WELDING MCQ SET 3
Q1. Arc blow is a common problem in:
A) AC welding
B) DC welding
C) Gas welding
D) TIG welding
Answer: B) DC welding
Explanation: Arc blow occurs due to magnetic field interference around DC arcs.
Q2. Tungsten Inert Gas (TIG) welding is also known as:
A) Gas metal arc welding
B) Gas tungsten arc welding
C) Submerged arc welding
D) Plasma welding
Answer: B) Gas tungsten arc welding
Explanation: TIG = GTAW, uses tungsten electrode and inert gas (argon/helium).
Q3. In TIG welding, the shielding gas used is:
A) Oxygen
B) Nitrogen
C) Argon or helium
D) Carbon dioxide
Answer: C) Argon or helium
Explanation: Inert gases protect molten metal from oxidation and contamination.
Q4. In MIG welding, the gas used for shielding is:
A) COโ or Argon
B) Hydrogen
C) Nitrogen
D) Ammonia
Answer: A) COโ or Argon
Explanation: MIG uses inert or semi-inert gases to shield the molten weld pool.
Q5. The main difference between TIG and MIG welding is:
A) Type of current
B) Type of gas
C) Type of electrode
D) None
Answer: C) Type of electrode
Explanation: TIG uses a non-consumable tungsten electrode; MIG uses a consumable wire electrode.
Q6. The main function of slag in welding is:
A) To cool the weld
B) To protect molten metal from air
C) To reduce heat
D) To increase arc length
Answer: B) To protect molten metal from air
Explanation: Slag forms a layer over the molten weld pool, preventing oxidation and contamination from the atmosphere.
Q7. The electrode number E6013 indicates:
A) Type of gas used
B) Strength and position of use
C) Type of metal
D) Type of current
Answer: B) Strength and position of use
Explanation: In E6013, โ60โ = tensile strength (60,000 psi), โ1โ = any position, and โ3โ = flux type.
Q8. The term โH.A.Zโ in welding stands for:
A) Heat Affected Zone
B) Hot Air Zone
C) High Arc Zone
D) Heated Alloy Zone
Answer: A) Heat Affected Zone
Explanation: HAZ is the area around the weld that did not melt but whose properties were changed by heat.
Q9. Which one is a fusion welding process?
A) Soldering
B) Brazing
C) Arc welding
D) Riveting
Answer: C) Arc welding
Explanation: Fusion welding melts the base metals; soldering and brazing do not.
Q10. The most common defect in welding is:
A) Porosity
B) Smooth surface
C) Perfect bead
D) Even penetration
Answer: A) Porosity
Explanation: Porosity occurs when gas is trapped inside the molten weld pool and forms cavities.
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