Initial pass deposited at the root of a groove weld, fusing both members and, in open-root work, forming the inside surface of the joint. On pipe it is often run with 6010 or GTAW and must show complete penetration without suck-back or icicles. Defects here, such as lack of fusion and incomplete penetration, are the hardest to repair and the most common reason for failed radiographs.
Root pass looks good from the inside, a little crown all the way around, no suck-back at six.
Most pipe repairs trace back to the root, so a welder who puts in a clean root on every joint is worth more than one with a pretty cap.
Also heard as
- root
- root bead
- stringer bead
- first pass
Related terms
Hot pass
The second pass on a pipe weld, run hot and fast right after the root to burn out trapped slag.
Root opening
The gap between members at the root of a joint, set during fit-up before welding.
Land
Shop word for the flat root face left at the bottom of a bevel, called the root face in codes.
Incomplete penetration
A root left unfused because the weld never reached all the way through a joint meant to be fully penetrated.
6010
A deep-digging cellulosic stick rod run on DCEP, the classic choice for open-root pipe passes.