Use of barium-strontium modifier for the manufacturing of welding flux based on silicomanganese slag

The possibility of using a barium-strontium modifier as a gasprotective and refining additive for welding the fluxes based on crushed slag from the production of ferrosilicomanganese is presented. The barium-strontium modifier BSK-2 produced by JSC “NPK Metalltekhnoprom” according to TU 1717-001-75073896–2005 was used as a material for the study. The base of the welding flux was silicomanganese slag produced by the West Siberian Electrometallurgical Plant. The research work on new welding fluxes and flux-additives was carried out using the equipment of the Scientific and Production Center “Welding Processes and Technologies” and the Center for Collective Use “Materials Science”. The use of barium-strontium flux additive was carried out in two ways. In the first option, the flux-additive was made by grinding barium-strontium to a dust-like fraction of less than 0.2 mm with further mixing with liquid sodium glass, drying in a furnace, crushing and separating a fraction of 0.45 – 3.00 mm. In the second option, the flux additive was used in the form of dust with a fraction of less than 0.2 mm. The additives were mixed at a ratio of 2 – 10 % of mass of the slag produced by silicomanganese. Surfacing of the samples was carried out with a welding wire of the sv-08GA grade on a substrate of steel grade 09G2S with a thickness of 20 mm. Quality of the deposited metal was studied, the chemical compositions (deposited layers, slag crusts, the used flux) were investigated by X-ray fluorescence method on XRF-1800 spectrometer and by atomic emission method on DFS-71 spectrometer. The degree of contamination with non-metallic inclusions (non-deforming silicates, point oxides, sulfides) was studied using OLYMPUS GX-51 optical microscope in the magnification range from 100 to 1000. The laboratory studies on the surfacing of steel samples have shown that due to introduction of a flux additive made from barium-strontium modifier, the metal is refined, and the concentration of sulfur and phosphorus decreases. The use of a mixture of a barium-strontium modifier with liquid glass as an additive is preferable to the use of an additive in the form of a dust. It was revealed that the best samples from the point of view of the degree of contamination of the deposited metal with nonmetallic inclusions are samples made using no more than 8 % of barium-strontium flux additive.