API 510 Material Evaluation 4

Question 1

A 316L stainless steel vessel is suspected of sensitization from an improper heat treatment. Which nondestructive test can detect chromium carbide precipitation at grain boundaries?

Accepted Answer

Electrochemical potentiokinetic reactivation (EPR) testing

Answer

EPR testing is an electrochemical NDE method specifically designed to detect sensitization in austenitic stainless steels by measuring chromium depletion at grain boundaries.

Question 2

When reviewing material specifications for a vessel repair, an inspector notes the replacement plate is SA-516-70 and the existing vessel shell is SA-285-C. What is the primary concern with this material combination?

Accepted Answer

Mismatch in tensile strength affecting weld joint efficiency calculations

Answer

SA-516-70 (70 ksi tensile) and SA-285-C (55 ksi tensile) have different strength levels, requiring the engineer to base joint efficiency calculations on the weaker material.

Question 3

A vessel in amine service develops cracking that is confirmed as amine stress corrosion cracking. Which metallurgical condition of the base metal and welds is the most important risk factor?

Accepted Answer

High residual tensile stresses from fabrication combined with hardness above 200 BHN

Answer

Amine SCC requires tensile stress to propagate; high residual stresses from cold forming or welding combined with elevated hardness significantly increase susceptibility.

Question 4

An inspector identifies a section of vessel wall that has experienced creep damage. Which of the following microstructural features confirms advanced creep damage during metallurgical examination?

Accepted Answer

Creep voids and microfissures along grain boundaries leading to grain boundary cracking

Answer

Advanced creep damage is characterized by creep voids (cavities) forming at grain boundaries that link to form microfissures, ultimately leading to intergranular cracking and failure.

Question 5

A low-alloy steel (2.25Cr-1Mo) vessel has undergone long-term service at 850°F. The inspector is evaluating the material for temper embrittlement. Which test best quantifies the degree of embrittlement?

Accepted Answer

Charpy V-notch impact testing at 32°F vs. baseline impact values

Answer

Charpy V-notch impact testing at a reference temperature compared to original baseline values directly measures the shift in DBTT caused by temper embrittlement.

(API 510) API 510 Inspector Certification Practice Test

(API 510) API 510 Inspector Certification Practice Test

API 510 Material Evaluation 4