AZ L-78 Industrial Welding Contractor
Exam Questions and Correct Answers
(Verified Answers) Plus Rationale 2027
Q&A| Instant Download Pdf
1. Which welding process uses a continuously fed consumable wire
electrode and an externally supplied shielding gas?
a. Shielded metal arc welding (SMAW)
b. Gas tungsten arc welding (GTAW)
c. Gas metal arc welding (GMAW)
d. Oxyfuel welding
Rationale: GMAW uses a continuously supplied wire electrode that
serves as both the electrode and filler metal. Shielding gas protects the
molten weld pool from atmospheric contamination. SMAW uses coated
electrodes, GTAW uses a nonconsumable tungsten electrode, and
oxyfuel welding uses a flame rather than an electric arc.
2. What is the primary purpose of shielding gas during arc welding?
,a. Increase the hardness of the base metal
b. Cool the welding electrode
c. Increase electrical resistance
d. Prevent atmospheric contamination of the molten weld pool
Rationale: Oxygen, nitrogen, and moisture from the atmosphere can
cause porosity, embrittlement, oxidation, and other weld defects.
Shielding gas creates a protective atmosphere around the arc and
molten metal.
3. In shielded metal arc welding, what provides shielding for the
molten weld pool?
a. Compressed air
b. The flux coating on the electrode
c. Cooling water
d. Welding-grade nitrogen only
Rationale: SMAW electrodes have a flux coating that decomposes
during welding and produces shielding gases and slag. This protects the
molten metal from atmospheric contamination.
4. Which welding process uses a nonconsumable tungsten
electrode?
,a. SMAW
b. GMAW
c. FCAW
d. GTAW
Rationale: Gas tungsten arc welding uses a tungsten electrode that is
not normally consumed during welding. Filler metal, when required, is
added separately.
5. What is the main function of welding flux?
a. Eliminate the need for heat
b. Protect and chemically clean the weld area while helping form slag
c. Replace the base metal
d. Reduce the electrode diameter
Rationale: Flux performs several functions, including shielding the weld
pool, removing or preventing oxides, and forming a protective slag
layer. Its exact function varies by welding process and consumable.
6. Which weld joint has two members meeting approximately at
right angles?
a. Butt joint
b. Lap joint
, c. T-joint
d. Edge joint
Rationale: A T-joint forms a configuration resembling the letter T, with
one member intersecting another approximately at 90 degrees. Fillet
welds are commonly used on T-joints.
7. A groove weld is most commonly used to join what type of joint
configuration?
a. Only lap joints
b. Members aligned with a prepared groove between them
c. Only circular joints
d. Only temporary attachments
Rationale: Groove welds are deposited in a groove formed between two
members. Groove preparation can include square, V, U, J, or other
configurations depending on material thickness and welding
requirements.
8. What does the term “weld penetration” describe?
a. The width of the weld face
b. The height of reinforcement
c. The depth to which the weld metal extends into the base metal or
Exam Questions and Correct Answers
(Verified Answers) Plus Rationale 2027
Q&A| Instant Download Pdf
1. Which welding process uses a continuously fed consumable wire
electrode and an externally supplied shielding gas?
a. Shielded metal arc welding (SMAW)
b. Gas tungsten arc welding (GTAW)
c. Gas metal arc welding (GMAW)
d. Oxyfuel welding
Rationale: GMAW uses a continuously supplied wire electrode that
serves as both the electrode and filler metal. Shielding gas protects the
molten weld pool from atmospheric contamination. SMAW uses coated
electrodes, GTAW uses a nonconsumable tungsten electrode, and
oxyfuel welding uses a flame rather than an electric arc.
2. What is the primary purpose of shielding gas during arc welding?
,a. Increase the hardness of the base metal
b. Cool the welding electrode
c. Increase electrical resistance
d. Prevent atmospheric contamination of the molten weld pool
Rationale: Oxygen, nitrogen, and moisture from the atmosphere can
cause porosity, embrittlement, oxidation, and other weld defects.
Shielding gas creates a protective atmosphere around the arc and
molten metal.
3. In shielded metal arc welding, what provides shielding for the
molten weld pool?
a. Compressed air
b. The flux coating on the electrode
c. Cooling water
d. Welding-grade nitrogen only
Rationale: SMAW electrodes have a flux coating that decomposes
during welding and produces shielding gases and slag. This protects the
molten metal from atmospheric contamination.
4. Which welding process uses a nonconsumable tungsten
electrode?
,a. SMAW
b. GMAW
c. FCAW
d. GTAW
Rationale: Gas tungsten arc welding uses a tungsten electrode that is
not normally consumed during welding. Filler metal, when required, is
added separately.
5. What is the main function of welding flux?
a. Eliminate the need for heat
b. Protect and chemically clean the weld area while helping form slag
c. Replace the base metal
d. Reduce the electrode diameter
Rationale: Flux performs several functions, including shielding the weld
pool, removing or preventing oxides, and forming a protective slag
layer. Its exact function varies by welding process and consumable.
6. Which weld joint has two members meeting approximately at
right angles?
a. Butt joint
b. Lap joint
, c. T-joint
d. Edge joint
Rationale: A T-joint forms a configuration resembling the letter T, with
one member intersecting another approximately at 90 degrees. Fillet
welds are commonly used on T-joints.
7. A groove weld is most commonly used to join what type of joint
configuration?
a. Only lap joints
b. Members aligned with a prepared groove between them
c. Only circular joints
d. Only temporary attachments
Rationale: Groove welds are deposited in a groove formed between two
members. Groove preparation can include square, V, U, J, or other
configurations depending on material thickness and welding
requirements.
8. What does the term “weld penetration” describe?
a. The width of the weld face
b. The height of reinforcement
c. The depth to which the weld metal extends into the base metal or
