Pipe Fabrication Methods 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 Methods flashcards as text
What is the minimum preheat requirement purpose when welding on high-carbon or alloy steel pipe during fabrication?
Answer: To reduce the risk of hydrogen-induced cracking in the heat-affected zone
Preheat slows the cooling rate of the weld and HAZ, reducing the risk of hydrogen-induced (cold) cracking in hardenable steel alloys.
In shop fabrication, what is the primary advantage of using a pipe positioner (turning roll) during welding?
Answer: It keeps the weld in the flat (1G) position throughout the joint
A pipe positioner rotates the pipe so the welder can maintain the flat 1G position, producing higher-quality, faster welds.
Which pipe end preparation is required for a standard butt weld joint on pipe with wall thickness greater than 3/16 inch?
Answer: Beveled end at approximately 37.5 degrees
ASME B31 codes require pipe ends thicker than 3/16 inch to be beveled at approximately 37.5 degrees to allow full penetration groove welds.
What is a 'spool' in the context of pipe fabrication?
Answer: A pre-fabricated pipe assembly consisting of pipe, fittings, and flanges ready for field installation
A spool is a shop-fabricated pipe assembly — a sub-section of piping complete with fittings and flanges — transported to the field for installation.
When using an oxy-fuel torch to cut pipe for fabrication, what is the function of the cutting oxygen lever?
Answer: It releases a high-pressure stream of oxygen that oxidizes and blows away the molten metal
The cutting oxygen lever opens a valve that directs a high-pressure oxygen stream onto the preheated metal, causing rapid oxidation and blowing the slag away.
Which type of pipe flange is typically used as a companion flange on equipment nozzles and allows for slight angular misalignment during assembly?
Answer: Lap joint flange with stub end
A lap joint flange pairs with a stub end and can rotate freely around it, allowing bolt holes to be aligned and accommodating minor angular misalignment.
What does 'center-to-center' (C-C) dimension mean on a piping isometric drawing?
Answer: The distance measured from the center of one fitting or component to the center of another
Center-to-center is the dimension from the centerline intersection of one fitting to the centerline intersection of another, used to lay out piping runs.