Russian Metallurgy (Metally)最新文献

Polarization measurements of organic surfactant systems on the steel surface in the Tafel coordinates are performed. The corrosion parameters are calculated. An inhibition effect of the systems under study on the supporting solution is revealed. Synergism has been revealed.

The mechanical properties of deformed semifinished products made of titanium alloys manufactured at different enterprises in the period from the 1970s to the present time are studied. The statistical dependences of the standard mechanical properties on the chemical composition, structure, annealing conditions, and test temperature are revealed from the generalization of the published data and results of industrial tests, industrial control, and own experiments. Recommendations aimed at enhancing the quality of the semifinished products from Ti–6Al–4V alloys are proposed. A prototype has been developed for a “Titanium Alloys” automated information system with the possibility of predicting the properties of titanium alloy semifinished products.

Heat treatment conditions are chosen in accordance with alloys and production method of blanks and parts made from them. The heat treatment of parts produced from aluminum alloys is based on the fact that, as the temperature decreases, the solubility of many elements in solid aluminum deceases. The aim of the present study is to investigate the effect of heat treatment conditions of a wrought aluminum alloy on its structure and properties and, based on the data, to choose more rational technological heat treatment conditions.

A technology of producing a high-quality hafnium–nickel GfNi10 master alloy is developed: it is produced in a vacuum arc furnace with a nonconsumable electrode using a preliminary annealed pressed electrolytic hafnium powder. The total content of impurities and oxygen and nitrogen gases in the master alloy is found to be substantially lower than that in a serial GFN-10 master alloy. The character of interaction of the master alloy with the nickel melt during vacuum induction melting of the new VZhM200 cast nickel superalloy shows that, in contrast to a GFN-10 master alloy, the GfNi10 master alloy produced in VIAM gives no melt splashes during the introduction of the master alloy; this increases the assimilation of hafnium. The chemical composition and mechanical properties of a serial VKNA-1VR alloy and the new VZhL125 nickel superalloy melted with the developed master alloy correspond to the requirements of specifications for these alloys. In addition, high hafnium assimilation and low contents of gas impurities are ensured.

Abstract—This paper presents experimental results on the machining of parts fabricated from powder materials. The specifics of porous surface structure formation in powder-metallurgy parts upon abrasive finishing are described.

The results of experimental studies of the composition, structure, and properties of a lead–antimony alloy sintered from an electroerosive powder formed in distilled water are presented. Spark plasma sintering used to synthesize products from the powder produced by electrodispersion of an SSu-3 alloy is shown to manufacture alloys for the production of current lead plates for acid batteries due to the confirmed anticorrosive properties improved compared to the initial alloys.

Abstract—The effect of the initial current distribution on the nonuniformity of the distribution of the material removal rate on the surface of a product processed by plasma electrolytic polishing has been studied. Plasma electrolytic polishing experiments have been carried out to reduce the surface roughness on samples obtained by selective laser melting. The analysis of experimental data has made it possible to hypothesize that the electric charge distribution on the surface of the processed product plays a key role in a change in linear dimensions. After the performed analysis, it has been theoretically justified that the initial current distribution is important. On the basis of the data obtained in this work, it has been concluded that a sharp increase in the current density due to edge effects accelerates the metal dissolution process, which can in turn lead to inadmissible changes in the shape and dimensions of the processed product. It is necessary to improve the method and to study the physics of processes of plasma electrolytic polishing in order to integrate it into additive manufacturing as one of the key techniques for postprocessing of pieces.

Abstract—A method for commuter-assisted development of the optimum compositions of new nickel superalloys using the Approx computer method, which has the highest accuracy, is presented.

Abstract—A comparison of two methods of electroslag remelting (ESR) of consumable electrodes is presented, with continuous and cyclic process management and changing consumable electrodes during melting. Technological and technical-economic aspects of choosing the type of ESR are considered. Analysis results and experimental study of the influence of a power input interruption, which occurs when changing an electrode during cyclic ESR, on the quality indicators of a melted ingot are presented. In contrast to cyclic ESR, continuous electroslag remelting of non-replaceable consumable electrodes is shown to ensure the fulfillment of strict requirements for the homogeneity of an ingot structure and the mechanical properties and characteristics of products.

Abstract—The formation of slag binders, which ensure the strength properties of iron ore pellets during reduction, is studied. The formation of dicalcium ferrite, which is not reduced, has been found. The formation of an irreducible binder, namely, dicalcium silicate (belite) is also discovered. However, this compound is characterized by low strength properties and cannot provide high metallurgical properties of the pellets. We decided to continue the search for the binders that provide high strength properties of pellets during reduction.