CWS CWS Weld Inspection & Testing 1 — Questions and Answers
Question 1: Which nondestructive testing (NDT) method uses high-frequency sound waves to detect internal weld discontinuities?
- Magnetic particle testing
- Ultrasonic testing (Correct answer)
- Liquid penetrant testing
- Visual testing
Correct answer: Ultrasonic testing
Ultrasonic testing (UT) transmits high-frequency sound waves into a weld to detect internal flaws such as porosity, cracks, and incomplete fusion.
Question 2: According to AWS D1.1, what is the minimum preheat temperature required for ASTM A36 steel greater than 1.5 inches thick?
- 32°F (0°C)
- 150°F (66°C) (Correct answer)
- 225°F (107°C)
- 300°F (149°C)
Correct answer: 150°F (66°C)
AWS D1.1 requires a minimum preheat of 150°F for A36 steel over 1.5 inches thick to prevent hydrogen-induced cracking.
Question 3: A CWS notices undercut along the toe of a fillet weld. What is the most common cause of this discontinuity?
- Excessive travel speed (Correct answer)
- Too slow travel speed
- Insufficient shielding gas
- Low amperage
Correct answer: Excessive travel speed
Excessive travel speed causes the weld pool to lag, producing undercut at the weld toe as the arc erodes base metal without sufficient fill.
Question 4: Which weld discontinuity is characterized by a fold of metal that has been rolled or forged into the surface but is not fused to the base metal?
- Porosity
- Undercut
- Lap
- Overlap (Correct answer)
Correct answer: Overlap
Overlap is a protrusion of weld metal beyond the weld toe, lying on the base metal without fusing to it.
Question 5: When performing a macro examination of a weld cross-section, which etchant is most commonly used for carbon steel welds?
- Nital (nitric acid in alcohol) (Correct answer)
- Ferric chloride
- Ammonium persulfate
- Hydrochloric acid
Correct answer: Nital (nitric acid in alcohol)
Nital (2–5% nitric acid in ethanol) is the standard etchant for revealing weld macro structure, HAZ boundaries, and fusion lines in carbon steel.
Question 6: A radiographic test report shows a 2T indication in a groove weld. What does '2T' refer to?
- Two times the throat size
- Two times the material thickness (Correct answer)
- A defect classified as Type 2
- A tensile strength of 2,000 psi
Correct answer: Two times the material thickness
In radiographic testing, 'T' refers to material thickness, so 2T indicates a discontinuity length equal to twice the nominal material thickness.
CWS CWS Weld Inspection & Testing 1
Which nondestructive testing (NDT) method uses high-frequency sound waves to detect internal weld discontinuities?