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

Oxyfuel welding (OFW)

Answer

Electron beam welding (EBW)

Answer

Friction stir welding (FSW)

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

Apply a rust-inhibiting primer to the weld area

Answer

Pre-heat the shell to 250°F minimum

Answer

Install sacrificial anodes near the repair area

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

Additional backing bars placed behind the weld

Answer

Post-weld heat treatment applied to strengthen the joint

Answer

A second weld pass overlapping the first

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

50°F (10°C)

Answer

200°F (93°C)

Answer

300°F (149°C)

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

3/16 inch

Answer

1/4 inch

Answer

3/8 inch

Question 6

Which NDE method is best suited for detecting subsurface planar defects (such as lack of fusion) in a tank shell weld?

Accepted Answer

Radiographic testing (RT)

Answer

Magnetic particle testing (MT)

Answer

Liquid penetrant testing (PT)

Answer

Visual testing (VT)

Question 7

When a weld repair procedure requires PWHT and the tank cannot be furnace-heated, what alternative does API 653 permit?

Accepted Answer

Perform local PWHT using resistance or induction heating

Answer

Skip PWHT if material is below 0.5 inch thick

Answer

Substitute increased preheat temperature for PWHT

Answer

Apply a stress-relief coating after welding