Results related to improvements in the technology of articles made of fibrous composite materials for induction plants employed to heat metallic billets through the use of highly concentrated binder suspensions in the composition of the articles are presented. By comparison with the AKBF articles that are usually used for these purposes, the new articles possess improved operating characteristics.

Service conditions for refractories and physicochemical processes at their contact with molten aluminum are provided. Thermodynamic calculations establish the relative wear resistance of a number of oxides, silicates, and oxygen-free compounds towards aluminum in the range 700–1200°C (937–1473 K). The role is revealed of contact physicochemical processes at the boundary of a refractory with molten aluminum. The high resistance towards aluminum is demonstrated for high-alumina calcium aluminates, particularly bonite CaO · 6Al2O3 and spinel MgO · Al2O3. The most practicable wear-resistant fuzed materials for preparing lining of melting furnaces are lime-aluminate slags of OAO Klyuchevsk Ferroalloy Plant.

The service results of submerged-resistor induction furnaces for pig iron exposure of the vertical (capacity 30 tons) and horizontal (capacity 60 tons) types at the AMO ZIL Works are described. The furnace lining is made of KSVKh-1 corundum mixture by casting. The lining is found to be reliable in service, and its resistance is more than two times higher than that of mixture MK-90.

Development results for refractory mixes based on fused corundum, spinel, and quartz glass and intended for use in the ferrous and nonferrous metallurgy (induction and channel-type furnaces, mixers for iron and aluminum casting technologies) are reported. Unlike the conventional mixes, the newly designed mixes can be used to prepare dry mixtures and cement-free castables. Results of industrial tests are given.

Results for corundum-based fibrous composites used as refractory materials in the fabrication of aluminum and Al-based alloys are reported.

The development and industrial applications of new corundum and bauxite-based mixtures for the refractory lining of iron-melting units (furnace, crucible, ladle), and a new mortar for refractory brickwork, are reported.

The KSVKh-1 refractory mixture (available from the REIN JSC) was tested as a material for the lining of an LFR 30/CSH channel-type induction mixer under industrial conditions at the AMO ZIL automobile plant. The mixture was used to prepare the lining for the bath and nozzles by a castable technology; it showed a high resistance to wear and good service characteristics for a period of one year at least.

The proposed method and program for calculating the compressible turbulent boundary layer in rocket engine nozzles with gas film cooling make it possible to determine the specific impulse losses due to friction, the heat fluxes and other characteristics of the flow. The calculations are based on the numerical solution of the equations of gas dynamics in the boundary layer approximation using a three-parameter differential turbulence model.

has been used and improved since the start of the 80's. At present the parameters of the steel-tapping assembly, the configuration of the refractories, and their properties have been stabilized [2]. Parts for submerged tapping are mass produced to TU 14-8-463-90 from fixed periclase and graphite with a bakelite binder, pressed at high pressures,and heat treated at 180-200~ As a result the life of elements of the submergedtapping unit was 40-120 heats in 1991 (Table I). As follows from the results of observations of the service of the refractories in a steel submerged-tapping assembly (Table 1), the linings of the lower and upper portions of the channel, that is, the sleeve and the upper tube, are subjected to the most wear. In connection with this the sleeve may be replaced once or twice during a campaign of the channel or repaired. The character of failure and rate of wear of the parts depend upon their location in the lining of the steel-tapping assembly and the service conditions. Photographs of a sleeve used for 54 heats in a 100-ton arc furnace and of the upper edge of the steel-tapping channel on the side of the working space of the furnace after 47 heats (Fig. 1) confirm the intense wear of the elements of the lining of the submerged-tapping channel in its lower and upper portions. The used parts have a zonal structure with different sizes and degrees of expression of the working zones. Normally the working zone of the tubes and the sleeve is a 2-3 mm thick slagged crust. After it follows a I-3 mm thick zone of increased looseness, after which is observed the least-changed portion of the lining. The crust is impregnated with the components of the slag and iron oxides. For example, the working zone of the used periclase-carbon tubes contains (wt.%) 11.6 MgO, 37.8 CaO, 8.5 SiO2, 1.5 A1203, 35.3 Fe203, 1.8 Cr203, and 0.29 C (Amcale). The loosened zone does not contain reactants introduced from the working space of the furnace but differs from the unchanged portion in a reduced carbon content. Partial burning off of the carbon in the loosened zone as the result of oxygen contained in the atmosphere and the molten steel weakens the bond in the structure of the part and makes the zone weak and easily eroded by the moving metal. This is promoted by the high rate of movement of the metal (3-4 m/see), the rotary movement of the stream, and the high temperatures.