The modern trend in the development of engineering is characterized by everincreasing de mands on the quality of the metal products used for this. It is impossible to improve the quality of metal pro ducts without improving technologies for the smelting and casting of metal alloys.Problem Statement. It is known that metal products made from the cast billets with a dispersed crystalline structural structure have a minimum level of licensing and favorable results of nonmetallic inclusions, and have the highest level of mechanical properties. To obtain a cast metal with such a structure, it is necessary to ensure the maximum crystallization rate and the amount of supercooling at the phase boundary, which, when real billets are formed, progressively decrease as the thickness of the hardened metal crust increases (5-10 times).Purpose. Development of scientifically based technological methods for controlling the formation of a cast structure of metal billets by means of thermoforce external influences on liquid and hardened metal.Materials and Methods. An alloy of camphene with tricycylene, which, like metals, crystallizes in the tem perature range (45-42 °C) with the formation of a dendritic structure, and also has the following original prop erties. Aluminum of technical purity A5, which crystallizes with the formation of a very wide transcrystallization zone, was used as a metal system in the work. And it is convenient to evaluate the relative effectiveness of the impact of various methods of external influences on the formation of the crystalline structure of metals by their influence on the width and dispersion of the transcrystallization zone.Results. Experimental studies have confirmed the ability to control the formation of the structure of cast met als using various methods of external thermoforce effects on liquid and hardened melt. Conclusions.The results obtained open up the prospect of developing new metallurgical technologies for the effective management of the cast metal structure at the first stage of production of billets.

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A method of physical modeling was applied to study the effect of external actions on the processes of crystallization and the formation of the structure of ingots. A brief review of existing hypotheses about the evolution of physical, structural, and chemical heterogeneities in large steel ingots is given. The parameters of the structure and the two-phase zone have been determined, as well as the nature of the distribution of segregated materials along the cross-section of ingots, depending on the conditions of their curing. The decisive importance of convective and capillary mass transfer in the interdendritic channels of hardening ingots on the formation of a zonal heterogeneity at their cross-section has been proven. Experimentally, when crystallizing a model environment (camphene), it has been visually confirmed that the flow of segregated materials in interdendritic channels occurs when a certain amount of impurities accumulates in them. A clear dependence of the speed of this flow on the rate of melt crystallization has been established. With an increase of the hardened part of the melt, the rate of segregated material movement (Vl) increases while the rate of crystallization (R) decreases due to worsening heat release conditions. At a certain distance from the ingot’s surface, these rates become equal, and impurities are carried to the curing border, which is the main cause of the formation of zonal segregation. The results reported here show that the evolution of zonal segregation in ingots can be controlled using various techniques involving external influence on the hardening melt. This study has demonstrated that the adjustable intensity of heat removal from an ingot, as well as the addition of external excess pressure on the hardening melt, could be used as such tools. In the study, to obtain ingots with a minimum level of chemical heterogeneity, it would suffice to provide the following conditions for the curing of the alloy: a value of the alloy crystallization speeds at the level of Rcr ≥ 9·10–2 mm/s, or external pressure on the free surface of ingots Рext. ≥ 135 kPa. The industrial implementation of the reported results could make it possible to improve the technology of obtaining large blacksmith ingots, provide savings in materials and energy resources, increase the yield of a suitable metal, and improve its quality

В работе рассмотрена усовершенствованная технология нанесения на насосно-компрессорные трубы (НКТ), в том числе и на резьбовые соединения, диффузионного железоцинкового покрытия нового поколения с высокими показателями по коррозионностойкости и износостойкости. Комплексными исследованиями образцов оцинкованных НКТ подтверждены их высокие качественные характеристики и соответствие стандартным требованиям для различных условий эксплуатации. Авторами подготовлен проект технологической инструкции по интерметаллидному диффузионному цинкованию НКТ, составлен перечень необходимого оборудования для нанесения диффузионного цинкового покрытия на насосно-компрессорные трубы. Разработаны рекомендации по применению НКТ с диффузионным железоцинковым покрытием на предприятиях нефтегазодобывающего комплекса Чеченской Республики и РФ. The paper considers an improved technology for applying a new generation diffusion iron-zinc coating with high corrosion resistance and wear resistance to pumping and compressor pipes (TUBING), including threaded connections. Comprehensive studies of galvanized tubing samples have confirmed their high quality characteristics and compliance with today’s requirements for various operating conditions. The authors have prepared a draft of technological instructions for intermetallic diffusion galvanizing of tubing, compiled a list of necessary equipment for applying diffusion zinc coating to pumping and compressor pipes. Recommendations have been developed for the use of tubing with diffusion iron-zinc coating at oil and gas production enterprises of the Chechen Republic and the Russian Federation.