০২। A carbon steel having Brinell hardness number 100 should have ultimate tensile strength closer to
ক) 100 N/mm2
খ) 200 N/mm2
গ) 350 N/mm2
ঘ) 1000 N/mm2
০৩। A coarse grained steel
ক) is less tough and has a greater tendency to distort during heat treatment
খ) is more ductile and has a less tendency to distort during heat treatment
গ) is less tough and has a less tendency to distort during heat treatment
ঘ) is more ductile and has a greater tendency to distort during heat treatment
০৪। A fine grained steel
ক) is less tough and has a greater tendency to distort during heat treatment
খ) is more ductile and has a less tendency to distort during heat treatment
গ) is less tough and has a less tendency to distort during heat treatment
ঘ) is more ductile and has a greater tendency to distort during heat treatment
০৫। A material is said to be allotropic, if it has
ক) fixed structure at all temperatures
খ) atoms distributed in random pattern
গ) different crystal structures at different temperatures
ঘ) any one of the above
০৬। A small percentage of boron is added to steel in order to
ক) increase hardenability
খ) reduce machinability
গ) increase wear resistance
ঘ) increase endurance strength
০৭। A steel alloy containing 36% nickel is called
ক) stainless steel
খ) high speed steel
গ) invar
ঘ) heat resisting steel
০৮। A steel containing 12 to 14% chromium and 0.12 to 0.35% carbon is called martensitic stainless steel.
ক) True
খ) False
০৯। A steel containing 16 to 18% chromium and about 0.12% carbon is called
ক) ferritic stainless steel
খ) austenitic stainless steel
গ) martensitic stainless steel
ঘ) nickel steel
১০। A steel containing ferrite and pearlite is
ক) hard
খ) soft
গ) tough
ঘ) hard and tough
১১। A steel is heated at about 875° C where the structure consists of entirely austenite. It is then cooled suddenly at a temperature of about 250° C to 525° C. This process of heat treatment is known as
ক) normalising
খ) annealing
গ) austempering
ঘ) martempering
১২। A steel with 0.8% carbon and 100% pearlite is called
ক) eutectoid steel
খ) hypo-eutectoid steel
গ) hyper-eutectoid steel
ঘ) none of these
১৩। A steel with 0.8% carbon is known as
ক) eutectoid steel
খ) hyper-eutectoid steel
গ) hypo-eutectiod steel
ঘ) none of these
১৪। A steel with carbon above 0.8% is known as hyper-eutectoid steel.
ক) Agree
খ) Disagree
১৫। A steel with carbon __________ is known as hypo-eutectoid steel.
ক) 0.8%
খ) below 0.8%
গ) above 0.8%
১৬। According to Indian standard specifications, a plain carbon steel designated by 40 C8 means that the carbon content is
ক) 0.04%
খ) 0.35 to 0.45%
গ) 0.4 to 0.6%
ঘ) 0.6 to 0.8%
১৭। According to Indian standard specifications, cast iron designated by ‘FG 150’ means
ক) white cast iron with B.H.N. 150
খ) white cast iron with 150 MPa as minimum compressive strength
গ) grey cast iron with B.H.N. 150
ঘ) grey cast iron with 150 MPa as minimum tensile strength
১৮। According to Indian standard specifications, SG 400/15 means
ক) spheroidal graphite cast iron with B.H.N. 400 and minimum tensile strength 15 MPa
খ) spheroidal graphite cast iron with minimum tensile strength 400 MPa and 15 percent elongation
গ) spheroidal graphite cast iron with minimum compressive strength 400 MPa and 15 percent reduction in area