Certified Welder Weld Inspection and Testing Questions and Answers 1 — Questions and Answers
Question 1: An inspector is required to check a carbon steel pipe weld for fine surface and near-surface cracks. Which of the following non-destructive testing (NDT) methods is most suitable for this specific application?
- Liquid Penetrant Testing (PT)
- Radiographic Testing (RT)
- Magnetic Particle Testing (MT) (Correct answer)
- Visual Testing (VT)
Correct answer: Magnetic Particle Testing (MT)
Magnetic Particle Testing (MT) is highly effective for detecting surface and slightly subsurface discontinuities in ferromagnetic materials like carbon steel. It works by creating a magnetic field in the part; discontinuities disrupt this field, attracting magnetic particles to form a visible indication.
Question 2: Which of the following weld discontinuities can be reliably detected using Liquid Penetrant Testing (PT)?
- Incomplete fusion deep within the weld joint
- Slag inclusions located below the surface
- A crack that is open to the surface (Correct answer)
- Internal porosity completely enclosed by weld metal
Correct answer: A crack that is open to the surface
Liquid Penetrant Testing (PT) relies on the principle of capillary action, where a liquid dye is drawn into discontinuities. Therefore, it is only effective for detecting flaws that are open to the surface, such as surface-breaking cracks or porosity. It cannot detect subsurface defects.
Question 3: During a radiographic inspection (RT) of a butt weld, the resulting film shows a localized area that is significantly darker than the surrounding base metal. What does this darker indication most likely represent?
- A region of greater thickness, such as excessive reinforcement
- A dense metallic inclusion, like a tungsten fragment
- A crack aligned perfectly parallel to the radiation beam
- A void, such as porosity or lack of penetration (Correct answer)
Correct answer: A void, such as porosity or lack of penetration
In radiographic testing, areas of lower density or reduced thickness allow more radiation to pass through and expose the film, resulting in a darker image. Voids like porosity, lack of penetration, or slag inclusions are less dense than the solid steel, creating these darker indications.
Question 4: A technician is performing an ultrasonic test (UT) on a thick-section weld. What is the fundamental principle this method uses to identify internal flaws?
- The absorption of X-rays by dense materials
- The reflection of high-frequency sound waves from a discontinuity (Correct answer)
- The disruption of a magnetic field by a crack
- The capillary action of a colored dye into a surface-breaking flaw
Correct answer: The reflection of high-frequency sound waves from a discontinuity
Ultrasonic Testing (UT) uses a transducer to send high-frequency sound waves into the material. When these waves encounter a discontinuity, such as a crack or inclusion, they are reflected back to the transducer. The time it takes for the echo to return indicates the flaw's location and size.
Question 5: Which of the following is a destructive testing method specifically designed to measure the ultimate strength and ductility of a welded joint by pulling it apart?
- Nick-break test
- Bend test
- Tensile test (Correct answer)
- Hardness test
Correct answer: Tensile test
A tensile test is a destructive method where a prepared weld specimen is pulled until it fractures. This test precisely measures the weld's ultimate tensile strength (the maximum stress it can withstand), yield strength, and ductility (% elongation), destroying the sample in the process.
Question 6: According to common industry standards, such as EN ISO 17637, which of the following is a key requirement for performing an effective direct visual inspection of a weld?
- The surface must be coated with a high-contrast paint.
- The inspector's eye must be within 600 mm of the surface and at an angle of not less than 30 degrees. (Correct answer)
- The inspection must be performed under ultraviolet (black) light.
- The weld must be at a minimum temperature of 100°C (212°F) to ensure any moisture has evaporated.
Correct answer: The inspector's eye must be within 600 mm of the surface and at an angle of not less than 30 degrees.
Standards like EN ISO 17637 specify conditions for effective visual testing, including that the inspector's eye should be positioned within 600 mm of the surface at an angle no less than 30 degrees. This ensures a clear and accurate view of the weld surface to identify potential discontinuities.
Certified Welder Weld Inspection and Testing Questions and Answers 1
An inspector is required to check a carbon steel pipe weld for fine surface and near-surface cracks.
Which of the following non-destructive testing (NDT) methods is most suitable for this specific application?