44 Arc Strikes

Arc strikes are depressions or marks that occur on the surface of the weld by the welder accidentally striking the electrode on the base metal face away from the weld joint. This causes the area struck to melt and rapidly cool due to the massive heat sink of the surrounding base metal.

On certain materials, especially high strength steels, this can produce a localized heat affected zone that may contain martensite which increases the potential for cracking. Numerous failure of structures and pressure vessels can be traced back to the presence of a welding arc strike. Arc strikes are thus unacceptable.

Arc strike detection is achieved by visual examination (VT). Some fabrication standards and codes require arc strikes to be ground to a smooth contour and inspected to ensure soundness by an appropriate nondestructive examination method such as VT.

Arc Strike Prevention

Arc strikes are prevented on certain types of work, such as pipe, by placing protective wrappings around the part to prevent accidental contact with the electrode.