Pipe Fabrication and Joining Flashcards
7 cards from real PIPEFITTER practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Pipe Fabrication and Joining flashcards as text
When performing a socket weld on a 2-inch pipe, what gap should be left between the pipe end and the socket shoulder before welding?
Answer: 1/16 inch gap to allow for thermal expansion
A 1/16-inch gap is maintained before socket welding to allow for thermal expansion and prevent distortion during the welding process.
Which pipe end preparation is required for a Class 6000 threaded fitting on a high-pressure steam line?
Answer: Standard NPT taper thread with sealant
Class 6000 threaded fittings use NPT (National Pipe Taper) threads with an appropriate high-temperature thread sealant for high-pressure steam service.
A pipefitter needs to cut stainless steel pipe using a portable band saw. What blade characteristic is most important for this material?
Answer: Bi-metal blade with 14-18 TPI
A bi-metal blade with 14-18 teeth per inch provides the right balance of heat resistance and cutting speed for stainless steel without work-hardening the material.
During a hydrostatic pressure test, a threaded joint is found to be weeping. After depressurizing, what is the correct corrective action?
Answer: Disassemble, clean, re-apply sealant, and reassemble
The proper fix is to fully depressurize, disassemble the joint, clean the threads, apply fresh sealant, and reassemble to the correct torque.
What is the primary purpose of a purge dam when welding stainless steel pipe?
Answer: To maintain inert gas backing on the weld root and prevent oxidation
Purge dams are used to isolate the weld zone inside the pipe so an inert backing gas (typically argon) can prevent oxidation of the root bead on stainless steel.
A groove weld on schedule 80 carbon steel pipe requires a root opening of 3/32 inch. Which root opening tool is used to verify this dimension?
Answer: A wire gauge or spacer rod of the correct diameter
A wire gauge or spacer rod of 3/32-inch diameter is inserted into the root opening to verify consistent spacing around the joint before tacking.
When cutting carbon steel pipe with an oxy-fuel torch, the cutting oxygen lever should be opened at which point in the process?
Answer: After the base metal has reached bright cherry-red or orange heat
The cutting oxygen jet is opened only after the steel reaches the ignition temperature (bright cherry-red to orange) so the exothermic oxidation reaction can sustain the cut.