New capabilities of the oldest enterprise on production of welding fluxes

Abstract

At Company «Zaporozhstekloflyus» the technology of two-stage melting of flux (duplex-process) was mastered, where firstly the charge is melted in separate melting unit, and then the melt is finally melted in another unit. This allowed decreasing the content of harmful impurities in melt: oxides of iron and sulphur by 2-3 times, phosphorus -by 4-6 times, and, thus, improving the flux quality. In addition, raw base for production of fused fluxes was widened that is extremely important under conditions of deterioration of raw material quality. Due to the double refining of melt of fluxes the duplex-process solved in principle the problem of utilization of slag crust, formed in submerged-arc welding. Production of fused semi-products designed for application in charge of welding consumables (covered electrodes, flux-cored wires and agglomerated fluxes) was mastered. Submerged-arc welding is the leading technological process in manufacture of large-size welded metal structures. Among four components of this process, such as welding equipment, base metal, welding wire and flux, a high quality of the latter and its welding-technological capabilities provide a user with required technical and economical characteristics of welding, and remain a decisive factor for a manufacturer of fluxes in sale of the own products.However, the traditional technologies of manufacture of welding fused fluxes, i.e. melting in open gas or electric arc furnaces can already scarcely deal with this problem. The reasons are not only in deterioration of quality of traditional raw materials and growth of requirements to the quality of welded metal structures, but also in the technologies themselves, as each transition in flux melting from one grade to another or change in quality of charge consumables determine the efficiency of flux melting furnaces, influences the life of lining, predetermine the volume of consumption of power carriers, and result, as a rule, in additional production costs.In the last years the requirements to restriction of content of harmful impurities in steels of critical welded structures were rapidly increased [1,2]. To provide the required characteristics of quality of welded joints, it is necessary to restrict the content of these impurities in fluxes. Thermodynamic analysis of pyrometallurgical processes, running in flux melting furnaces, showed complications of simultaneous decrease in sulphur and phosphorus in the melt [3].Appearance of two-stage flux melting (duplex-process) [4], at which the charge is melted at the separate melting unit and then at the second one its refining is performed, allows not only decreasing the content of oxides of iron, sulphur and phosphorus in the melt and thus improving the quality of flux, but also extending the source of raw materials for production of fused fluxes, which is extremely important under the conditions of deterioration of quality of raw materials. Besides, due to double refining of melt of fluxes the duplex process almost solved the problem of utilization of slag crust...