Pipefitter Pipe Fabrication Methods 2

Question 1

When making a 90-degree offset using two 45-degree elbows, what is the travel distance if the offset is 18 inches?

Accepted Answer

25.46 inches

Answer

18.00 inches

Answer

21.97 inches

Answer

12.73 inches

Question 2

What is the correct process for post-weld heat treatment (PWHT) of a carbon steel weld to reduce residual stress?

Accepted Answer

Heat the weldment uniformly to 1100 to 1200 degrees F (593 to 649 C) and hold for a specified time, then cool slowly

Answer

Cool rapidly with water after welding

Answer

Apply preheat to 400 degrees F and immediately cool in still air

Answer

Heat to 1500 degrees F and quench in oil

Question 3

What is the minimum preheat temperature required by ASME B31.3 for welding carbon steel pipe with a wall thickness greater than 1 inch?

Accepted Answer

175 degrees F (79 C)

Answer

50 degrees F (10 C)

Answer

300 degrees F (149 C)

Answer

400 degrees F (204 C)

Question 4

What is the purpose of back-purging with argon gas when TIG welding stainless steel pipe?

Accepted Answer

To prevent oxidation (sugaring) on the pipe ID weld root, maintaining corrosion resistance

Answer

To cool the weld faster and reduce distortion

Answer

To increase weld penetration depth

Answer

To pre-heat the base metal evenly before welding

Question 5

When using a pipe wrap-around to mark a cutline on a pipe, what is the tool ensuring?

Accepted Answer

The cut line is perfectly perpendicular (square) to the pipe axis

Answer

The mark is at the correct elevation for installation

Answer

The mark matches the isometric drawing pipe length

Answer

The mark locates the weld centerline for NDE inspection

Question 6

What type of pipe joint is best suited for connecting dissimilar metals to prevent galvanic corrosion in a piping system?

Accepted Answer

Dielectric union or insulating flange kit

Answer

Butt weld joint

Answer

Threaded coupling

Answer

Socket weld coupling