.02%C
B.723°C and 0.80%C
C.910°C and 4.30%C
D.1130°C and 2.00%C
269. The temperature at which new grains are formed in a metal is called
A.Recrystallisation temprature
B.Lower critical temperature
C.Upper critical temperature
D.Eutectitc temperature
270. The temperature and carbon content at which eutectoid reaction occurs in Fe-C equilibrium diagram are
A.723°C and 0.02%C
B.723°C and 0.80%C
C.1130°C and 2.00%C
D.1130°C and 4.30%C
271. Steel is made from cast iron by removing
A.Ferrous carbide
B.Carbon
C.Tungsten
D.Sulphur
272. The most important element which controls the physical properties of steel is
A.Silicon
B.Manganese
C.Tungsten
D.Carbon
273. Large amounts of silicon when added to steel will increase the following properties of the steel
A.Mechanical
B.Refractory
C.Corrosive
D.Magnetic
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