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CWI Destructive Tests practice questions

Tension, bend, Charpy impact, hardness, macroetch, nick-break and fillet-break tests and what each one tells you. This domain is about 4% of the exam. Try each question, then open the answer.

Read the Destructive Tests study guide

Question 1

In a root bend test of a groove weld, which surface is placed in tension?
  1. The root surface of the weld
  2. The weld face
  3. A cross-section through the thickness
  4. Neither, because the specimen is compressed
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Answer: A. The root surface of the weld

In a root bend, the specimen is bent so the root side is on the outside of the bend, in tension. This exposes root defects such as incomplete penetration or root fusion problems.

Source: AWS B4.0, Standard Methods for Mechanical Testing of Welds (face, root and side bends)

Question 2

What property does a Charpy V-notch test measure?
  1. Hardness of the notch root measured by rebound
  2. Yield strength at the test temperature
  3. Fatigue life under repeated loading
  4. Notch toughness, as absorbed impact energy
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Answer: D. Notch toughness, as absorbed impact energy

A pendulum breaks a notched specimen at a set temperature and the absorbed energy is reported in ft-lbf or joules. Lateral expansion and percent shear fracture may also be reported. Toughness of steel drops sharply below its transition temperature.

Source: AWS B4.0, Standard Methods for Mechanical Testing of Welds (Charpy impact tests)

Question 3

A broken steel test specimen shows a bright, granular fracture surface with little deformation. What type of fracture is this?
  1. Ductile fracture
  2. Fatigue fracture
  3. Shear lip fracture
  4. Brittle fracture
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Answer: D. Brittle fracture

Brittle fracture absorbs little energy and leaves a bright, crystalline or granular surface with little deformation. Ductile fracture leaves a dull, fibrous surface with necking or shear lips.

Source: AWS Welding Inspection Handbook, 4th ed., chapter on destructive testing; AWS B4.0, Standard Methods for Mechanical Testing of Welds

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