API 510 Inspection Techniques & Nondestructive Testing 4

Question 1

A hydrogen-induced cracking (HIC) inspection of a carbon steel vessel operating in wet H₂S service should prioritize which NDT technique?

Accepted Answer

Straight beam UT or phased array UT to detect internal laminar cracking

Answer

HIC produces internal laminar cracks parallel to the plate surface; straight beam UT effectively detects these by identifying loss of back-wall reflection or anomalous mid-wall indications.

Question 2

Guided wave ultrasonic testing (GWUT) is used in pressure vessel piping inspections primarily to:

Accepted Answer

Screen long lengths of pipe for corrosion anomalies from a single probe position

Answer

GWUT propagates low-frequency waves along the pipe axis, allowing a single probe to screen tens of meters of pipe for corrosion, erosion, or other wall-loss anomalies.

Question 3

When using phased array ultrasonic testing (PAUT) for weld inspection, which advantage does it offer over conventional single-element UT?

Accepted Answer

Provides multiple beam angles simultaneously with electronic scanning

Answer

PAUT electronically steers and focuses multiple beam angles without physically moving the probe, enabling faster scanning and improved flaw characterization compared to single-element UT.

Question 4

During an internal visual inspection of a pressure vessel, the inspector observes a deposit of orange-brown scale on the bottom head. The most likely cause and recommended follow-up is:

Accepted Answer

Iron oxide from general corrosion; perform UT thickness readings under and near the deposit

Answer

Orange-brown scale is typically iron oxide corrosion product; UT should be performed under and around the deposit to quantify metal loss beneath it.

Question 5

What does the term 'remaining life' mean in the context of API 510 inspection planning?

Accepted Answer

The estimated time before the vessel wall reaches minimum allowable thickness at the measured corrosion rate

Answer

Remaining life is calculated by dividing the difference between current thickness and minimum allowable thickness by the corrosion rate, giving the estimated time before retirement.

(API 510) API 510 Inspector Certification Practice Test

(API 510) API 510 Inspector Certification Practice Test

API 510 Inspection Techniques & Nondestructive Testing 4