API 653 Welding Inspection 2

Question 1

According to API 653, which welding process is most commonly specified for repair welding on aboveground storage tanks?

Accepted Answer

Shielded metal arc welding (SMAW)

Answer

SMAW is the most commonly specified process for tank repair welding due to its versatility and wide applicability per API 653 requirements.

Question 2

When performing weld repairs on a tank shell that contains residual product, what is the MOST critical safety precaution before welding?

Accepted Answer

Gas-free the tank and confirm LEL is below 1%

Answer

Gas-freeing the tank and verifying the lower explosive limit (LEL) is below 1% is the most critical step to prevent explosion before any hot work.

Question 3

What does 'weld reinforcement' refer to in the context of tank shell welds?

Accepted Answer

Weld metal deposited above the base metal surface plane

Answer

Weld reinforcement is the weld metal that extends above the plane of the base metal surfaces on a groove weld.

Question 4

Per API 653, what is the minimum preheat temperature required for welding P-1 carbon steel material greater than 1 inch thick?

Accepted Answer

150°F (65°C)

Answer

API 653 referencing ASME Section IX and D1.1 requires a minimum preheat of 150°F for P-1 carbon steel over 1 inch thick to prevent hydrogen cracking.

Question 5

A butt weld joining two shell plates of different thicknesses requires tapering when the thickness difference exceeds what value per API 650?

Accepted Answer

1/16 inch

Answer

When adjoining plates differ in thickness by more than 1/16 inch, the thicker plate must be tapered at a 4:1 slope to provide a smooth transition.

(API 653) API 653 Aboveground Storage Tank Inspector Certification Practice Test