Vol 2017, No 12 (2017)

The influence of argon blowing of the EP602 alloy melt in a ladle is considered. Ladle treatment during the manufacture of nickel superalloys is shown to form a more equilibrium and homogeneous structure of a melt, which leads to changes in the structure and properties of the solid metal.

The interaction of the nickel melt containing REMs (Y, Ce, and La) with the ceramic material of a melting crucible (Al₂O₃, MgO ∙ Al₂O₃, Y₂O₃) during vacuum melting and with a mold (Al₂O₃) during directional solidification of has been detected experimentally. The REM concentration in a metal decreases as a result of holding of an REM-containing melt in a ceramic crucible or a mold. This should be taken into account to achieve the optimal required REM content in alloys.

The behavior of carbon–graphite subjected to treatment in the lithium carbonate Li₂CO₃ melt without cryolite and alkali-metal fluorides is studied to reliably estimate the influence of lithium on the surface layers of a carbon-containing cathode lining. The chemical composition and the structure of the carbon–graphite material after its interaction with lithium in the Li₂CO₃ melt have been studied. The high-temperature interaction of the system components in the melt is found to be accompanied by fracture of the operating surface of the carbon–graphite material, while the carbon–graphite surface does not failed upon interacting with lithium vapors. Based on the obtained data, a model for the formation of lithium ions during the reduction of lithium and its interaction with a carbon–graphite sample during the electrolysis of lithium carbonate is proposed.

The problems of the production of a so-called casting rod blank made of a refractory casting alloy in the vacuum induction furnaces of AO Metallurgical Plant Electrostal are considered. A unique technology of casting and subsequent treatment of as-cast rod blanks made of refractory alloys is developed, tested, and optimized. As a result of the developed and performed measures for the production of metal products in the Consarc furnace, the ingot-to-product yield increases by 15% as compared to metal casting in an ISV-1.0 furnace. As a result, we have widened the range of cast alloy grades and are going to cast metals for the manufacture of blanks of other sizes and ranges of alloy an steel grades.

The effect of the initial grain size in the structure of the aluminum 1565chM alloy on the mechanical properties of the welded joints formed by friction stir welding and on the grain size in the weld core is studied. It is shown that the design of tool and, especially, the parameters of a screw groove exert a great effect on the grain size in the weld core.

The changes in the phase compositions of various protective coatings that occur during heat resistance tests are studied. The intensity of exhaustion of their protective properties as a function of the chemical and phase compositions of a coating is investigated. It is shown that the life of a coating can be increased due to the retardation of the diffusion processes occurring between the coating and the base alloy.

A powder metallurgy method is developed to recondition the worn surfaces of food and processing equipment components. A combined additive is composed to minimize the powder losses in sintering. A technique is constructed to determine the powder consumption as a function of the required metallic coating thickness. A rapid method is developed to determine the porosity of the coating. The proposed technology is used to fabricate a wear-resistant defectless metallic coating with favorable residual stresses, and the adhesive strength of this coating is equal to the strength of the base metal.

The microstructure, the segregation of alloying elements, and the diffusion processes in the ZhS32-VI nickel superalloys fabricated by single-crystal casting and argon gas atomization followed by vacuum heat treatment are studied by scanning electron microscopy and energy dispersive electron-probe microanalysis. It is found that vacuum heat treatment at 1280°C of ZhS32-VI alloy granules without the application of external pressure can be used to fabricate a homogeneous alloy with a polycrystalline structure and a grain size of 10–30 μm. The microporosity in this alloy is no higher than that in cast nickel superalloys.

The results of producing metal products of the steel and alloy ingots manufactured on an ALD furnace are presented. Remelting with growth rate and drop pulse frequency control is tested. (08‒12)Kh18N10T steel is studied to determine the depth of shrinkage and subshrinkage defects in all ingots of all sizes (250, 320, and 500 mm in diameter). The quality of steels and alloys in chemical composition, mechanical properties, long-term strength, macrostructure, and nonmetallic inclusions are analyzed in terms of regulatory documents. The affordability of the implemented remelting process was about 4.4 mln rubles.

The powder fabricated by electric discharge dispersion of the wastes of a VK8 hard alloy is studied by electron-probe microanalysis. This powder formed by electric discharge dispersion in kerosene mainly contains tungsten and carbon and has low contents of oxygen, cobalt, and iron.