Pipe Welding Certification SMAW Pipe
6G Performance 100 Questions And
Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A Instant
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1. What is the primary purpose of the root pass in a 6G pipe weld?
A. To provide a decorative surface finish
B. To establish complete penetration and joint integrity at the root
C. To increase electrode consumption
D. To eliminate the need for fill passes
Correct Answer: B. To establish complete penetration and joint integrity at
the root
Rationale: The root pass is the first weld metal deposited and is the
foundation of the entire joint. It must achieve adequate penetration and
fusion at the root to ensure structural integrity; cosmetic appearance is
secondary.
2. In the 6G position, how is the pipe fixed?
A. Horizontal with unrestricted rotation
B. Vertical with the axis horizontal
C. Inclined at approximately 45 degrees and fixed (no rotation)
D. Flat with the axis vertical
Correct Answer: C. Inclined at approximately 45 degrees and fixed (no
rotation)
Rationale: The 6G position requires the pipe to be fixed at roughly 45 degrees
to the horizontal. The welder cannot rotate the pipe, so the weld must be
,made in all positions around the circumference (flat, horizontal, vertical, and
overhead). This makes 6G one of the most demanding qualification positions.
3. Which electrode is most commonly selected for the root pass of an open-
root carbon steel pipe weld in SMAW?
A. E7018
B. E6010
C. E308L
D. E7024
Correct Answer: B. E6010
Rationale: E6010 is a fast-freeze, deep-penetrating cellulose-coated
electrode. Its forceful arc and limited slag production make it well suited for
open-root pipe welds where root penetration and arc control are critical.
4. Why is E7018 generally not preferred for open-root pipe welding without a
backing?
A. It produces excessive slag
B. It has a shallow penetrating arc and is difficult to control on an open root
C. It cannot be used in the vertical position
D. It requires AC current only
Correct Answer: B. It has a shallow penetrating arc and is difficult to control
on an open root
Rationale: E7018 is a low-hydrogen, basic-coated electrode. It is not designed
for open-root conditions because achieving full penetration without burn-
through is very difficult; E6010 is preferred for its digging arc and better
tolerance of joint variations.
5. What is the primary function of the hot pass in a 6G pipe weld?
A. To improve the external appearance only
B. To cover the root pass, refine the root bead, and reduce the chance of
porosity or incomplete fusion
,C. To replace the fill passes
D. To cool the weld rapidly
Correct Answer: B. To cover the root pass, refine the root bead, and reduce
the chance of porosity or incomplete fusion
Rationale: The hot pass is deposited immediately after the root while the
joint is still warm. It helps fuse out any minor root discontinuities, reduces
porosity, and provides a clean base for the fill passes.
6. Which current polarity is typically recommended for E6010 electrodes?
A. Alternating current (AC)
B. Direct current electrode negative (DCEN)
C. Direct current electrode positive (DCEP)
D. Either AC or DCEN
Correct Answer: C. Direct current electrode positive (DCEP)
Rationale: E6010 is designed to run on DCEP (reverse polarity). DCEP provides
the deep penetration and stable arc characteristics required for root passes
on pipe.
7. What is the purpose of feathering a tack weld before welding over it?
A. To reduce the tack weld strength
B. To allow complete tie-in and fusion when the root bead is welded through
the tack
C. To make the tack easier to remove
D. To increase the root gap
Correct Answer: B. To allow complete tie-in and fusion when the root bead is
welded through the tack
Rationale: Feathering (grinding) the ends of a tack weld creates a gradual
transition that allows the root pass to fuse completely into the tack,
preventing lack of fusion or incomplete penetration at the tack location.
, 8. What is undercut?
A. Weld metal extending beyond the joint on both sides
B. A groove melted into the base metal adjacent to the weld toe that is not
filled with weld metal
C. A crack along the weld centerline
D. Excessive root reinforcement
Correct Answer: B. A groove melted into the base metal adjacent to the weld
toe that is not filled with weld metal
Rationale: Undercut is a depression at the weld toe caused by melting of the
base metal without sufficient filler metal to fill the groove. It reduces the
effective throat thickness and creates a stress concentration.
9. Which of the following is critical for achieving proper root penetration in
SMAW pipe welding?
A. Electrode type, current setting, and travel speed
B. Shielding gas flow rate
C. Electrode colour
D. Pipe paint colour
Correct Answer: A. Electrode type, current setting, and travel speed
Rationale: Root penetration is governed by the electrode’s arc characteristics,
the amperage (current), and how fast the welder travels. SMAW does not use
an external shielding gas, so gas flow is not a variable.
10. What is the recommended root gap for a typical 6G pipe joint?
A. 0.5–1 mm
B. 1–2 mm (approximately 3/64–5/64 in)
C. 3–5 mm
D. 6–8 mm
Correct Answer: B. 1–2 mm (approximately 3/64–5/64 in)
Rationale: A root gap in the range of 1–2 mm allows the root pass to
penetrate fully without excessive burn-through or a gap too tight to achieve
fusion. The exact gap depends on the WPS and pipe size.
6G Performance 100 Questions And
Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A Instant
Download Pdf
1. What is the primary purpose of the root pass in a 6G pipe weld?
A. To provide a decorative surface finish
B. To establish complete penetration and joint integrity at the root
C. To increase electrode consumption
D. To eliminate the need for fill passes
Correct Answer: B. To establish complete penetration and joint integrity at
the root
Rationale: The root pass is the first weld metal deposited and is the
foundation of the entire joint. It must achieve adequate penetration and
fusion at the root to ensure structural integrity; cosmetic appearance is
secondary.
2. In the 6G position, how is the pipe fixed?
A. Horizontal with unrestricted rotation
B. Vertical with the axis horizontal
C. Inclined at approximately 45 degrees and fixed (no rotation)
D. Flat with the axis vertical
Correct Answer: C. Inclined at approximately 45 degrees and fixed (no
rotation)
Rationale: The 6G position requires the pipe to be fixed at roughly 45 degrees
to the horizontal. The welder cannot rotate the pipe, so the weld must be
,made in all positions around the circumference (flat, horizontal, vertical, and
overhead). This makes 6G one of the most demanding qualification positions.
3. Which electrode is most commonly selected for the root pass of an open-
root carbon steel pipe weld in SMAW?
A. E7018
B. E6010
C. E308L
D. E7024
Correct Answer: B. E6010
Rationale: E6010 is a fast-freeze, deep-penetrating cellulose-coated
electrode. Its forceful arc and limited slag production make it well suited for
open-root pipe welds where root penetration and arc control are critical.
4. Why is E7018 generally not preferred for open-root pipe welding without a
backing?
A. It produces excessive slag
B. It has a shallow penetrating arc and is difficult to control on an open root
C. It cannot be used in the vertical position
D. It requires AC current only
Correct Answer: B. It has a shallow penetrating arc and is difficult to control
on an open root
Rationale: E7018 is a low-hydrogen, basic-coated electrode. It is not designed
for open-root conditions because achieving full penetration without burn-
through is very difficult; E6010 is preferred for its digging arc and better
tolerance of joint variations.
5. What is the primary function of the hot pass in a 6G pipe weld?
A. To improve the external appearance only
B. To cover the root pass, refine the root bead, and reduce the chance of
porosity or incomplete fusion
,C. To replace the fill passes
D. To cool the weld rapidly
Correct Answer: B. To cover the root pass, refine the root bead, and reduce
the chance of porosity or incomplete fusion
Rationale: The hot pass is deposited immediately after the root while the
joint is still warm. It helps fuse out any minor root discontinuities, reduces
porosity, and provides a clean base for the fill passes.
6. Which current polarity is typically recommended for E6010 electrodes?
A. Alternating current (AC)
B. Direct current electrode negative (DCEN)
C. Direct current electrode positive (DCEP)
D. Either AC or DCEN
Correct Answer: C. Direct current electrode positive (DCEP)
Rationale: E6010 is designed to run on DCEP (reverse polarity). DCEP provides
the deep penetration and stable arc characteristics required for root passes
on pipe.
7. What is the purpose of feathering a tack weld before welding over it?
A. To reduce the tack weld strength
B. To allow complete tie-in and fusion when the root bead is welded through
the tack
C. To make the tack easier to remove
D. To increase the root gap
Correct Answer: B. To allow complete tie-in and fusion when the root bead is
welded through the tack
Rationale: Feathering (grinding) the ends of a tack weld creates a gradual
transition that allows the root pass to fuse completely into the tack,
preventing lack of fusion or incomplete penetration at the tack location.
, 8. What is undercut?
A. Weld metal extending beyond the joint on both sides
B. A groove melted into the base metal adjacent to the weld toe that is not
filled with weld metal
C. A crack along the weld centerline
D. Excessive root reinforcement
Correct Answer: B. A groove melted into the base metal adjacent to the weld
toe that is not filled with weld metal
Rationale: Undercut is a depression at the weld toe caused by melting of the
base metal without sufficient filler metal to fill the groove. It reduces the
effective throat thickness and creates a stress concentration.
9. Which of the following is critical for achieving proper root penetration in
SMAW pipe welding?
A. Electrode type, current setting, and travel speed
B. Shielding gas flow rate
C. Electrode colour
D. Pipe paint colour
Correct Answer: A. Electrode type, current setting, and travel speed
Rationale: Root penetration is governed by the electrode’s arc characteristics,
the amperage (current), and how fast the welder travels. SMAW does not use
an external shielding gas, so gas flow is not a variable.
10. What is the recommended root gap for a typical 6G pipe joint?
A. 0.5–1 mm
B. 1–2 mm (approximately 3/64–5/64 in)
C. 3–5 mm
D. 6–8 mm
Correct Answer: B. 1–2 mm (approximately 3/64–5/64 in)
Rationale: A root gap in the range of 1–2 mm allows the root pass to
penetrate fully without excessive burn-through or a gap too tight to achieve
fusion. The exact gap depends on the WPS and pipe size.
