Engineering Materials - Study Mode

[#186] The percentage of carbon in cast iron varies from
Correct Answer

(D) 1.7 to 4.5

Explanation

Solution: Cast iron is a ferrous alloy which has more than 2% carbon in it. Though it can have any percentage of carbon between 2% to 6.67%, but practically it is in between 2% to 4% only.

[#187] An important property of high silicon (12 - 18%) cast iron is the high
Correct Answer

(A) Hardness

Explanation

Solution: High silicon iron-based alloys are excellent corrosion resistant materials with advantages of superior corrosion resistant properties, low cost and saving on noble metals such as nickel and chromium. When containing 14.5% or more silicon, the corrosion resistance of these iron-based alloys is better than that of some cast irons containing a significant amount of chromium, nickel and/or molybdenum, and even than that of certain nickel based alloys in some severe corrosion conditions.

[#188] Which of the following material has maximum ductility?
Correct Answer

(A) Mild steel

Explanation

Solution: Mild steel has maximum ductility. Those materials show the lower amount of the carbon. Alloying elements from one metal to another metal. Some materials can have the inherent ability to withstand when the tensile load has been applied pave of the materials like low carbon steels and medium carbon steel shows somehow desirables properties like ductility.

[#189] The ability of a material to resist softening at high temperature is known as
Correct Answer

(C) Hot hardness

Explanation

Solution: hot hardness or red hardness corresponds to hardness of a material at high temperatures. As the temperature of material increases, hardness decreases and at some point a drastic change in hardness occurs

[#190] The defect which takes place due to imperfect packing of atoms during crystallization is known as
Correct Answer

(C) Point defect

Explanation

Solution: Point defects are where an atom is missing or is in an irregular place in the lattice structure. Point defects include self interstitial atoms, interstitial impurity atoms, substitutional atoms and vacancies