This set of Manufacturing Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Manufacturing Engineering Questions & Answers – Fusion Welding Processes-1”.
1. Consider a situation in which a welding operation is being performed with V = 20 volts, I = 200 A, and the cross-sectional area of the weld bead is 30 mm2. Estimate the welding speed if the workpiece and electrode are made of (a) aluminum, (b) carbon steel, and (c) titanium. Use an efficiency of 75%.
a) 35 mm/s
b) 34.5 mm/s
c) 36 mm/s
d) 46 mm/s
Explanation: For aluminum, the specific energy required is u = 2.9 J/mm3
v = e(VI/uA)
= (0.75) [(20/200)/(2.9/30)] = 34.5 mm/s
2. Upon which of the following parameters does the current intensity in arc welding depend?
a) stability of arc
b) electrode diameter
c) gap between the electrode and parent metals
d) thickness of parent metals
Explanation: Electrodes for consumable arc-welding processes are classified according to the following properties:
a) Strength of the deposited weld metal
b) Current (Ac or Dc)
c) Type of coating.
3. In ___________________ welding two non consumable electrodes are used.
c) atomic hydrogen
d) submerged arc
Explanation: In MIG welding consumable electrodes are used. In TIG only one non consumable electrode is used. And in atomic hydrogen welding only two non consumable electrodes are used.
4. ______________ brazing process is good for mass scale.
Explanation: As in furnace brazing at once mass materials could be brazed.
5. For grey cast iron, which of the following welding methods is preferable?
b) submerged arc
c) gas flame
d) electric arc
Explanation: As the percentage of carbon in grey cast iron is less, therefore MIG welding is more preferable.
6. Due to which of the following reasons, no flux is used in atomic hydrogen welding?
a) The burning hydrogen shields the molten metal
b) Two electrodes are coated which gradually release the flux
c) The filler rod is coated with flux
d) One of the two electrodes is coated which releases the flux
7. In resistance welding, between the electrodes, a current of __________ voltage and __________ ampere is passed.
a) high, high
b) high, low
c) low, low
d) low, high
Explanation: As this processes have major advantages, such as not requiring consumable electrodes, shielding gases, or flux.
8. _____________ is the welding process in which heat is produced for welding by chemical reaction.
a) Resisting welding
b) Thermit welding
c) Forge welding
d) Gas welding
Explanation: In forge welding metal is heated in an open hearth. In gas welding heat is produced by pressurizing the gas and in resistance welding heat is produced by electrodes and current. But only in thermit welding heat is produced by chemical reactions.
9. In case of submerged arc welding, the electrodes upto __________diameter may be used.
a) 30 mm
b) 20 mm
c) 15 mm
d) 12 mm
10. In arc welding, arc in created between the electrode and work by
a) contact resistance
b) flow of voltage
c) flow of current
d) electrical energy
11. Material used for coating the electrode is called
c) protective layer
Explanation: Slag is the deposited electrode after welding. Flux is the coating of various materials on electrode.
12. ___________ is the welding process in which two pieces to be joined are overlapped and placed between two pointed electrodes.
a) Seam welding
b) Resistance welding
c) Projection welding
d) Spot welding
Explanation: Spot welding is the simplest and most commonly used resistance~welding process. Welding may be performed by means of single (most common) or multiple pairs of electrodes (as many as a hundred or more), and the required pressure is supplied through mechanical or pneumatic means.
13. Which of the following gases are used in Tungsten inert gas welding?
a) Helium and neon
b) Hydrogen and oxygen
c) Argon and helium
d) Carbon dioxide and hydrogen
14. Preheating is essential in welding
c) cast iron
d) stainless steel
Explanation: As the weldability of cast iron usually decreases as the amount of free carbon in cast iron increases, so it is preheated to a dull red and then welded.
15. The temperature, in arc welding, is of the order of
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