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Free CWI Practice Questions

10 free, exam-style Certified Welding Inspector (CWI) practice questions with answers and explanations. No signup required. Work through them below, then take the full free CWI practice test to study every exam domain.

Question 1

What is the PRIMARY difference between a discontinuity and a defect?

  1. A discontinuity is always visible; a defect may not be detectable
  2. A discontinuity is always larger in size than a defect
  3. A defect exceeds the code acceptance criteria; a discontinuity may or may not
  4. A discontinuity is natural; a defect is always man-made
Show answer & explanation

Correct answer: C - A defect exceeds the code acceptance criteria; a discontinuity may or may not

Question 2

A welding inspector observes a welder using E6010 electrodes for the root pass on a pipe weld. Which polarity should the welder be using?

  1. AC with high frequency stabilization
  2. DCEN (straight polarity)
  3. DCEP (reverse polarity)
  4. Either DCEN or AC polarity
Show answer & explanation

Correct answer: C - DCEP (reverse polarity)

Question 3

A V-groove weld symbol below the reference line shows '60°' inside the V, '1/8' at the root, and '3/8' to the left. This specifies:

  1. A fillet weld with 3/8 inch legs at 60°
  2. A V-groove with 60° angle, 1/8 inch root opening, and 3/8 inch size
  3. A 60° bevel with 3/8 inch reinforcement
  4. A plug weld 3/8 inch in diameter
Show answer & explanation

Correct answer: B - A V-groove with 60° angle, 1/8 inch root opening, and 3/8 inch size

Question 4

An inspector examining a weld on high-strength low-alloy steel discovers cracks in the HAZ 48 hours after welding was completed. These delayed cracks are MOST likely:

  1. Stress corrosion cracks from environmental exposure
  2. Hydrogen-induced (cold) cracks
  3. Reheat cracking from post-weld heat treatment
  4. Lamellar tearing from through-thickness stresses
Show answer & explanation

Correct answer: B - Hydrogen-induced (cold) cracks

Question 5

During production, the minimum preheat specified on the WPS is 200°F. The inspector measures the plate temperature at 175°F. The inspector should:

  1. Accept it because the temperature difference is within acceptable tolerance limits
  2. Require additional preheating to reach the minimum 200°F before welding continues
  3. Document the deviation and proceed with welding under close supervision
  4. Accept it if the welding procedure allows for temperature variations
Show answer & explanation

Correct answer: B - Require additional preheating to reach the minimum 200°F before welding continues

Question 6

For MT to detect a discontinuity, the discontinuity must be oriented:

  1. Parallel to the magnetic flux lines
  2. Perpendicular (or nearly so) to the magnetic flux lines
  3. At an angle between 30° and 60° to the flux lines
  4. At an oblique angle to avoid flux leakage
Show answer & explanation

Correct answer: B - Perpendicular (or nearly so) to the magnetic flux lines

Question 7

The four factors that must ALL be present simultaneously for hydrogen-induced cracking (cold cracking) to occur are:

  1. Hydrogen, high temperature environment, compressive stress, and austenitic microstructure
  2. Hydrogen, susceptible microstructure (martensite), tensile stress, and low temperature
  3. Oxygen contamination, pearlitic microstructure, shear stress, and elevated temperature conditions
  4. Nitrogen presence, bainitic microstructure, residual stress, and moderate temperature range
Show answer & explanation

Correct answer: B - Hydrogen, susceptible microstructure (martensite), tensile stress, and low temperature

Question 8

A weld specification requires a minimum heat input of 30 kJ/in. A welder is running at 26V, 220A, and 12 in/min. Does the heat input meet the minimum?

  1. Yes - HI = 34.3 kJ/in, which exceeds 30 kJ/in
  2. Yes - HI = 28.6 kJ/in, which exceeds 30 kJ/in
  3. No - HI = 28.6 kJ/in, which is below 30 kJ/in
  4. No - HI = 22.0 kJ/in, which is below 30 kJ/in
Show answer & explanation

Correct answer: C - No - HI = 28.6 kJ/in, which is below 30 kJ/in

Question 9

An inspector is evaluating a fillet weld and finds: leg size = 5/16 inch (required 1/4 inch minimum - acceptable), convexity = 3/16 inch (BOS maximum 1/16 inch for this size - rejectable). The overall disposition is:

  1. Accept - leg size is adequate
  2. Reject - convexity exceeds BOS limit
  3. Accept - only one criterion needs to pass
  4. Request engineering evaluation
Show answer & explanation

Correct answer: B - Reject - convexity exceeds BOS limit

Question 10

Per AWS D1.1, a fillet weld is specified as 5/16 inch. The inspector measures the actual weld and finds the leg size is 1/4 inch (undersized by 1/16 inch) over a 3-inch length of a 30-inch total weld length. Per Table 8.1, undersizing up to 1/16 inch is permitted if it does not exceed 10% of the weld length. 10% of 30 inches = 3 inches. This weld is:

  1. Rejectable - undersized welds require engineering approval regardless of length
  2. Acceptable - the undersized portion (3 inches) equals the 10% allowance (3 inches)
  3. Rejectable - undersizing tolerance applies only to intermittent welds, not continuous welds
  4. Rejectable - visual inspection is insufficient for determining undersize acceptance criteria
Show answer & explanation

Correct answer: B - Acceptable - the undersized portion (3 inches) equals the 10% allowance (3 inches)

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