CWI Destructive Testing and Properties 3 — Questions and Answers
Question 1: What is the primary purpose of a fillet weld break test?
- Measure fillet weld hardness
- Evaluate root penetration and internal soundness of fillet welds (Correct answer)
- Determine fillet weld tensile strength
- Verify fillet weld leg size
Correct answer: Evaluate root penetration and internal soundness of fillet welds
The fillet weld break test fractures the weld through its throat to expose the root and internal cross-section for visual examination of fusion and discontinuities.
Question 2: Which mechanical property is defined as a material's resistance to permanent deformation under load?
- Toughness
- Ductility
- Yield strength (Correct answer)
- Modulus of elasticity
Correct answer: Yield strength
Yield strength is the stress at which a material begins to deform plastically (permanently).
Question 3: The Rockwell B scale uses a 100 kgf load with which indenter?
- Diamond Brale cone
- 1/16-inch steel ball (Correct answer)
- Diamond pyramid
- 1/8-inch tungsten carbide ball
Correct answer: 1/16-inch steel ball
Rockwell B uses a 1/16-inch diameter steel ball indenter with a 100 kgf major load, suitable for softer materials.
Question 4: An all-weld-metal tension test differs from a transverse weld tension test in that it:
- Measures HAZ strength only
- Tests the mechanical properties of the deposited weld metal alone (Correct answer)
- Includes base metal in the gauge length
- Evaluates root pass strength exclusively
Correct answer: Tests the mechanical properties of the deposited weld metal alone
An all-weld-metal tension test extracts the specimen entirely from deposited weld metal, isolating its mechanical properties.
Question 5: When performing a root bend test on a groove weld, the specimen is bent so the:
- Weld face is in tension
- Weld root is in tension (Correct answer)
- HAZ is in compression
- Weld centerline is in neutral axis
Correct answer: Weld root is in tension
In a root bend test, the root of the weld is positioned on the tension (outer) side of the bend to evaluate root fusion and ductility.
Question 6: Which acid is commonly used in macro-etch testing of carbon and low-alloy steel welds?
- Hydrofluoric acid
- Ammonium persulfate solution
- 10% nitric acid (nital) or hydrochloric acid solution (Correct answer)
- Ferric chloride solution
Correct answer: 10% nitric acid (nital) or hydrochloric acid solution
A 10% nitric acid (nital) solution or diluted hydrochloric acid (1:1 HCl and water) are standard etchants for carbon and low-alloy steel macro specimens.
Question 7: Elongation in a tensile test is a measure of a material's:
- Hardness
- Ductility (Correct answer)
- Toughness
- Fatigue resistance
Correct answer: Ductility
Elongation, expressed as a percentage increase in gauge length after fracture, quantifies the ductility of the material.
CWI Destructive Testing and Properties 3
What is the primary purpose of a fillet weld break test?