API 510 Material Evaluation and Selection — Questions and Answers
Question 1: Why is material identification important for pressure vessel inspection?
- For inventory purposes only
- To verify the correct material was used and ensure compatibility with service conditions (Correct answer)
- To determine vessel color
- For recycling planning
Correct answer: To verify the correct material was used and ensure compatibility with service conditions
Material identification verifies that construction materials meet specifications and are compatible with the operating environment and contained media.
Question 2: What is positive material identification (PMI)?
- Visual inspection of materials
- Field testing to verify the chemical composition of installed materials (Correct answer)
- Reviewing purchase orders
- Checking paint color
Correct answer: Field testing to verify the chemical composition of installed materials
PMI uses portable analyzers to verify the actual chemical composition of materials, ensuring they match specifications.
Question 3: Which material property is most critical for pressure vessel service at elevated temperatures?
- Color
- Creep resistance and elevated temperature strength (Correct answer)
- Weight
- Magnetic properties
Correct answer: Creep resistance and elevated temperature strength
At elevated temperatures, materials must resist creep deformation and maintain sufficient strength to safely contain pressure.
Question 4: What is hydrogen-induced cracking and why is it a concern for pressure vessels?
- It only affects plastic vessels
- Hydrogen atoms diffuse into steel, causing embrittlement and cracking under stress (Correct answer)
- It is a surface cosmetic issue
- It only occurs in copper
Correct answer: Hydrogen atoms diffuse into steel, causing embrittlement and cracking under stress
Hydrogen atoms can diffuse into steel at high temperatures and pressures, causing embrittlement and cracking that can lead to catastrophic failure.
Question 5: What is the purpose of hardness testing during pressure vessel inspection?
- To determine vessel age
- To assess material condition and detect changes from original properties (Correct answer)
- To measure vessel capacity
- To check paint adhesion
Correct answer: To assess material condition and detect changes from original properties
Hardness testing assesses material condition, detecting changes from heat treatment, service exposure, or welding that could affect mechanical properties.
Question 6: When should material substitutions be evaluated during pressure vessel repairs?
- Never - exact match required always
- When the original material is unavailable, ensuring the substitute meets or exceeds requirements (Correct answer)
- Only for cosmetic repairs
- Substitutions are always acceptable
Correct answer: When the original material is unavailable, ensuring the substitute meets or exceeds requirements
Material substitutions must be carefully evaluated to ensure the replacement material meets or exceeds all requirements for the service conditions.
API 510 Material Evaluation and Selection
Why is material identification important for pressure vessel inspection?