Carbon steel is_______________?
(A) made by adding carbon in steel
(B) refined from cast iron
(C) an alloy of iron and carbon with varying quantities of phosphorus and sulphur
(D) extensively used for making cutting tools
(D) extremely brittle
‘Killed steels’ are those steels__________________?
(A) which are destroyed by burning
(B) which after their destruction are recycled to produce fresh steel
(C) which are deoxidised in the ladle with silicon and aluminium
(D) in which carbon is completely burnt
(D) which have poor properties due to improper manufacturing
The most effective inhibitor of grain growth, when added in small quantities is__________________?
(A) carbon
(B) vanadium
(C) manganese
(D) cobalt
(D) copper
Maximum percentage of carbon in ferrite is___________________?
(A) 0.025%
(B) 0.06%
(C) 0.1%
(D) 0.25%
(D) 0.8%.
Corrosion resistance of steel is increased by addition of________________?
(A) chromium and nickel
(B) sulphur, phosphorus, lead
(C) vanadium, aluminium
(D) tungsten, molybdenum, vanadium, chromium
(D) zinc
Pure iron is the structure of_______________?
(A) ferrite
(B) pearlite
(C) anstenite
(D) ferrite and cementite
(D) ferrite and pearlite
Cast iron is characterised by minimum of following %age of carbon_________________?
(A) 0.2%
(B) 0.8%
(C) 1.3%
(D) 2%
(D) 6.3%.
The molecules in a solid move______________?
(A) in a random manner
(B) in a haphazard way
(C) in circular motion
(D) back and forth like tiny pendulums
(D) do not move
Paramagnetic alpha iron changes to gamma iron at_______________?
(A) 770°C
(B) 910°C
(C) 1440°C
(D) 1539°C
(D) none of the above
The crystal structure of gamma iron is_________________?
(A) body centred cubic
(B) face centred cubic
(C) hexagonal close packed
(D) cubic structure
(D) orthorhombic crystal