CWB Welding Inspector Level 3 Exam Prep | Complete Study Material

CWB Welding Inspector Level 3 Exam
Prep | Complete Study Material


Instructions: This 79-question multiple-choice exam covers all modules of the CWB Welding
Inspector Level 3 certification per CSA W178.2, including welding metallurgy, welding processes,
materials, weld faults, inspection techniques, NDT methods, codes and standards (e.g., W47.1,
W59), quality management, and inspector responsibilities. Each question has four options
(A–D). Select the best answer. Each question is worth 1.27 points (total 100 points). Good luck!



Question 1
In welding metallurgy, what is the primary purpose of post-weld heat treatment (PWHT)?
A. To increase hardness
B. To relieve residual stresses
C. To accelerate cooling

D. To remove oxides

Correct Answer: B

Rationale: PWHT relieves residual stresses from welding to prevent cracking, per CSA W59.
Why correct: Stress relief improves joint integrity. Why distractors are wrong: Hardness (A) is
increased by quenching; accelerated cooling (C) causes brittleness; oxide removal (D) is
pre-weld cleaning.



Question 2
Which welding process uses a non-consumable electrode and inert gas shielding?
A. Shielded Metal Arc Welding (SMAW)
B. Gas Metal Arc Welding (GMAW)
C. Gas Tungsten Arc Welding (GTAW)

D. Flux-Cored Arc Welding (FCAW)

Correct Answer: C

,Rationale: GTAW (TIG) uses a non-consumable tungsten electrode with inert gas (e.g., argon),
per AWS A2.4. Why correct: Ideal for precise welds. Why distractors are wrong: SMAW (A)
uses consumable electrode; GMAW (B) and FCAW (D) use consumable wire.



Question 3
What is the typical carbon content range for low-carbon steel used in welding?
A. 0.05–0.25%
B. 0.25–0.60%
C. 0.60–1.00%

D. >1.00%

Correct Answer: A

Rationale: Low-carbon steel (0.05–0.25% C) has good weldability and ductility, per ASTM A36.
Why correct: Low carbon reduces hardening. Why distractors are wrong: Medium-carbon (B)
is 0.25–0.60%; high-carbon (C) 0.60–1.00%; very high (D) >1.00% is tool steel.



Question 4
A weld shows incomplete fusion. What is the primary cause?
A. Insufficient heat input
B. Excessive travel speed
C. Wrong electrode angle

D. All of the above

Correct Answer: D

Rationale: Incomplete fusion results from low heat, fast travel, or poor technique, per CSA W59.
Why correct: Multiple factors contribute. Why distractors are wrong: Each (A, B, C) is a
cause, so D is comprehensive.



Question 5
Which NDT method uses magnetic fields to detect surface and near-surface defects?
A. Ultrasonic Testing (UT)
B. Radiographic Testing (RT)
C. Magnetic Particle Testing (MT)

D. Liquid Penetrant Testing (PT)

, Correct Answer: C

Rationale: MT detects discontinuities in ferromagnetic materials using magnetic flux leakage,
per ASTM E709. Why correct: Effective for cracks. Why distractors are wrong: UT (A) uses
sound waves; RT (B) X-rays; PT (D) dyes for surface defects.



Question 6
According to CSA W47.1, what is the minimum preheat temperature for welding 50 mm thick
carbon steel?
A. 10°C
B. 50°C
C. 100°C

D. 150°C

Correct Answer: B

Rationale: CSA W47.1 requires 50°C preheat for 50 mm thick carbon steel to prevent cracking.
Why correct: Prevents hydrogen-induced issues. Why distractors are wrong: 10°C (A) is
ambient; 100°C (C) for thicker; 150°C (D) for high-alloy.



Question 7
What is the role of the welding inspector in quality management?
A. Perform welds
B. Verify compliance with WPS
C. Design welding procedures

D. Select materials

Correct Answer: B

Rationale: Inspectors verify adherence to Welding Procedure Specifications (WPS), per CSA
W178.2. Why correct: Ensures quality. Why distractors are wrong: Welding (A), design (C),
and material selection (D) are engineer duties.



Question 8
In GTAW, what gas is most commonly used for aluminum welding?
A. CO2
B. Argon
C. Helium