Small scar of remelted or heat-affected metal left wherever an arc touches the base metal outside the joint, from a careless strike, a live electrode brushed against the work or a loose ground. Arc strikes cool very fast and can form hard, brittle martensite and tiny cracks, so pressure, pipeline and fatigue-loaded work requires them to be ground out and checked with MT or PT. Strikes belong inside the joint or on a run-on tab.
Arc strike outside the bevel, grind it smooth and get MT on it before the coating crew shows up.
Also heard as
- stray arc
- arc burn
- strike
Related terms
MT
Magnetic particle testing: finding surface and near-surface cracks in steel with a magnetic field and iron powder.
HAZ
Heat-affected zone: base metal next to a weld whose structure changed from the heat but did not melt.
Ground
Shop word for the work lead and its clamp, which completes the welding circuit through the part.
VT
Visual testing: inspecting welds by eye with gauges, lights and magnifiers, the first and most-used NDE method.