On possibility of using silicomanganese slag and ladle electric steelmaking slag in manufacture of welding fluxes

Analysis of the existing trends in development of technologies for production of welding and surfacing fluxes showed that one of the actively developing areas is the production of fluxes using man-made waste (including metallurgical one) as components of the initial charge. This is due to the fact that the slag waste of metallurgical production contains a large amount of manganese and silicon, which in turn are the basis in welding fluxes. Within the framework of this direction development, the article describes principal possibility and efficiency of using materials based on ladle electric steelmaking slag from JSC “EVRAZ United West Siberian Metallurgical Combine” and slag produced by silicomanganese from LLC “West Siberian Electrometallurgical Plant” in the charge for production of fluxes used in the surfacing of rolling rolls. All the laboratory tests were made using the equipment of the scientific and production center “Welding Processes and Technologies”. For surfacing steel samples, the authors used a flux additive obtained by mixing ladle electric steelmaking slag of a fraction less than 0.2 mm with liquid sodium glass in a ratio of 62 and 38 %. The resulting flux additive was mixed with slag from the production of silicomanganese of a fraction of 0.45 - 2.50 mm in various ratios. Studies of the chemical composition (by the spectral method) and metallographic studies of the deposited layer revealed a tendency to an increase in sulfur content and in contamination with non-metallic inclusions in it with an increase in content of the flux additive in the charge of more than 20 %. According to the results of visual quality control of the deposited layer macrostructure, the absence of defects was established with a flux additive content of up to 30 %.

The Experimental Study of Innovative Methods Regarding the Removal of Sm(III)

The modern development of the construction materials sector determines the use of rare earth metals (REM) for various purposes. In particular, REM are added as basic alloying elements into magnesium alloys to increase alloy durability and strength. The complex systematic study of structural components and REM interaction are the basis for the phase state monitoring of multicomponent oxide polyfunctional materials. In addition, on the preparatory stage, layers with specified construction material coatings are formed. The paper presents experimental and theoretical results of studies of adsorptive bubble methods in the systems containing Samarium cations and surfactants, namely sodium dodecyl sulphate (NaDS). To identify the process mechanisms and prediction of optimal conditions of metal cations’ removal and separation by extraction, flotation, and ion flotation methods, one should know the pH of metal hydroxo-complexes and pH of the hydrate formation. The possibility of lanthanide ions’ removal (by the example of Samarium ions) by the solvent sublation method with NaDS as a collector and isooctyl alcohol as an extractant was studied. From the obtained experimental data, it was clear that the Sm3+ removal in acidic mediums is practically non-existent. The results obtained in this paper are topical in the production of electrode coating components, welding fluxes, sorbents for nuclear wastewater burial, wastewater treatment, highly porous heat-insulating and fire-resistant materials, cement, and concrete with improved frost resistance.

Effect of SAW fluxes on electrochemical corrosion & microstructural behavior of API X70 weldments

High-performance pipeline steels are frequently used for storage, transportation and energy development applications. Submerged arc welding finds its application to weld thick pipes. Design and development of appropriate welding fluxes provide good structural integrity properties in severe service environments. The present study aims to investigate the effect of laboratory-developed SAW fluxes on the electrochemical corrosion behavior of SAW weldments in different environments. Electrochemical corrosion behavior of weld specimens in different environments was performed using Linear Sweep Voltammetry. Different mediums such as seawater and sodium thiosulphate solution (10−2 Mol/l, pH = 3, and 10−3 Mol/l, pH = 5) were taken for the corrosion study. The microstructure of the weld specimen reveals the presence of acicular ferrite structure. F3RA and F19RA weld specimen shows a higher corrosion rate in seawater and sodium thiosulphate medium (pH = 3 or 5).

Experimental investigation of structural integrity behavior of High strength low alloy steel – Study of mechanical, microstructural and corrosion behavior of Submerged arc welding weldments

The present study aims at investigating the effect of submerged arc welding fluxes for enhanced corrosion resistance of structural steel welds. By varying the basicity index of submerged arc welding fluxes the corrosion resistance and mechanical properties of weld metal such as tensile strength, impact strength, microhardness in submerged arc weldments were evaluated. The result shows that with the increase in bascity index tensile strength of weld specimen reduced while impact strength and microhardness value increased. Maximum microhardness (288 HV) was observed for flux 2 while base metal show minimum microhardness value (205 HV). Flux 5 gives maximum impact strength (94.17 J) as compared to the base metal (80 J). This is due to the reduced content of oxygen in weld metal which increases the weld metal impact toughness. Corrosion resistance of weld specimen increased as compared to the base metal. Ductile fracture mode and shear lip or tears were observed in the weld zone. Shear dimples and shear lips were more severe in base metal as well as weld metal impact specimens due to the rapid effect of external forces on the impact test. The banded microstructure of delta ferrite and austenite was observed in the base metal. Fine grains of ferrite and pearlite at the center and edges were present in the weld zone.

Effect of additives introduction to fluxes manufactured from ladle electric steel slag

Studies of welding and surfacing fluxes containing ladle slag of electric-steel production of rail steel of JSC “EVRAZ ZSMK” were carried out. Welding under the flux was performed on the samples of sheet steel 09G2S by Sv-08GА wire using the weldingtractor ASAW1250 at exhaust modes. Chemical compositions of welding fluxes and slag crusts were determined. Also chemical composition of the studied welded samples was determined according to GOST 10543 – 98 by x-ray fluorescence method on XRF-1800 spectrometer and by atomic emission method on DFS-71 spectrometer. Metallographic studies were carried out with the use of an optical microscope OLYMPUS GX-51. The content of total oxygen and surface oxygen was studied using the LECO TC–600 analyzer. The possibility of using technogenic waste products of metallurgical production is shown for the production of welding fluxes. The following components were used for production of welding flux: ladle slag of electric steelmaking of rail steel from “EVRAZ ZSMK” JSC; BSK barium-strontium modifier produced under the terms of 1717-001-75073896 – 2005 by “NPK Metallotekhnoprom”; slag of silicomanganese production from “West Siberian steel plant”; electrostatic dust of aluminum production from “RUSAL” (carbonfluor-containing supplement). The studies have shown the suitability of the use of ladle electric steel slag for welding and surfacing of alloyed metal. The introduction of various flux additives reduces the concentration of total oxygen in the weld metal, which in turn increases the toughness. From the point of oxygen concentration in weld metal and impact toughness, it is better to use silica-manganese slag and carbon-fluoride additive as flux additives.