NOCTI Welding Test Questions And Correct
Answers (Verified Answers) Plus Rationales
2027 Q&A | Instant Download Pdf
1. Which welding process uses a continuously fed consumable wire
electrode and a shielding gas?
A. SMAW
B. GTAW
C. GMAW
D. FCAW-S
Answer: C. GMAW
Rationale: Gas Metal Arc Welding (GMAW or MIG) uses a continuously
fed consumable wire electrode and an external shielding gas to protect
the weld pool from atmospheric contamination. It is commonly used in
manufacturing due to its high productivity.
2. What is the primary purpose of shielding gas during welding?
,A. Increase electrode hardness
B. Cool the base metal
C. Protect the molten weld pool from contamination
D. Increase electrical resistance
Answer: C. Protect the molten weld pool from contamination
Rationale: Shielding gas prevents oxygen, nitrogen, and moisture from
contaminating the molten weld, reducing porosity and improving weld
quality.
3. Which electrode classification is commonly used for welding mild
steel with SMAW?
A. E6010
B. ER308L
C. E4043
D. E11018M-H8
Answer: A. E6010
Rationale: E6010 is a cellulose-coated electrode known for deep
penetration and excellent performance on mild steel, particularly in pipe
welding and root passes.
, 4. In welding, the heat-affected zone (HAZ) refers to:
A. The weld bead only
B. Metal melted by the arc
C. Base metal altered by heat but not melted
D. Slag covering the weld
Answer: C. Base metal altered by heat but not melted
Rationale: The HAZ experiences changes in microstructure due to
welding heat without melting, making it an important area for
evaluating weld integrity.
5. Which welding position is designated as "1G"?
A. Horizontal groove
B. Vertical groove
C. Flat groove
D. Overhead groove
Answer: C. Flat groove
Rationale: The 1G position is the flat groove welding position, generally
considered the easiest because gravity assists in controlling the molten
weld pool.
, 6. Which gas is commonly used as the shielding gas for GTAW on
stainless steel?
A. Oxygen
B. Nitrogen
C. Argon
D. Carbon dioxide
Answer: C. Argon
Rationale: Pure argon provides stable arc characteristics, excellent
shielding, and clean welds, making it the preferred shielding gas for
GTAW.
7. Which defect is characterized by small gas pockets trapped in the
weld?
A. Cracking
B. Porosity
C. Undercut
D. Overlap
Answer: B. Porosity
Answers (Verified Answers) Plus Rationales
2027 Q&A | Instant Download Pdf
1. Which welding process uses a continuously fed consumable wire
electrode and a shielding gas?
A. SMAW
B. GTAW
C. GMAW
D. FCAW-S
Answer: C. GMAW
Rationale: Gas Metal Arc Welding (GMAW or MIG) uses a continuously
fed consumable wire electrode and an external shielding gas to protect
the weld pool from atmospheric contamination. It is commonly used in
manufacturing due to its high productivity.
2. What is the primary purpose of shielding gas during welding?
,A. Increase electrode hardness
B. Cool the base metal
C. Protect the molten weld pool from contamination
D. Increase electrical resistance
Answer: C. Protect the molten weld pool from contamination
Rationale: Shielding gas prevents oxygen, nitrogen, and moisture from
contaminating the molten weld, reducing porosity and improving weld
quality.
3. Which electrode classification is commonly used for welding mild
steel with SMAW?
A. E6010
B. ER308L
C. E4043
D. E11018M-H8
Answer: A. E6010
Rationale: E6010 is a cellulose-coated electrode known for deep
penetration and excellent performance on mild steel, particularly in pipe
welding and root passes.
, 4. In welding, the heat-affected zone (HAZ) refers to:
A. The weld bead only
B. Metal melted by the arc
C. Base metal altered by heat but not melted
D. Slag covering the weld
Answer: C. Base metal altered by heat but not melted
Rationale: The HAZ experiences changes in microstructure due to
welding heat without melting, making it an important area for
evaluating weld integrity.
5. Which welding position is designated as "1G"?
A. Horizontal groove
B. Vertical groove
C. Flat groove
D. Overhead groove
Answer: C. Flat groove
Rationale: The 1G position is the flat groove welding position, generally
considered the easiest because gravity assists in controlling the molten
weld pool.
, 6. Which gas is commonly used as the shielding gas for GTAW on
stainless steel?
A. Oxygen
B. Nitrogen
C. Argon
D. Carbon dioxide
Answer: C. Argon
Rationale: Pure argon provides stable arc characteristics, excellent
shielding, and clean welds, making it the preferred shielding gas for
GTAW.
7. Which defect is characterized by small gas pockets trapped in the
weld?
A. Cracking
B. Porosity
C. Undercut
D. Overlap
Answer: B. Porosity
