How deep the melted zone reaches below the base metal surface or into the joint. Process, current, polarity, gas, travel speed and electrode angle all change it: 6010 and spray transfer dig deep, while short-circuit GMAW is shallow. Joint penetration, how far the weld reaches through the joint thickness, is what CJP and PJP describe and what radiographs check at the root.
Macro shows penetration barely past the root face, turn up the amps or open the gap.
Also heard as
- depth of fusion
- fusion depth
Related terms
Incomplete penetration
A root left unfused because the weld never reached all the way through a joint meant to be fully penetrated.
Burn-in
Shop word for how deeply a bead melts into the base metal or sidewalls, especially at the root and toes.
CJP
Complete joint penetration: a groove weld that fuses through the full thickness of the joint.
DCEP
Direct current electrode positive: welding polarity with the electrode on the positive terminal.