CWB Welding Inspector Level 3 Exam Prep Question
Bank (Latest 2026/2027 Edition) – Questions, Answers
& Detailed Rationales
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SECTION 1: WELDING PROCESSES AND PROCEDURES
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Question 1
A welding inspector is reviewing a WPS for a structural steel project. The WPS specifies
SMAW using E7018 electrodes with a maximum heat input of 1.5 kJ/mm. During
production welding, the inspector measures a travel speed of 250 mm/min, voltage of
26 V, and amperage of 180 A. Which action should the inspector take?
A. Accept the weld as the parameters are within typical SMAW ranges
B. Reject the weld and require requalification of the WPS
C. Calculate the heat input and compare it to the WPS limit before making a disposition
D. Increase the travel speed to reduce the heat input automatically
Correct Answer:
C — Calculate the heat input and compare it to the WPS limit before making a
disposition
Rationale:
The inspector must calculate heat input using the formula (voltage × amperage × 60) /
(travel speed × 1000) to verify compliance with the WPS limit of 1.5 kJ/mm. The
calculated value is 1.12 kJ/mm, which is within limits, but the inspector must verify this
calculation before disposition. Acceptance or rejection without calculation is
unprofessional; the inspector cannot unilaterally change parameters.
Question 2
,A fabricator is welding 25 mm thick ASTM A516 Grade 70 steel plates using the SAW
process. The WPS specifies a minimum preheat temperature of 150°C based on AWS
D1.1. The base metal temperature at the start of welding is measured at 125°C. Which
action is most appropriate for the welding inspector?
A. Allow welding to proceed since SAW generates sufficient heat to compensate
B. Stop welding and require preheating to the specified minimum before resuming
C. Reduce the welding current to lower the risk of hydrogen cracking
D. Document the deviation and proceed with 100% radiographic testing
Correct Answer:
B — Stop welding and require preheating to the specified minimum before resuming
Rationale:
Preheat temperature is a critical essential variable in WPS qualification; welding below
the specified minimum increases the risk of hydrogen-induced cracking, especially in
thicker sections of carbon-manganese steels. SAW heat generation does not substitute
for preheat; reducing current increases cooling rate; NDT does not prevent cracking.
Question 3
A welding inspector observes that a welder is using a weaving technique with GTAW on
a 6 mm thick stainless steel pipe joint. The WPS specifies stringer beads with a
maximum weave width of 2.5 times the electrode diameter. Which consequence is most
likely if this deviation is allowed to continue?
A. Improved penetration and fusion in the root pass
B. Increased risk of lack of fusion and excessive heat input
C. Reduced distortion due to lower heat concentration
D. Enhanced corrosion resistance in the heat-affected zone
Correct Answer:
B — Increased risk of lack of fusion and excessive heat input
,Rationale:
Excessive weaving in GTAW increases heat input and can cause the weld pool to run
ahead of the arc, resulting in lack of fusion at the toes of the weld. Stringer beads
provide controlled heat input and better fusion. Weaving does not improve penetration
in thin sections; distortion increases with heat input; corrosion resistance is unaffected
by weave pattern.
Question 4
A welding inspector is evaluating a GMAW short-circuiting transfer procedure for 3 mm
thick mild steel. The WPS specifies 100% CO2 shielding gas. The welder requests to
change to 90% Ar / 10% CO2 to improve arc stability. Which action should the inspector
take?
A. Approve the change since argon mixtures generally improve weld quality
B. Reject the change and require adherence to the qualified WPS
C. Allow the change for non-critical welds only
D. Require a new PQR and WPS qualification before implementing the change
Correct Answer:
D — Require a new PQR and WPS qualification before implementing the change
Rationale:
Shielding gas composition is an essential variable in WPS qualification under most
codes (AWS D1.1, ASME IX); changing from 100% CO2 to argon-CO2 mixture alters heat
input, penetration profile, and metallurgical characteristics, requiring requalification. The
inspector cannot approve unilateral changes or make exceptions based on perceived
quality improvements.
Question 5
A welding inspector is reviewing a PQR for a FCAW-G procedure. The PQR was welded
with E71T-1C electrode in the 1G position on 12 mm plate. The fabricator wants to use
, this PQR to support a WPS for 2G position on 20 mm plate. Which code provision
governs this essential variable change?
A. Position is non-essential; thickness is essential and requires requalification
B. Both position and thickness are non-essential variables
C. Position is essential for procedure qualification; thickness over 38 mm is essential
D. Both position and thickness are essential variables requiring new qualification
Correct Answer:
C — Position is essential for procedure qualification; thickness over 38 mm is essential
Rationale:
Under AWS D1.1 and ASME IX, welding position is an essential variable for procedure
qualification (1G does not qualify 2G). Base metal thickness is essential when the
qualified thickness is exceeded by more than the code-allowed range (typically 1.1× for
ASME IX, or specific ranges in AWS D1.1). Since 20 mm is within typical qualification
ranges from 12 mm, thickness may not require requalification, but position does.
Question 6
A welding inspector observes that a welder is using a back gouging technique on a
double-V groove weld in 40 mm thick plate. The back gouge reveals scattered porosity
in the root pass. Which is the most likely cause of this discontinuity?
A. Excessive preheat temperature causing nitrogen absorption
B. Inadequate cleaning of the root pass before back gouging
C. Excessive interpass temperature promoting hydrogen diffusion
D. Insufficient shielding gas flow rate during the root pass
Correct Answer:
B — Inadequate cleaning of the root pass before back gouging
Rationale:
Bank (Latest 2026/2027 Edition) – Questions, Answers
& Detailed Rationales
──────────────────────────────
SECTION 1: WELDING PROCESSES AND PROCEDURES
──────────────────────────────
Question 1
A welding inspector is reviewing a WPS for a structural steel project. The WPS specifies
SMAW using E7018 electrodes with a maximum heat input of 1.5 kJ/mm. During
production welding, the inspector measures a travel speed of 250 mm/min, voltage of
26 V, and amperage of 180 A. Which action should the inspector take?
A. Accept the weld as the parameters are within typical SMAW ranges
B. Reject the weld and require requalification of the WPS
C. Calculate the heat input and compare it to the WPS limit before making a disposition
D. Increase the travel speed to reduce the heat input automatically
Correct Answer:
C — Calculate the heat input and compare it to the WPS limit before making a
disposition
Rationale:
The inspector must calculate heat input using the formula (voltage × amperage × 60) /
(travel speed × 1000) to verify compliance with the WPS limit of 1.5 kJ/mm. The
calculated value is 1.12 kJ/mm, which is within limits, but the inspector must verify this
calculation before disposition. Acceptance or rejection without calculation is
unprofessional; the inspector cannot unilaterally change parameters.
Question 2
,A fabricator is welding 25 mm thick ASTM A516 Grade 70 steel plates using the SAW
process. The WPS specifies a minimum preheat temperature of 150°C based on AWS
D1.1. The base metal temperature at the start of welding is measured at 125°C. Which
action is most appropriate for the welding inspector?
A. Allow welding to proceed since SAW generates sufficient heat to compensate
B. Stop welding and require preheating to the specified minimum before resuming
C. Reduce the welding current to lower the risk of hydrogen cracking
D. Document the deviation and proceed with 100% radiographic testing
Correct Answer:
B — Stop welding and require preheating to the specified minimum before resuming
Rationale:
Preheat temperature is a critical essential variable in WPS qualification; welding below
the specified minimum increases the risk of hydrogen-induced cracking, especially in
thicker sections of carbon-manganese steels. SAW heat generation does not substitute
for preheat; reducing current increases cooling rate; NDT does not prevent cracking.
Question 3
A welding inspector observes that a welder is using a weaving technique with GTAW on
a 6 mm thick stainless steel pipe joint. The WPS specifies stringer beads with a
maximum weave width of 2.5 times the electrode diameter. Which consequence is most
likely if this deviation is allowed to continue?
A. Improved penetration and fusion in the root pass
B. Increased risk of lack of fusion and excessive heat input
C. Reduced distortion due to lower heat concentration
D. Enhanced corrosion resistance in the heat-affected zone
Correct Answer:
B — Increased risk of lack of fusion and excessive heat input
,Rationale:
Excessive weaving in GTAW increases heat input and can cause the weld pool to run
ahead of the arc, resulting in lack of fusion at the toes of the weld. Stringer beads
provide controlled heat input and better fusion. Weaving does not improve penetration
in thin sections; distortion increases with heat input; corrosion resistance is unaffected
by weave pattern.
Question 4
A welding inspector is evaluating a GMAW short-circuiting transfer procedure for 3 mm
thick mild steel. The WPS specifies 100% CO2 shielding gas. The welder requests to
change to 90% Ar / 10% CO2 to improve arc stability. Which action should the inspector
take?
A. Approve the change since argon mixtures generally improve weld quality
B. Reject the change and require adherence to the qualified WPS
C. Allow the change for non-critical welds only
D. Require a new PQR and WPS qualification before implementing the change
Correct Answer:
D — Require a new PQR and WPS qualification before implementing the change
Rationale:
Shielding gas composition is an essential variable in WPS qualification under most
codes (AWS D1.1, ASME IX); changing from 100% CO2 to argon-CO2 mixture alters heat
input, penetration profile, and metallurgical characteristics, requiring requalification. The
inspector cannot approve unilateral changes or make exceptions based on perceived
quality improvements.
Question 5
A welding inspector is reviewing a PQR for a FCAW-G procedure. The PQR was welded
with E71T-1C electrode in the 1G position on 12 mm plate. The fabricator wants to use
, this PQR to support a WPS for 2G position on 20 mm plate. Which code provision
governs this essential variable change?
A. Position is non-essential; thickness is essential and requires requalification
B. Both position and thickness are non-essential variables
C. Position is essential for procedure qualification; thickness over 38 mm is essential
D. Both position and thickness are essential variables requiring new qualification
Correct Answer:
C — Position is essential for procedure qualification; thickness over 38 mm is essential
Rationale:
Under AWS D1.1 and ASME IX, welding position is an essential variable for procedure
qualification (1G does not qualify 2G). Base metal thickness is essential when the
qualified thickness is exceeded by more than the code-allowed range (typically 1.1× for
ASME IX, or specific ranges in AWS D1.1). Since 20 mm is within typical qualification
ranges from 12 mm, thickness may not require requalification, but position does.
Question 6
A welding inspector observes that a welder is using a back gouging technique on a
double-V groove weld in 40 mm thick plate. The back gouge reveals scattered porosity
in the root pass. Which is the most likely cause of this discontinuity?
A. Excessive preheat temperature causing nitrogen absorption
B. Inadequate cleaning of the root pass before back gouging
C. Excessive interpass temperature promoting hydrogen diffusion
D. Insufficient shielding gas flow rate during the root pass
Correct Answer:
B — Inadequate cleaning of the root pass before back gouging
Rationale:
