CWI Ultimate Review 4 — Questions and Answers
Question 1: Which electrode classification is considered a low-hydrogen electrode?
- E6010
- E6013
- E7018 (Correct answer)
- E6011
Correct answer: E7018
E7018 is a low-hydrogen electrode (indicated by the '8' suffix) requiring moisture-controlled storage and often preheating to prevent hydrogen-induced cracking.
Question 2: A CWI finds a crack in a completed structural weld. What is the FIRST action the inspector should take?
- Immediately notify the owner and stop all welding on the project
- Document and report the discontinuity to the responsible party per project procedures (Correct answer)
- Grind out and repair the crack personally
- Accept the crack if it is shorter than the code-allowable limit
Correct answer: Document and report the discontinuity to the responsible party per project procedures
The CWI's primary role is to document and report discontinuities to the responsible party; the inspector does not typically direct repairs or make acceptance decisions unilaterally.
Question 3: What is the correct technique for measuring the throat of a fillet weld with a fillet weld gauge?
- Place the gauge against the weld face and read the throat dimension directly
- Measure the leg length and calculate the theoretical throat as 0.707 × leg (Correct answer)
- Place the gauge in the weld root and measure to the weld face
- Measure the width of the weld bead at the surface
Correct answer: Measure the leg length and calculate the theoretical throat as 0.707 × leg
The theoretical throat of an equal-leg fillet weld is calculated as 0.707 times the leg length, which is what fillet weld gauges based on leg length reflect.
Question 4: Lamellar tearing in a weld joint is most likely to occur in:
- Vertical butt joints in thin plate
- T-joints or corner joints with high restraint and through-thickness stress (Correct answer)
- Single-pass overhead fillet welds
- Root passes of open-root pipe welds
Correct answer: T-joints or corner joints with high restraint and through-thickness stress
Lamellar tearing occurs in the base metal of highly restrained T-joints and corner joints due to through-thickness tensile stresses on material with poor through-thickness ductility (low reduction of area).
Question 5: On a welding procedure specification (WPS), which of the following is an ESSENTIAL variable for SMAW per AWS D1.1?
- Change in post-weld heat treatment (PWHT) when not originally required (Correct answer)
- Change in travel angle by more than 5°
- Change in electrode diameter within the same F-number
- Change in base metal surface preparation method
Correct answer: Change in post-weld heat treatment (PWHT) when not originally required
Addition of PWHT when it was not part of the original qualified procedure is an essential variable requiring requalification for SMAW per AWS D1.1.
Question 6: The purpose of interpass temperature control during multi-pass welding is to:
- Speed up the welding process
- Prevent excessive grain growth in the HAZ and maintain mechanical properties (Correct answer)
- Increase penetration in subsequent passes
- Reduce the need for post-weld cleaning
Correct answer: Prevent excessive grain growth in the HAZ and maintain mechanical properties
Controlling maximum interpass temperature prevents excessive grain coarsening in the heat-affected zone, which would degrade toughness and mechanical properties.
Question 7: Which destructive test is used to determine the tensile strength of a weld joint transverse to the weld axis?
- Nick-break test
- Reduced-section tensile test (Correct answer)
- Free-bend test
- Fillet weld break test
Correct answer: Reduced-section tensile test
The reduced-section tensile test pulls a specimen transversely across the weld joint to measure ultimate tensile strength of the weld and adjacent base metal.
CWI Ultimate Review 4
Which electrode classification is considered a low-hydrogen electrode?