SCWI Examination Practice Questions

AWS Senior Certified Welding Inspector (SCWI) Examination Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary purpose of preheating a weldment?
• To improve surface finish
• To reduce the risk of cracking
• To speed up cooling
• To increase weld metal hardness

Rationale: Preheating reduces thermal gradients in the base metal,

minimizing the risk of hydrogen-induced cracking.

• Which type of weld joint is characterized by two members placed edge

to edge?

• Butt joint 1 / 4

• Lap joint
• Corner joint
• Edge joint

Rationale: Edge joints involve two members placed side by side with

their edges parallel, typically used for thin sheets.

3. The most common welding process for structural steel is:

• Gas tungsten arc welding (GTAW)
• Shielded metal arc welding (SMAW)
• Flux-cored arc welding (FCAW)
• Oxy-fuel welding (OFW)

Rationale: FCAW provides deep penetration and high deposition rates,

making it common for structural steel applications.

• Which discontinuity is most often associated with rapid cooling of

weld metal?

• Porosity
• Cracking
• Undercut
• Slag inclusion

Rationale: Rapid cooling can produce high residual stresses, which can

lead to cracking in the weld or HAZ.

• What is the primary advantage of using low-hydrogen electrodes in

SMAW?

• Lower deposition rate 2 / 4

• Reduced risk of hydrogen-induced cracking
• Increased weld bead appearance
• Faster welding speed

Rationale: Low-hydrogen electrodes minimize the introduction of

hydrogen into the weld metal, reducing the risk of cracking.

• Which NDT method is most suitable for detecting surface-breaking

cracks?

• Radiographic testing (RT)
• Ultrasonic testing (UT)
• Magnetic particle testing (MT)
• Liquid penetrant testing (PT)

Rationale: PT is highly effective for identifying surface discontinuities in

non-porous materials.

• Which of the following is a common cause of incomplete fusion in a

weld?

• High amperage
• Low heat input
• Proper electrode angle
• Adequate cleaning of base metal

Rationale: Insufficient heat prevents proper melting and fusion of the

base metal and filler metal.

8. The heat-affected zone (HAZ) is:

• The melted portion of the weld 3 / 4

• The base metal far from the weld
• The filler metal only
• The base metal adjacent to the weld that experienced thermal

cycles

Rationale: The HAZ undergoes microstructural changes due to heat but

does not melt.

• What is the purpose of post-weld heat treatment (PWHT)?
• To increase weld deposition rate
• To relieve residual stresses and reduce hardness
• To clean slag
• To prevent porosity

Rationale: PWHT reduces residual stress and potential cracking in the

weld and HAZ.

• Which factor is most likely to cause porosity in a weld?
• Incorrect electrode angle
• Contaminated base metal or filler metal
• Slow welding speed
• Proper shielding gas

Rationale: Contamination introduces gases that cannot escape,

forming porosity.

• In ultrasonic testing, what indicates a discontinuity?
• A change in color
• A reflected or backscattered signal
• / 4