What condition must the prepared edges of a pipe be in before welding?

• A. Kept dry and oil-free
• B. Be cleaned on one side only
• C. Edges must be grooved, but cleaning is optional
• D. Should be cleaned on both sides to at least an inch and should be appropriately grooved

Answer: (D)

Edge preparation for pipe welding focuses on creating a clean, properly shaped joint that allows full fusion and proper penetration. Contaminants on the mating surfaces—oil, moisture, rust, or oxide—can trap gas or cause porosity and lack of fusion if not removed, so cleaning must cover both sides of the edge, not just one.

Grooving or beveling the edges provides the necessary groove geometry for the weld to fill and for root fusion to occur reliably. Without a groove, the weld may not reach the root properly, leading to weak penetration or incomplete joint fusion. Cleaning to at least an inch on both sides ensures the cleaned surface extends into the bevel area, giving a clean, robust base for the root and subsequent passes and helping prevent recontamination during weld deposition.

So, the prepared edges should be cleaned on both sides to at least an inch and should be appropriately grooved. This combination addresses cleanliness and joint geometry to promote sound, penetration-friendly TIG root passes.