API 510 Non-Destructive Examination Methods 3

Question 1

When conducting liquid penetrant testing on an austenitic stainless steel pressure vessel, which penetrant type is preferred to avoid stress corrosion cracking?

Accepted Answer

Water-washable fluorescent penetrant with low halogen and sulfur content

Answer

For austenitic stainless steel, penetrant materials must have low halogen (chloride) and sulfur content because these contaminants can cause stress corrosion cracking in sensitized austenitic alloys.

Question 2

In radiographic examination, what is geometric unsharpness (Ug) primarily controlled by?

Accepted Answer

Source size, source-to-object distance, and object-to-film distance

Answer

Geometric unsharpness is a function of the radiation source size (focal spot), the source-to-object distance (SOD), and the object-to-film distance (OFD), as defined by Ug = (f × OFD) / SOD.

Question 3

What NDE limitation does API 510 specifically address when evaluating corrosion under insulation (CUI) on pressure vessels?

Accepted Answer

Pulsed eddy current and profile RT can detect CUI through insulation without full removal

Answer

API 510 recognizes that pulsed eddy current (PEC) and profile radiography can screen for CUI through insulation, reducing the need for costly full insulation removal.

Question 4

During straight-beam ultrasonic thickness measurement of a pressure vessel wall, the inspector notices the digital readout fluctuates significantly on a corroded surface. What is the best corrective action?

Accepted Answer

Accept the lowest reading as the minimum thickness

Answer

Per API 510 and ASME inspection practice, when thickness readings fluctuate due to surface irregularity, the lowest recorded reading should be used for fitness-for-service evaluation as it represents the minimum remaining wall.

Question 5

What is the primary purpose of the IQI (image quality indicator) or penetrameter in radiographic testing?

Accepted Answer

To demonstrate that the radiograph has the required sensitivity to detect relevant defects

Answer

The IQI (penetrameter) demonstrates that the radiographic technique has sufficient sensitivity to detect discontinuities of a defined size, serving as a quality indicator for the radiographic process — not as a measurement tool.

(API 510) Certified Pressure Vessel Inspector Practice Test

(API 510) Certified Pressure Vessel Inspector Practice Test

API 510 Non-Destructive Examination Methods 3