Local collapse of the weld pool that melts completely through the root or a thin wall, leaving a hole or a sagging drop on the back side. It comes from too much current, too wide a root opening, a knife-edge land or lingering in one spot. Burn-throughs are repaired by grinding back to sound metal and rewelding, and they are a common way to fail a root bend or radiograph.
Burn-through at four o'clock, grind it back to clean metal and bridge it with a couple of quick dabs.
Also heard as
- burnthrough
- blow-through
- blowout
Related terms
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.
Icicles
Slang for drips of excess root metal hanging inside a pipe from too much heat or too wide a gap.
Root pass
The first weld pass in a joint, laid at the root, which sets the quality of everything above it.