Russian Metallurgy (Metally)最新文献

The results of the study of platinum(IV) and platinum(II) adsorption and desorption on the anion exchanger macroporous styrene-divinylbenzene matrix Seplite D194 in dynamic mode are presented. It was established that the best platinum adsorption result of 98.37% was obtained at a pH of 0.1 for the platinum-containing solution and a solution-to-ion-exchanger (liquid-to-solid) ratio of 5.

The incorporation into the engineering standards of new high-strength cast iron grades characterized by increased ductility and quite high strength prompted a review of the new class of cast irons. These cast iron grades are distinguished by an increased silicon concentration of 3.2 to 4.3%. The main stages in developing and standardizing this new class of cast iron are outlined. The specified cast iron properties are shown to be achieved through solid solution strengthening of ferrite (SSF) with silicon. Typical problems that arise during the production of this cast iron are analyzed. The requirements for manufacturers introducing a new class of silicon-containing, high-strength cast irons are described. Ways to further improve this cast iron are presented, along with examples of its use in mechanical engineering and energy sectors.

We consider copper metal formation from copper sulfides with allowance for the nature of the Cu–S coordination bond, confirmed by thermodynamic and experimental studies of reactions between elemental sulfur and sodium hydroxide. A special role in reduction processes is played by a parallel reaction yielding polysulfides (sulfur sulfides), which have high reactivity with the copper being reduced.

We have studied the effect of heat treatment (HT) and controlled rolling followed by accelerated cooling (CR + AC) on the structure–phase state of and nonmetallic inclusions in 10KhSND steel. The results demonstrate that the main distinctions between the microstructures of the samples we studied are related to the morphology of the carbide phase. After controlled rolling followed by accelerated cooling, the carbide phase in the steel had the form of lamellar pearlite, whereas quenching and tempering led to the formation of platelike, grain-boundary, and small spherical carbide particles.

The results are presented of diffusion alloying in the medium of low-melting liquid-metal solutions (DALLS) of St3, 40Kh, and 40Kh13 steels in a Pb–Li eutectic medium with the addition of Ni and Cu. Coatings 16–20 μm thick were formed as a result of DALLS. The maximum coating thickness was observed on St3 steel and amounted to 20 μm. On 40Kh steel, the coating thickness was 17 μm, and on 40Kh13 steel it was 16 μm. Structurally, the coatings consisted of surface and transition layers. The content of alloying elements in the coatings also depended on the substrate material. On 40Kh13 steel, the maximum nickel concentration was 46% and the copper concentration was 13%. On 40Kh steel, the maximum nickel concentration was 44% and the copper concentration was 11%. On St3 steel, the maximum nickel concentration was 40% and the copper concentration was 9%. In all cases, the nickel diffusion depth exceeded the copper diffusion depth. The microhardness of the coatings at a depth of 5 μm was 125 HV_0.02 for St3, 130 HV_0.02 for 40Kh, and 140 HV_0.02 for 40Kh13 steel.

The effect of aluminum nitride nanoparticles on the mechanical properties of the granulated heat-resistant nickel-based alloy EP741NP was studied. A correlation was found between the change in mechanical properties of the heat-treated material modified with nanoparticles and the weight content of these particles. The introduction of aluminum nitride nanoparticles indicated the promising potential of using them as a modifier for nickel-based alloys.

A review is presented of the current state of the problem of producing composite materials based on immiscible component systems. A classification of immiscible component systems is given in relation to the production of materials with special properties, such as antifriction, wear-resistant, and damping materials, among others. An in-depth analysis is provided of existing methods for producing materials based on immiscible component systems. The trends in the development of technologies for producing these composite materials are outlined.

Brass and a copper- and zinc-based mechanical mixture of similar composition have been shown to differ in oxidation behavior under identical conditions in reaction mixtures containing iodine and hydrogen peroxide. We have studied the kinetics of consumption of copper and zinc present together in mechanical mixtures differing in the ratio of the metals and demonstrated the feasibility of using weak organic acids for oxidation of brass and mechanical mixtures of metallic copper and zinc.

Seamless hot-deformed pipes with an internally ribbed surface are a promising type of metal products designed for use in modern high-efficiency boiler installations. The presence of a profiled internal surface creates certain difficulties in manufacturing pipes and controlling their quality. Based on an analysis of production of pilot-industrial batches, a procedure is proposed for controlling the geometric parameters of pipes with helical ribbing on the internal surface.

Relationships are proposed for calculating stresses during drawing with heating of a cylindrical workpiece without wall thinning. The material in the deformation region is assumed to be anisotropic and viscoplastic. The Laplace equilibrium equation and the von Mises–Hill yield criterion for the plane stress state of the material are used. The stresses in the deformation region are presented as resolving functions depending on a parameter. The calculated results are given.