Modifiing Effect of Zirconia Nanoparticles during Electric Arc Welding

The structure of the weld metal after welding using a flux-cored wire with the addition of 0.3% zirconia flaky nanoparticles is studied. The weld consists of an acicular ferrite. This finding can indicate that the dissociation of zirconia in an electric arc is not an obstacle to a modifying effect, which manifests itself in both the interaction of zirconium with oxygen and the surface activity of zirconium in an iron-based solidifying melt. Thus, zirconia is a modifier of both the first and second kinds for the solidifying weld metal. Excess oxygen is likely to form individual pores less than 1 μm in diameter in the weld metal; however, they only wealy affect the mechanical properties of the welded joint. These results will be used to develop electrode materials for welding pipe steels.