APPLICATION OF BARIUM-STRONTIUM CARBONATITE FOR PRODUCTION OF WELDING FLUXES BASED ON SILICOMANGANAZE PRODUCTION SLAG

Abstract

The study results of introduction of barium-strontium carbonatite of various fractional composition into flux based on silicomanganese production slag are presented. The principal possibility of using their mixtures for depositing and welding of low-alloy steels is shown, while the use of barium-strontium carbonatite makes it possible to reduce contamination of weld metal with nonmetallic inclusions. In series of experiments in laboratory conditions, various compositions of welding fluxes were made and investigated. As components, barium-strontium modifier BSC produced by “NPK Metallotechnoprom” LC under TU 1717-001-75073896-2005 was used, wt. %: 13.0 – 19.0 % BaO; 3,5 – 7,5 % SrO; 17.5 – 25.5 % CaO; 19.8 – 29.8 % SiO2 ; 0.7 – 1.1 % MgO; 2.5 – 3.5 % K2O; 1.0 – 2.0 % Na2O; 1.5 – 6.5 % Fe2O3 ; 0 to 0.4 % MnO; 1.9 – 3.9 % of Al2O3 ; 0.7 – 1.1 % TiO2 ; 16.0 – 20.0 % CO2 as well as silicomanganese slag produced by JSC “EVRAZ – West-Siberian Metallurgical Combine”, wt. %: 6.91 – 9.62 % Al2O3 ; 22.85 – 31.70 % CaO; 46.46 – 48.16 % SiO2 ; 0.27 – 0.81 % FeO; 6.48 – 7.92 % MgO; 8.01 – 8.43 % MnO; 0.28 – 0.76 % F; 0.26 – 0.36 % Na2O; up to 0,62 % K2O; 0.15 – 0.17 % S; 0.01 % P. Basis of the flux is silicomanganese production slag, into which a flux additive was introduced. Flux additive was produced in two ways. The first one: by mixing barium-strontium modifier with liquid glass in a ratio of 75 and 35 %, respectively. The second variant is as follows: dust of strontium-barium modifier of fraction less than 0.2 mm was used as a flux additive. The technology of flux-additive manufacturing is described. Welding of rollers was carried out using ASAW-1250 welding tractor. Regimes of surfacing were worked out. The chemical compositions of fluxes, slag crusts, flux and weld metal were determined. Metallographic studies of metal were performed. The results of analysis for presence of nonmetallic inclusions in weld zone were carried out in accordance with GOST 1778 – 70. Studies indicate a decrease in contamination of weld metal by silicates that are not deformed and absence of brittle silicates.