Relationship between quality, manufacturing technology and structure of welding fluxes

Technology for manufacturing of fused fluxes of the AN-67 grade (preparation of charge, melting of flux in electric arc furnace, granulation (pouring of melt into water), drying, screening and packing) was developed in such a way that the resulting granulated welding flux had a fully amorphous structure. However, production of such fluxes involves enormous power expenditures. Therefore, the trend with flux manufacturers is to reduction in time and decrease in ultimate temperatures of the processes, which makes it impossible to remelt high-temperature components of the flux charge. Some welding fluxes of the AN-67 series were examined by the X-ray diffraction method. It is established that certain fluxes produced in the last years contain crystalline components with a high melting point, such as Al2O3 and CaF2, in addition to the amorphous phase. The paper shows the negative effect by this factor on properties of the fluxes