Engineering Materials - Study Mode
[#81] In malleable iron, carbon is present in the form of
Correct Answer
(D) Nodular aggregates of graphite
Explanation
Solution: In malleable iron, carbon is present in the form of Nodular aggregates of graphite
[#82] Nodular iron has
Correct Answer
(D) All of the above
Explanation
Solution: nodular iron, obtains its special properties through the addition of magnesium into the alloy. The presence of magnesium causes the graphite to form in a spheroid shape as opposed to the flakes of gray iron. Composition control is very important in the manufacturing process. Small amounts of impurities such as sulfur and oxygen react with the magnesium, affecting the shape of the graphite molecules. Different grades of ductile iron are formed by manipulating the microcrystalline structure around the graphite spheroid. This is achieved through the casting process, or through heat treatment, as a downstream processing step.
[#83] Nickel in steel
Correct Answer
(D) Gives ductility, toughness, tensile strength and anti-corrosion properties
Explanation
Solution: Nickel in steel Gives ductility, toughness, tensile strength and anti-corrosion properties.
[#84] Dislocations in materials refer to the following type of defect
Correct Answer
(B) Line defect
Explanation
Solution: Dislocations in materials refer to Line defect. Line defects are lines along which whole rows of atoms in a solid are arranged anomalously. The resulting irregularity in spacing is most severe along a line called the line of dislocation. Line defects can weaken or strengthen solids.
[#85] The main alloying elements high speed steel in order of increasing proportion are
Correct Answer
(A) Vanadium, chromium, tungsten
Explanation
Solution: : High-speed steel (HSS) is an alloy known for its high hardness and resistance to abrasion, making it ideal for cutting tools. The main alloying elements are added in specific proportions to achieve these properties. Vanadium is present in the smallest proportion among the three listed elements, followed by chromium , and then tungsten in the highest proportion. Vanadium improves the wear resistance and hardness. Chromium enhances the toughness and corrosion resistance. Tungsten increases the hardness, hot hardness, and wear resistance of the steel.