In pipe welding, what is the most commonly used groove shape?

• A. Single bevel-groove
• B. V-groove
• C. U-groove
• D. J-groove

Answer: (B)

Understanding how groove shapes affect root access and penetration in pipe welds helps explain why the V-groove is the most commonly used. A V-groove forms a symmetrical opening on both sides of the joint, giving straightforward access for the GTAW heat to reach the root and for subsequent passes to fill and cap evenly. This symmetry makes it predictable to achieve full penetration across a range of wall thicknesses and pipe sizes, with consistent bead shape and fusion.

Because of its geometry, the V-groove works well for many standard piping applications and welding positions, and it balances ease of preparation with good root quality. Other shapes—such as U or J—often require more filler metal to achieve full penetration or are chosen for niche situations where edge retention or specific heat flow is desired. A single bevel-groove is typically used for thinner walls or single-sided welds and doesn’t provide the same symmetric access as a V-groove.