For the shielded metal arc welding process, attention was directed toward the selection of the class of covered electrodes based on their usability factors. All the electrodes described in AWS specification A5.1 are applicable to the mild and low-alloy steels. The E-60XX and E-70XX classes of electrodes provide sufficient strength to produce 100% weld joints in the steels. The yield strength of electrodes, in these classes, will overmatch the yield strength of the mild and low alloy steels. The E-60XX class should be used for steels having yield strength below 350 MPa and the E-70XX class should be used for welding steels having yield strength below 420 MPa. Low-hydrogen electrodes should be used and preheat is suggested when welding heavier materials, or restrained joints. The electrode that provides the desired operational features should be selected.

Strength si riferisce alle caratteristiche di resistenza (a fatica) della saldatura, in questo caso indica che la saldatura deve avere come minimo le stesse caratteristiche di resistenza del metallo che viene saldato (100% strength or full strength)