Chemistry · Science General

Metallurgical Processes

1,403 Questions

This section explores key metallurgical processes including ore concentration, pyrometallurgy, and metal refining. It also covers corrosion and the properties of refractory materials. These chemistry questions are relevant for engineering and science entrance tests.

Pyrometallurgy furnacesMetal refining techniquesCorrosion protection methodsOre concentrationAuto reduction process

Metallurgical Processes Questions

Multiple choice

Consider the following statements:

  1. Titanium is used for making boats because it does not corrode by seawater.
  2. Bronze was used for making the Statue of Liberty.

Which of the given statements is/are correct?

  1. Only 1

  2. Only 2

  3. Both 1 and 2

  4. Neither 1 nor 2
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Statement 1 is correct. Titanium is a strong, lustrous, corrosion-resistant (including seawater, aqua regia and chlorine) transition metal with a silver colour. Due to these properties, it is used in making boats. Statement 2 is incorrect. Copper was used for making the Statue of Liberty.

Multiple choice

The process utilizing mainly thermal energy for removing material is

  1. Ultrasonic Machining

  2. Electrochemical Machining

  3. Abrasive Jet Machining

  4. Laser Beam Machining
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

(A) Ultrasonic Machining (UCM) is a mechanical metal removing process for brittle material by using high frequency oscillations of shaped tool using abrasive slurry. (B) Electro Chemical Machining (ECM) uses electrical current to remove the metal relies on the principle of electrolysis for material removal. (C) Abrasive water jet machining is a process that uses a very high speed water jet mixed with abrasives to cut any type of matarial. (D) Laser beam machining utiliser the energy from the coherent light beam which first melt and then vaporise the tiny metal particles, in which thermal energy is used.

Multiple choice

The hot tearing in a metal casting is due to

  1. high fluidity

  2. high melt temperature

  3. wide range of solidification temperature

  4. low coefficient of thermal expansion
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Hot tears in metal costing is a metallurgical defect which is also called hot cracking occurs as casting cools. This happens because the metal is weak when it is hot and residual stresses in the metal can cause the casting to fail as it cools. Proper mould design prevent this type of casting. So that uniform cooling rate for all parts can be maintained which reduce the range of solidification temperature.

Multiple choice

Match the casting defects (Group A) with the probable causes (Group B).

     
Group A
Group B
P Hot tears 1 Improper fusion of two streams of liquid metal
Q Shrinkage 2 Low permeability of the sand mould
R Blow holes 3 Volumetric contraction both in liquid and solid stage
4 Stresses in different regions of metal

  1. P - 1, Q - 3, R - 2, S - 4

  2. P - 4, Q - 3, R - 2, S - 1

  3. P - 3, Q - 4, R - 2, S - 1

  4. P - 1, Q - 2, R - 4, S - 3
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

(P) Hot tears is a metallurgical defect and occurs because of differential cooling rate, which creates stresses in the different regions of metal. (Q) Shrinkage occurs because of volumetric contraction as volume gets reduced during cooling. (R) Blow holes is a gas defect which occurs due to low permeability of sand mould. (S) Cold shut is pouring metal which appears due to improper fusion of two streams of liquid metal.

Multiple choice

With respect to metal working, match Group A with Group B:

     
Group A Group B
P : Defect in extrusion I : alligatoring
Q : Defect in rolling II : scab
R : Product of akew rolling III : fish tail
S : Product of rolling through cluster mill IV : seamless tube
V : thin sheet with tight tolerance
VI : semi-finished balls of ball bearing

  1. P - II, Q - III, R - VI, S - V

  2. P - III, Q - I, R - VI, S - V

  3. P - III, Q - I, R - IV, S - VI

  4. P - I, Q - II, R - V, S - VI
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In extrusion defeat will be fish tail. In rolling defect will be alligatoring. Due to skew rolling we get semi-finished balls. We get thin sheet with tight tolerance as a product of rolling through cluster mill. So P - III, Q - I, R - VI, S - V

Multiple choice

Within the Heat Affected Zone (HAZ) in a fusion welding process, the work material undergoes

  1. microstructural changes but does not melt

  2. neither melting nor microstructural changes

  3. both melting and microstructural changes after solidification

  4. melting and retains the original microstructure after solidification
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The heat affected zone (HAZ) is the area of base metal which is not melted & has had its micro structural & properties altered in Fusion welding. The extend & magnitude of property change depends primarily on the base material, the well filler metal, amount & concentration heat input by Fusion weld process.

Multiple choice

Match the heat treatment processes (Group A) and their associated effects on properties (Group B) of medium carbon steel

     
Group A Group B
P Tempering I Strengthening and grain refinement
Q Quenching II Inducing toughness
R Annealing III Hardening
S Normalizing IV Softening

  1. P - III, Q - IV, R - II, S - I

  2. P - II, Q - III, R - IV, S - I

  3. P - III, Q - II, R - IV, S - I

  4. P - II, Q - III, R - I, S - IV
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

(P) Tempering is process of inducing toughness. (Q) Quenching is done to make metal hard & main objective is to produce martensite (R) Annealing is done to soften the material & Quenching medium of annealing is Furnace. (S) Normalizing refined the grain structure & strengthened the material. Quenching medium of annealing is air.

Multiple choice

The major difficulty during welding of aluminium is due to its

  1. high tendency of oxidation

  2. high thermal conductivity

  3. low melting point

  4. low density
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Aluminium has high tendency of oxidation so during welding it is converted into aluminium oxide (Al2O3) and Al2O3 has very high melting point (2702oC) so now it will not melt and welding can not be performed easily.

Multiple choice

Which one among the following welding processes uses non-consumable electrode?

  1. Gas metal arc welding

  2. Submerged arc welding

  3. Gas tungsten arc welding

  4. Flux coated arc welding
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

GTAW is also called as Tungsten Inert Gas Welding (TIG). The arc is maintained between the work piece and a tungsten electrode by an inert gas. The electrode is non-consumable since its melting point is about $3400^0C.$

Multiple choice

Match the following non-traditional machining processes with the corresponding material removal mechanisms:

Mechanical process| Mechanism of material removal| | P. Chemical machining| 1. Erosion| | Q. Electro-chemical machining| 2. Corrosive reaction| | R. Electro - discharge machining| 3. Ion displacement| | S. Ultrasonic machining| 4. Fusion and vapourization|

  1. P-2, Q-3, R-4, S-1

  2. P-2, Q-4, R-3, S-1

  3. P-3, Q-2, R-4, S-1

  4. P-2, Q-3, R-1, S-4
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation