Pipe Fabrication and Joining Flashcards
6 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 6 Pipe Fabrication and Joining flashcards as text
What is the purpose of a 'weld neck flange' compared to a 'slip-on flange' in high-pressure service?
Answer: Weld neck flanges transfer stress from the flange to the pipe wall, providing superior strength in high-pressure/temperature service
The weld neck flange's tapered hub transfers stress from the flange into the pipe wall, making it superior for high-pressure, high-temperature, and cyclic service.
When preparing a beveled pipe end for butt welding per ASME B31.3, what is the standard bevel angle for a standard V-groove weld joint?
Answer: 37.5 degrees from the pipe axis (30 degrees from the bevel face)
ASME B31.3 specifies a standard bevel angle of 37.5 degrees from the pipe axis (equivalent to a 30-degree bevel from the perpendicular face) for butt weld preparation.
What is the function of 'tack welds' during pipe fabrication?
Answer: To temporarily hold pipe components in alignment until the full weld is completed
Tack welds are temporary welds used to hold pipe components in proper alignment and gap while the full weld is completed.
What is 'interpass temperature control' during pipe welding, and why is it important for stainless steel?
Answer: Limiting the maximum temperature between weld passes to prevent carbide precipitation and corrosion loss in stainless steel
Interpass temperature control limits the maximum temperature between weld passes. For austenitic stainless steel, exceeding 350°F can cause carbide precipitation (sensitization), reducing corrosion resistance.
What is the purpose of post-weld heat treatment (PWHT) on carbon steel pipe welds?
Answer: To relieve residual welding stresses and reduce hardness in the heat-affected zone
PWHT relieves residual stresses locked in during welding and tempers the hard heat-affected zone, reducing the risk of stress corrosion cracking and brittle fracture.
When cutting stainless steel pipe with a grinder or saw, why must the tools be dedicated to stainless steel only?
Answer: Carbon steel particles from shared tools embed in the stainless surface and cause rust contamination
Carbon steel particles from grinding wheels or saw blades used on carbon steel can embed into the stainless steel surface, creating rust spots and compromising corrosion resistance.