Condition in which the weld did not reach the root of a joint designed for complete penetration, leaving the original root faces or gap unfused. Causes include a heavy land, a tight root opening, hi-lo, low current and fast travel. On radiographs it shows as a straight dark line at the weld centerline, and inside pipe it can be seen with a borescope. It is rejectable in CJP joints.
Film shows incomplete penetration right at six, the land was too heavy and the gap too tight.
Also heard as
- IP
- lack of penetration
- LOP
- incomplete joint penetration
Related terms
Root pass
The first weld pass in a joint, laid at the root, which sets the quality of everything above it.
Land
Shop word for the flat root face left at the bottom of a bevel, called the root face in codes.
Hi-lo
Shop name for misalignment between two pipe or plate edges, where one sits higher than the other.
Lack of fusion
Weld metal that failed to fuse with the base metal or a previous pass at some boundary.
CJP
Complete joint penetration: a groove weld that fuses through the full thickness of the joint.