Engineering Materials - Study Mode
[#206] The machinability of steel is increased by
Correct Answer
(B) Phosphorous, lead and sulphur
Explanation
Solution: Phosphorous, lead and sulphur improves machinability and resistance to corrosion and it intensifies the effects of other alloying elements
[#207] The hardness is the property of a material due to which it
Correct Answer
(C) Can cut another metal
Explanation
Solution: Hardness is a measure of the resistance to localized plastic deformation induced by either mechanical indentation or abrasion.
[#208] White cast iron has
Correct Answer
(D) All of these
Explanation
Solution: When white iron is sheared, the fractured face appears white due to the absence of graphite. The cementite microcrystalline structure is hard and brittle with a high compressive strength and good wear resistance. In certain specialized applications, it is desirable to have white iron on the surface of the product. This can be achieved by using a good conductor of heat to make part of the mold. This will draw heat out of the molten metal quickly from that specific area, while the rest of the casting cools at a slower rate.
[#209] When a steel containing __________ 0.8% carbon is cooled slowly below the lower critical point, it consists of ferrite and pearlite.
Correct Answer
(B) Less than
Explanation
Solution: When a steel containing less than 0.8% carbon is cooled slowly below the lower critical point, it consists of ferrite and pearlite.
[#210] The ratio of the volume occupied by the atoms to the total volume of the unit cell is called
Correct Answer
(B) Atomic packing factor
Explanation
Solution: The ratio of the volume occupied by the atoms to the total volume of the unit cell is called Atomic packing factor