For joining 6" nominal pipe size, how many tacks are recommended?

For joining 6" nominal pipe size, how many tacks are recommended?

• A. 2
• B. 4
• C. 6
• D. 8

Answer: (B)

Tack welds are used to hold the pipe sections in proper alignment and spacing before you complete the weld. For a 6" nominal pipe size, placing four tack welds evenly around the circumference keeps the joint from shifting when heat is applied and helps maintain a uniform root gap as you start the weld. Four tacks, spaced roughly at 90-degree intervals, provide enough restraint to prevent distortion without adding unnecessary heat input or complexity. If you used fewer than four, the joint can move or become misaligned during welding; more tacks aren’t typically needed for this size and can waste time and increase heat exposure.

Tack welds are used to hold the pipe sections in proper alignment and spacing before you complete the weld. For a 6" nominal pipe size, placing four tack welds evenly around the circumference keeps the joint from shifting when heat is applied and helps maintain a uniform root gap as you start the weld. Four tacks, spaced roughly at 90-degree intervals, provide enough restraint to prevent distortion without adding unnecessary heat input or complexity. If you used fewer than four, the joint can move or become misaligned during welding; more tacks aren’t typically needed for this size and can waste time and increase heat exposure.