Arc strikes
Represent any localised heat affected zone caused by an arc. Arc strike tends to produce hardening particularly in high carbon steels and alloy steels. Grinding of cross section of such arc strike points show without exception, the occurrence of untempered martensite with a very high hardness and often cracks are present. At sudden st resses, at low temperature, these places can easily serve as initiation point for brittle fracture. By giving proper instructions to a welder and by good house keeping this can be avoided. By dressing up the area, the ill effects are removed.