Length of root tacks to be placed in 6-inch pipe?

Length of root tacks to be placed in 6-inch pipe?

• A. 1/2 inch to 3/4 inch
• B. 1 inch to 1-1/4 inch
• C. 1/4 inch to 1/2 inch
• D. 3/4 inch to 1 inch

Answer: (A)

Root tacks are small welds used to hold the pipe sections in alignment before the full root weld is laid. For a 6-inch pipe, tack length in the range of about 1/2 inch to 3/4 inch provides the best balance: long enough to securely lock the joint in place, but short enough to limit heat input and reduce the risk of distortion or burn-through at the roots. This size helps keep the joint stable as you begin the root weld and makes inspection and subsequent welding easier. If tacks are too short, they may fail or pop loose under heat; if they’re too long, they introduce unnecessary heat, increasing distortion and cleanup work. Placing several evenly spaced tacks around the circumference secures alignment without overdoing the welds.

Root tacks are small welds used to hold the pipe sections in alignment before the full root weld is laid. For a 6-inch pipe, tack length in the range of about 1/2 inch to 3/4 inch provides the best balance: long enough to securely lock the joint in place, but short enough to limit heat input and reduce the risk of distortion or burn-through at the roots. This size helps keep the joint stable as you begin the root weld and makes inspection and subsequent welding easier. If tacks are too short, they may fail or pop loose under heat; if they’re too long, they introduce unnecessary heat, increasing distortion and cleanup work. Placing several evenly spaced tacks around the circumference secures alignment without overdoing the welds.