The effects of flux composition on transfer of the elements have been studied through developed agglomerated fluxes on mild steel plates. The elements transferred to the welds have been shown in terms of a delta (D) quantity, which may be positive, negative or zero depending upon the composition of flux, wire and base plate. Carbon and manganese contents both show negative D quantity for most of the welds, indicating that both have been transferred from the weld metal to the slag. The results of this study show that for most of the welds, desulphurization and removal of phosphorus have been reported. The amount of element transferred is different for different welds depending upon the flux composition, dilution and slag metal reactions. Response surface methodology has been used for developing models for element transfer. The suggested model has been given for sulphur transfer to the weld. In this study the transfers of carbon, manganese, sulphur, phosphorus, silicon and nickel have been studied.Keywords. Submerged arc welding; basicity index; element transfer; slag metal reactions; oxidizing power of the flux. Sådhanå (2018) 43:26 Ó Indian Academy of Sciences https://doi.org/10.1007/s12046-018-0782-5S adhana(0123456789().,-volV)FT3 ](0123456789().,-volV)

Performance of a welding flux is decided by the physical and chemical properties of its constituents.The flux selected should show a good welding behavior and the required weld bead geometry. The mechanical properties of a joint are not only decided by its composition but these also depends on bead geometry, dimensions and physico-chemical properties of fluxes. These properties include surface tension, viscosity, heat capacity, thermal coefficients of expansion, grain size etc. These properties of fluxes primarily affect the flux behavior, bead shape and size, welding speed, current carrying capacity, protection of molten metal, arc stability, slag detachability, capillarity, surface tension and viscosity. Various constituents of a welding flux have major influence on the performance of welding processes and weld bead dimensions. We need to understand the physical properties and behavior of fluxes during submerged arc welding. The influence of specific flux additions on arc stability, viscosity, capillarity, slag detachability and weld bead shape need to be better characterized. It can be inferred that we cannot obtain the weld of desired geometry and composition until we consider the physico-chemical characteristics of flux like slag viscosity, surface tension, arc stability and slag detachability, capillarity and weld penetration. So, while designing the flux or during selection of welding process parameters the above characteristics should be carefully controlled or selected.

No abstract

No abstract

This experimental study reveals the effects of CaF 2 , FeMn and NiO additions to the base fluxes on tensile strength and percentage elongation of the weld metal. The aim of this study is to develop suitable flux for mild steel for high tensile strength, impact strength and ductility. Bead on plate welds were made using submerged arc welding process. Mathematical model for percentage elongation and UTS of mild steel welds were made. The elements transfer to the welds have been correlated with the above mechanical performance characteristics. The effect of oxygen content on weld elongation and UTS also has been deduced. This study shows that CaF 2 and NiO are the significant factors for tensile strength while FeMn is not significant for tensile strength. However, for elongation besides CaF 2 , the interaction of CaF 2 and FeMn was also found significant. The effects of basicity index of the flux and carbon equivalent of the welds on tensile strength and percentage elongation of the welds have also been evaluated.