Chemical and structural characterization of the crystalline phases in agglomerated fluxes for submerged-arc welding

A study of chemical and structural characterization of fluxes for submerged-arc welding was conducted. Three flux formulations were prepared using mineral oxides for agglomerating and sintering processes. A commercial agglomerated and sintered flux was used for comparison. The four fluxes were analyzed chemically by atomic absorption and X-ray diffraction to determinate the quantity and type of oxides formed, as well as the change in oxidation number after the sintering process at 950 °C of the initial compounds. Differential thermal analysis was carried out from 1000 to 1350 °C in order to determine the temperatures for phase transformations and melting of the different compounds formed in the sintering process. This kind of flux characterization enables us to quantify the ions that might be present in the plasma arc during the submerged welding process due to the fluxes. This analysis also make possible the prediction of reactions in the weld pool.