CWI Destructive Testing and Properties 2 — Questions and Answers
Question 1: In a Charpy V-notch impact test, what does the absorbed energy value primarily indicate?
- Tensile strength of the weld metal
- Toughness or notch ductility of the material (Correct answer)
- Hardness of the heat-affected zone
- Yield strength at elevated temperature
Correct answer: Toughness or notch ductility of the material
The Charpy V-notch test measures the energy absorbed during fracture, which is a direct measure of toughness or notch ductility.
Question 2: Which destructive test is specifically designed to evaluate the ductility of a weld and its surrounding base metal by bending the specimen?
- Nick-break test
- Guided bend test (Correct answer)
- Macro-etch test
- Tension test
Correct answer: Guided bend test
The guided bend test uses a jig to bend specimens to a specified angle to evaluate weld ductility and soundness.
Question 3: A face bend specimen is bent so that the:
- Root of the weld is in tension
- Face of the weld is in tension (Correct answer)
- Side of the weld is in tension
- Base metal is in tension only
Correct answer: Face of the weld is in tension
In a face bend test, the weld face is placed on the outer (tension) side of the bend.
Question 4: During a nick-break test, what feature is deliberately introduced to initiate fracture?
- A drilled hole at the weld centerline
- Notches sawed into the weld edges (Correct answer)
- A hardness indent at the root
- A thermal score across the HAZ
Correct answer: Notches sawed into the weld edges
Saw-cut notches are made along both edges of the weld bead to ensure fracture occurs through the weld metal.
Question 5: What does a macro-etch test reveal that a visual inspection cannot?
- Surface porosity counts
- Internal weld discontinuities and fusion quality (Correct answer)
- Weld spatter distribution
- Surface undercut depth
Correct answer: Internal weld discontinuities and fusion quality
Macro-etch testing uses acid to reveal internal weld cross-section features including fusion, penetration, and subsurface discontinuities.
Question 6: The Vickers hardness test uses which type of indenter?
- Steel ball
- Diamond pyramid (Correct answer)
- Brale conical diamond
- Tungsten carbide ball
Correct answer: Diamond pyramid
The Vickers test uses a square-based diamond pyramid indenter and measures the diagonal of the resulting impression.
Question 7: In a transverse tensile test of a weld, where must fracture occur for the test to be considered acceptable per most codes?
- In the weld metal only
- In the HAZ only
- Anywhere, as long as UTS meets minimum requirements (Correct answer)
- Only outside the weld zone
Correct answer: Anywhere, as long as UTS meets minimum requirements
Most codes accept transverse tensile fracture anywhere in the specimen as long as the ultimate tensile strength meets the specified minimum.
CWI Destructive Testing and Properties 2
In a Charpy V-notch impact test, what does the absorbed energy value primarily indicate?