Pipefitter Pipe Fabrication and Joining 2

Question 1

What is the minimum preheat temperature required by AWS D1.1 when welding carbon steel with a carbon equivalent greater than 0.40?

Accepted Answer

150°F (65°C)

Answer

32°F (0°C)

Answer

400°F (205°C)

Answer

75°F (24°C)

Question 2

When making a socket weld joint, what is the standard gap that should be left between the pipe end and the socket bottom?

Accepted Answer

1/16 inch (1.6 mm)

Answer

No gap — pipe must bottom out

Answer

1/4 inch (6.4 mm)

Answer

1/8 inch (3.2 mm)

Question 3

What type of pipe joint is made by heating the end of a pipe and forming a conical seating surface that mates with a flared fitting?

Accepted Answer

A flared joint

Answer

A compression joint

Answer

A mechanical joint

Answer

A press-fit joint

Question 4

What is meant by 'back-purging' during stainless steel pipe welding?

Accepted Answer

Flowing inert gas inside the pipe to protect the weld root from oxidation

Answer

Reversing the welding direction to fill undercut

Answer

Cleaning the weld joint with back-hand motion

Answer

Using back-pressure to prevent weld burn-through

Question 5

In threaded pipe joints per ASME B1.20.1, what is the standard taper of NPT (National Pipe Taper) threads?

Accepted Answer

1/16 inch per inch (1 in 16)

Answer

1/8 inch per inch (1 in 8)

Answer

1/32 inch per inch (1 in 32)

Answer

1/4 inch per inch (1 in 4)

Question 6

What is the primary advantage of a 'butt weld' joint over a 'socket weld' joint for larger pipe sizes?

Accepted Answer

Butt welds provide full penetration with no crevice for corrosion or trapped fluid

Answer

Butt welds are faster and easier to make

Answer

Socket welds are only available up to 2-inch pipe size

Answer

Butt welds do not require post-weld heat treatment