Multiple Choice Questions and Answers (MCQs) on Manufacturing and Production Engineering

01. If a gas metal arc process uses a low arc voltage and the arc is continuously interrupted as the molten electrode metal fills up the arc gap is known as

(A) ARC
(B) Short ARC
(C) ARC length
(D) ARC blow

Answer: Option B

Explanation: In short ARC, Gas metals are processes use a law are voltage. The arc is continuously interrupted as the molten electrode metal bridges the arc gap.

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

(A) Gas metal arc welding
(B) Submerged arc welding
(C) Gas tungsten arc welding
(D) Flux coated arc welding

Answer: Option C

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 3400⁰C.

03. What type of fusion welding process is used for welding sheet metals of all engineering metals (except Cu, Ag) in automobile and air craft industries, pipe and tubing production?

(A) Thermit welding
(B) Electroslag welding
(C) Resistance welding
(D) Submerged arc welding

Answer: Option C

Explanation: Resistance Welding is used for welding sheet metals of all engineering metals (except Cu, Ag) in automobile and air craft industries, pipe and tubing production. It’s a type of fusion welding process.

04. When two main plates are kept in alignment butting each other and riveted with cover plate on both sides of the main plates with two rows of rivets in each main plate, the joint is known as _______ double cover butt joint.

(A) Single riveted
(B) Double riveted
(C) Both (A) and (B)
(D) None of these

Answer: Option B

05. In a metal arc welding process, a gas metal arc welding with magnetized flux is used and can be done in all the positions i.e. flat position, vertical position or inclined position.

(A) Globular transfer
(B) Spray transfer
(C) GMAW practice
(D) Dip transfer

Answer: Option C

Explanation: GMAW practice is a gas metal arc welding with magnetized flux and this type of welding can be done successfully on most of the commercial metals, if proper welding wire and proper gases are chosen and the proper settings are made. It can be done in all the positions i.e. flat position, vertical position or inclined position.

06. In a particular type of welding, flux is prepared in the form of a coarse powder and granulated flux is spread over the joint. What is this type of welding process called?

(A) Electric arc welding
(B) Submerged arc welding
(C) MIG welding
(D) TIG welding

Answer: Option B

Explanation: In submerged type of arc welding, flux is prepared in the form of coarse powder granulated flux is spread over the joint.

07. The common welding error that occurs due to shrinkage of weld metal, faulty clamping of parts, faulty penetration or overheating at joints is called?

(A) Distortion
(B) Warping
(C) Porous weld
(D) Poor fusion

Answer: Option B

Explanation: Warping occurs due to shrinkage of weld metal, faulty clamping of parts, faulty penetration or overheating at joint.

08. The object of caulking in a riveted joint is to make the joint

(A) Free from corrosion
(B) Stronger in tension
(C) Free from stresses
(D) Leak-proof

Answer: Option D

09. Calculate the weld per minute, work speed of circular electrode of 220 mm diameter for carrying out seam welding at 4 welds per cm on 1.6 mm thick mild steel tube. Welding cycle consists of 3 cycles ‘on’ and 2 cycles ‘off’ Power supply is at 50 Hz.

(A) 3000 welds / min, 75 mm / min
(B) 600 welds / min, 1500 mm / min
(C) 500 welds/ min, 1250 mm/min
(D) 22 welds / min, 55 mm / min

Answer: Option B

Solution: Weld per min = (frequency × 60)/ (cycles for weld + interval cycles)

= (50 × 60)/ (3 + 2) = 600 welds/ min.

Work speed (mm / min) = (welds/ min) / weld required per mm

= 600 / (4/10) = 1500 mm/ min

10. What is the method of brazing used to join relatively small assemblies made from materials that either do not oxidize at the brazing temperature or can be protected from oxidation with a flux?

(A) Torch brazing
(B) Dip brazing
(C) Resistance brazing
(D) Furnace brazing

Answer: Option A

Explanation: Torch brazing is used to join relatively small assemblies made from materials that either do not oxidize at the brazing temperature or can be protected from oxidation with a flux. Aluminium-Silicon alloys, silver base alloys and copper-zinc alloys are used as the filler metals with proper flux. The self-fluxing copper phosphorus alloys are also used.

11. Work speed of circular electrode of 220 mm diameter for carrying out seam welding at 4 welds per cm on 1.6 mm thick mild steel tube. Welding cycle consists of 3 cycles ‘on’ and 2 cycles ‘off’ Power supply is at 50 Hz. Calculate R.P.M. and energy requirement of the above circular electrodes assuming effective resistance between electrodes as 100 ohm.

(A) 2.17 rpm, 600 joules
(B) 6.8 rpm, 6 joules
(C) 5.03 rpm, 600 joules
(D) 22 rpm, 600 joules

Answer: Option A

Solution: Weld per min = (frequency × 60)/ (cycles for weld + interval cycles)

= (50 × 60)/ (3 + 2) = 600 welds/ min.

Work speed (mm / min) = (welds/ min) / weld required per mm

= 600 / (4/10) = 1500 mm/ min.

Therefore, RPM of electrode = work speed in mm per min/ π × electrode diameter in mm

= 1500/ (3.14 × 220) = 2.17 rpm.

For 1.6 mm thick M.S. Plate, current requirement is around 10,000 amperes Therefore, Energy required = I²RT = (10, 000²) × 100 × (3/ 50) = 600 Joules.

12. In DC arc welding, if leads are arranged in work as Negative pole of the welding arc and electrode as Positive pole of the welding arc, the arrangement is known as

(A) Fusion
(B) Reverse polarity
(C) Forward welding
(D) Direct polarity

Answer: Option B

13. What is the welding defect caused due to improper control and poor removal of slog between passes called?

(A) Mismatch
(B) Under fill
(C) Crack
(D) Porosity

Answer: Option B

Explanation: Under fill is the welding defect caused due to improper control and poor removal of slag between passes.

14. The common welding error that occurs due to wrong speed, faulty preparation, and high / low current, improper electrode size is called?

(A) Distortion
(B) Warping
(C) Porous weld
(D) Poor fusion

Answer: Option D

Explanation: Poor fusion could be due to wrong speed, faulty preparation, and high / low current, improper electrode size.

15. What is the type of welding defect caused due to shrinkage during solidification and by weld stresses called?

(A) Incomplete fusion
(B) Lamellar tearing
(C) Mismatch
(D) Shrinkage void

Answer: Option B

Explanation: Lamellar tearing is caused due to shrinkage during solidification and by weld stresses.

16. In abrasive jet machining, as the distance between the nozzle tip and the work surface increases, the material removal rate

(A) Increases continuously
(B) Decreases continuously
(C) Decreases, becomes stable and then increases.
(D) Increases, becomes stable and then decreases.

Answer: Option D

Explanation: The material removal rate is first increases because of area of jet increase than becomes stable and then decreases due to decrease in jet velocity.

17. Match the following metal forming processes with their associated stresses in the work piece.

Metal forming process Types of stress
1. Coining P. Tensile
2. Wire Drawing Q. Shear
3. Blanking R. Tensile and Compressive
4. Deep Drawing S. Compressive

(A) 1-S, 2-P, 3-Q, 4-R

(B) 1-S, 2-P, 3-R, 4-Q

(C) 1-P, 2-Q, 3-S, 4-R

(D) 1-P, 2-R, 3-Q, 4-S

Answer: Option A

Explanation:

Metal forming process Types of stress
1. Coining S. Compressive
2. Wire Drawing P. Tensile
3. Blanking Q. Shear
4. Deep Drawing R. Tensile and Compressive

18. In an interchangeable assembly, shafts of size 25.000 -0.010⁺⁰∙⁰⁴⁰ mm mate with holes of size 25.000 -0.020⁺⁰∙⁰³⁰, the maximum interference (in microns) in the assembly is

(A) 40
(B) 30
(C) 20
(D) 10

Answer: Option C

Explanation: Maximum Interference = Maximum limit of shat −Minimum limit of hole

= (25 + 0.040) − (25 + 0.020) = 0.02mm = 20 microns

19. During normalizing process of steel, the specimen is heated

(A) Between the upper and lower critical temperature and cooled in still air.
(B) Above the upper critical temperature and cooled in furnace.
(C) Above the upper critical temperature and cooled in still air.
(D) Between the upper and lower critical temperature and cooled in furnace.

Answer: Option C

Explanation: Normalising involves prolonged heating just above the critical temperature to produce globular form of carbine and then cooling in air.

20. A CNC vertical milling machine has to cut a straight slot of 10 mm width and 2mm depth by a cutter of 10 mm diameter between points (0,0) and (100,100) on the XY plane (dimensions in mm). The feed rate used for milling is 50 mm/min, milling time for the slot (in seconds) is

(A) 120
(B) 170
(C) 180
(D) 240

Answer: Option B

Explanation: Given data, width (b) = 10 mm, depth = 2mm

Distance travelled for cut between points (0, 0) and (100,100) By Pythagoras theorem d = √(100²+ 100²) = 141.42mm

Feed rate f = 50 mm/min = 50/ 60 = 0.833 mm/ sec.

Time required to cut the distance (d) t = d/f = 141.42/ 0.833 = 169.7 ≈ 170 sec.

21. A solid cylinder of diameter 100 mm and height 50 mm is forged between two frictionless flat dies to a height of 25mm. The percentage change in diameter is

(A) 0
(B) 2.07
(C) 20.7
(D) 41.4

Answer: Option D

Explanation: Since volume of cylinder remains same.

Therefore, Volume before forging = Volume after forging

πd₁²/ 4 = πd₂²/ 4

or, d₂ = 141.42

Percentage change in diameter = {(d₂ – d₁)/ d₁} × 100 = 41.42%

22. The maximum possible draft in cold rolling of sheet increases with the

(A) Increase in coefficient of friction
(B) Decrease in coefficient of friction
(C) Decrease in roll radius
(D) Decrease in roll velocity

Answer: Option A

Explanation: The main objective in rolling is to decrease the thickness of the metal. The relation for the rolling is given by, F = µPr

Where; F = tangential frictional force
µ = Coefficient of friction
Pr= Normal force between the roll and work piece

Now, from the increase in µ the draft in cold rolling of sheet increases.

23. The operation in which oil is permeated into the pores of a powder metallurgy product is known as

(A) Mixing
(B) Sintering
(C) Impregnation
(D) Infiltration

Answer: Option C

Explanation: If the pores in a sintered compact are filled with oil, the operation is called as impregnation. The lubricants are added to the porous bearings, gears and pump rotors etc.

24. A hole is of dimension φ = 9 ₊0⁺⁰∙⁰¹⁵ mm. The corresponding shaft is of dimension φ = 9 ₊0.001⁺⁰∙⁰¹⁰ mm. The resulting assembly has

(A) Loose running fit
(B) Close running fit
(C) Transition fit
(D) Interference fit

Answer: Option C

25. The crystal structure of austenite is

(A) Body centred cubic
(B) Base centred cubic
(C) Hexagonal closed packed
(D) Body centred tetragonal

Answer: Option B