CRI Welding Defects Identification 3 — Questions and Answers
Question 1: Slag inclusions in a radiograph typically appear as:
- Circular, well-defined dark spots
- Irregular dark indications with jagged edges (Correct answer)
- Bright white angular shapes
- Uniform dark lines parallel to the weld axis
Correct answer: Irregular dark indications with jagged edges
Slag inclusions appear as irregular, dark, jagged indications because slag is less dense than the surrounding weld metal and has an irregular shape.
Question 2: Which parameter most directly affects the sensitivity of a radiograph for detecting small defects?
- Source-to-film distance (SFD)
- Radiation energy (kV or MeV) (Correct answer)
- Film processing temperature
- Image quality indicator (IQI) placement side
Correct answer: Radiation energy (kV or MeV)
Radiation energy determines the contrast and penetration capability, directly influencing the sensitivity to detect small density differences from defects.
Question 3: On a radiograph, incomplete root penetration appears as:
- A continuous dark line along the centerline of the weld root (Correct answer)
- Random dark spots near the weld cap
- A light region at the weld center
- Branching dark lines across the weld width
Correct answer: A continuous dark line along the centerline of the weld root
Incomplete root penetration creates a void at the root centerline, showing as a continuous dark line in the center of the weld image.
Question 4: What does an elongated indication aligned perpendicular to the weld axis most likely represent?
- Transverse crack (Correct answer)
- Longitudinal porosity
- Undercut
- Incomplete fusion at the fusion line
Correct answer: Transverse crack
Transverse cracks run perpendicular to the weld axis and appear as dark elongated lines crossing the weld width.
Question 5: A 'burn-through' in a weld radiograph will typically appear as:
- A very dark circular or irregular area where excess metal melted through (Correct answer)
- A light spot indicating extra weld reinforcement
- A series of fine parallel dark lines
- An absence of any image in the exposed area
Correct answer: A very dark circular or irregular area where excess metal melted through
Burn-through creates a hole or collapsed region in the weld, producing a very dark (high-density) area on the radiograph.
Question 6: Why are image quality indicators (IQIs/penetrameters) placed on the source side of the test object during radiography?
- To reduce exposure time
- To provide the worst-case (least sharp) image for quality assessment (Correct answer)
- To protect the film from scatter radiation
- To measure the total thickness of the weld
Correct answer: To provide the worst-case (least sharp) image for quality assessment
Placing IQIs on the source side produces the least sharp image of the IQI, providing a conservative (worst-case) measure of radiographic sensitivity.
Question 7: Which type of porosity is characterized by a cluster of small rounded dark indications grouped in a limited area of the weld?
- Linear porosity
- Cluster porosity (Correct answer)
- Piping porosity
- Uniformly distributed porosity
Correct answer: Cluster porosity
Cluster porosity consists of multiple small, rounded pores grouped closely together in a localized weld zone.
CRI Welding Defects Identification 3
Slag inclusions in a radiograph typically appear as: