Where are the first 2 tacks placed on a 6" pipe?

Where are the first 2 tacks placed on a 6" pipe?

• A. 12 o'clock and 6 o'clock
• B. 3 o'clock and 9 o'clock
• C. 1 o'clock and 7 o'clock
• D. 2 o'clock and 8 o'clock

Answer: (A)

Tack welds are used to hold the pipe joint in place and keep the alignment true before the full weld is done. For a circular pipe, placing the first two tacks opposite each other on the top and bottom locks the joint and keeps it centered. This opposite placement helps resist distortion and prevents rotation as you weld around the circumference, so the seam stays square and the pipe ends stay flush. Tacking on the sides would bias the joint in a way that allows more movement or rotation when heat is applied, making it harder to maintain proper alignment. So the top and bottom tacks give the most stable, centered fit-up for starting the weld.

Tack welds are used to hold the pipe joint in place and keep the alignment true before the full weld is done. For a circular pipe, placing the first two tacks opposite each other on the top and bottom locks the joint and keeps it centered. This opposite placement helps resist distortion and prevents rotation as you weld around the circumference, so the seam stays square and the pipe ends stay flush.

Tacking on the sides would bias the joint in a way that allows more movement or rotation when heat is applied, making it harder to maintain proper alignment. So the top and bottom tacks give the most stable, centered fit-up for starting the weld.