NDT Nondestructive Testing Methods & Techniques 5

Question 1

What is 'TOFD' (Time-of-Flight Diffraction) primarily used for in boiler weld inspection?

Accepted Answer

Detecting and sizing weld discontinuities using diffracted sound signals from defect tips

Answer

TOFD uses the diffracted signals from the tips of planar weld defects to accurately detect and size through-wall height of discontinuities without requiring amplitude-based evaluation.

Question 2

A boilermaker discovers pitting corrosion on the inside of a boiler shell during a visual inspection. Which supplemental NDT method would best quantify remaining wall thickness at the pitted area?

Accepted Answer

Ultrasonic thickness measurement

Answer

Ultrasonic thickness measurement uses pulse-echo or resonance techniques to precisely measure remaining wall thickness from one side, ideal for quantifying corrosion depth without draining the vessel.

Question 3

In acoustic emission testing (AET) of a pressure vessel during hydrostatic testing, what does a cluster of AE events from a localized area indicate?

Accepted Answer

Active crack growth or significant structural activity at that location

Answer

A cluster of acoustic emission events localized to one area during pressurization indicates active energy release — typically associated with crack growth, deformation, or structural discontinuity activity.

Question 4

What is the minimum required overlap of radiographic film in a panoramic exposure of a cylindrical pressure vessel?

Accepted Answer

Overlap is determined by the applicable code, typically enough to ensure full coverage is documented

Answer

The applicable construction code (e.g., ASME Section V) specifies minimum film overlap requirements to ensure that no weld area is missed between adjacent film placements.

Question 5

When using the dry powder magnetic particle method outdoors in windy conditions, what is the primary concern?

Accepted Answer

Wind disperses the powder, reducing particle concentration at the inspection area and causing false negatives

Answer

Wind scatters dry magnetic particles before they can be attracted to leakage fields over discontinuities, reducing particle density at the inspection area and potentially missing relevant indications.

(NDT) Boilermaker Nondestructive Testing Certification Practice Test

(NDT) Boilermaker Nondestructive Testing Certification Practice Test

NDT Nondestructive Testing Methods & Techniques 5