The measurement of oxygen pressure of molten submerged arc welding fluxes using disposable oxygen probes

The oxygen pressure of Submerged Arc Welding (SAW) fluxes is a direct measurement of the potential of the flux to give up oxygen to the weld metal. A low oxygen pressure flux is required for producing low oxygen content welds. A needle type oxygen probe was developed for the rapid determination of oxygen pressure in molten SAW fluxes. Yttria doped zirconia was used as a solid electrolyte which conducts only oxygen anions. The molybdenum wire was oxidized to provide the reference oxygen pressure by the Mo/MoO{dollar}sb2{dollar} equilibrium reaction.; It was determined from the results of the oxygen probe measurements that the oxygen pressure (pO{dollar}sb2{dollar}) increased with temperature and the In pO{dollar}sb2{dollar} varied linearly with the inverse of the temperature.; The pO{dollar}sb2{dollar} correlated with the optical basicity of the fluxes at steelmaking temperatures (1600{dollar}spcirc{dollar}C). There was no correlation with the Basicity Index recommended by the International Institute of Welding.; A statistical relationship between the In pO{dollar}sb2{dollar} and the chemistry of the flux was determined, as well as the effects of temperature. An excellent correlation was found between the In pO{dollar}sb2{dollar} and the molar percentages of CaF{dollar}sb2{dollar}, CaO, MnO and SiO{dollar}sb2{dollar} of the flux. (Abstract shortened by UMI.)...