The influence of electrochemical reactions induced by an external circuit on submerged arc weld metal

Based on electrical conductivity of molten slag, a new method of applying direct current external circuit between slag and pool to control inclusions and improve weld bead appearance was designed and tested. The results show that the effect of the external circuit can effectively reduce the size of inclusions in weld metal. As the cathode of the electric field, a W-(2 wt%)Ce electrode inserted into molten slag induces electrochemical reactions and results in the reduction of sulfide inclusions in weld metal. Moreover electron emission of W-Ce electrode improves arc characteristic and makes an improved weld bead appearance.