When using
DC arc welding, straight
polarity refers to the
electrode being the
positive terminal (
cathode) and the
workpiece being
negative (
anode). Thus,
electrons bombard the electrode from the workpiece. Straight polarity generates shallow
penetration into the workpiece and a wider
bead of
weld. In
AC welding, the reverse polarity portion of the
cycle is responsible for the cleaning action around the weld, especially useful with
aluminum and
magnesium.