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The peculiarities of the process of forming complex compounds, namely, spinels, in flux-cored arc welding for the slag TiO2-MnO-SiO2-MgO-CaO-FeO-Al2O3 system are studied. An experimental investigation of the mechanism of spinel formation in conditions of electrode arc welding and cladding under flux is carried out. Based on the analysis of microimages of the slag surface obtained using scanning electron microscopy, the mechanism of spinel formation, namely, the growth of microcomplex compounds into macrospinels, is presented. The main stages and mechanism of formation of the complex compounds, namely, spinels, are described. As shown, the structure of spinels is determined by the temperature conditions of the crystallization of the slag melt. The study reveals that one of the determining factors of high-temperature separation of the slag crust during multilayer cladding with overlap of the previous layer is the formation of spinels at the interphase boundary between the slag and the metal. Based on modern ideas about the structure of slag melts, a mechanism for the formation of complex compounds at the interphase boundary between slag and metal is proposed. The main factor determining the process of high-temperature separation of the slag coating for the TiO2-MnO-SiO2-MgO-CaO-FeO-Al2O3 system is the formation of complex compounds based on spinel-forming elements and slag oxides at the interphase boundary between the slag and the metal. [ABSTRACT FROM AUTHOR]

The composition of the ladle slag in units designed for the secondary treatment of steel needs to be optimized in order to increase the service life of the units' linings. On the one hand, the slag subjects the refractories to chemical wear. On the other hand, under certain conditions the slag is capable of forming a protective crust inside the units. The Nizhniy Tagil Metallurgical Combine has chosen certain refractories for the most heavily worn part of the lining of its vacuum chambers, since only the installation of a lining of a differentiated design that equalizes the rate of wear around the lining's perimeter will allow the desired effect to be obtained from optimizing the composition of the slag. An efficient composition for the slag was also chosen, the slag having high contents of MgO and AlO. The use of such a slag helps form a protective slag crust of the composition MgO·AlO on spinel refractories having the compositions MgO·CrO and MgO·AlO. [ABSTRACT FROM AUTHOR]