Pair of elongated slag inclusions running along both edges of the root bead, which on film look like the ruts left by a wagon. They form when slag collects in the grooves at the edges of a convex stick root and the hot pass fails to burn it out. Grinding the root flatter and running a hot enough hot pass prevent them.
Film shows wagon tracks the whole length, grind that root flatter and hit the hot pass harder.
Also heard as
- wagon track
- railroad tracks
- slag lines
Related terms
Slag inclusion
Nonmetallic slag trapped inside a weld instead of floating out to the surface.
Hot pass
The second pass on a pipe weld, run hot and fast right after the root to burn out trapped slag.
Root pass
The first weld pass in a joint, laid at the root, which sets the quality of everything above it.
RT
Radiographic testing: imaging a weld's interior with X-rays or gamma rays on film or a digital detector.