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Целью работы является повышение конкурентоспособности и расширение номенклатуры продукции предприятия полного металлургического цикла за счёт совершенствования третьего передела. Были разработаны основные методики и сформулированы требования для внедряемых мероприятих по установке гидросбива окалины, автоматизации синхронизации клетей, системы измерения геометрии прокатываемого профиля, устройства ускоренного охлаждения проката и внедрение новых марок сталей., The aim of the work is to increase the competitiveness and expand the product range of the enterprise of the full metallurgical cycle by improving the third processing. The main methods were developed and requirements were formulated for the implemented measures for the installation of a hydraulic scale breaker, automation of the synchronization of stands, a system for measuring the geometry of the rolled profile, devices for accelerated cooling of rolled products and the introduction of new steel grades.

В настоящей выпускной квалификационной работе «Исследование процесса удаления серы из полупродукта на установке десульфурации в условиях АО «ЕВРАЗ НТМК» рассмотрено распределение серы по переделам металлургического производства АО «ЕВРАЗ НТМК» а также проведена работа по повышению стойкости фурмы установки десульфурации чугуна., In this final qualifying work " Study of the process of removing sulfur from a semi-product at a desulfurization plant in the conditions of JSC "EVRAZ NTMK", the distribution of sulfur in the metallurgical production processes of JSC" EVRAZ NTMK " is considered, and work is also carried out to improve the durability of the tuyere of the pig iron desulfurization plant.

The article considers the issues of sulfur removal in the ladle-furnace unit. The sulfur distribution coefficient depends on sulfide capacity of the slag, sulfur activity coefficient, oxidizing potential of the medium and equilibrium constant. The sulfide capacity CS of slags is one of the most important characteristics of refining capacity of the slags used in extra-furnace steel processing. One of the factors affecting the sulfide capacity is temperature. The formula was proposed showing the dependence of sulfide capacity on the optical basicity and temperature, in the temperature range of 1650 - 1400 °C and when the optical basicity Λ is not more than 0.75; the error of the presented formula does not exceed 6 %. The formula for calculating the optical basicity is proposed, which takes into account the influence of basic, acidic oxides and amphoteric oxide Al2O3 . It is shown that slags, completely consisting of a homogeneous phase, have an increased optical basicity of aluminum oxide. Heterogeneous slags have a reduced optical basicity of Al2O3 in comparison with homogeneous slags. Perhaps, this fact can be explained by the fact that in homogeneous slags there is a deficiency of the basic oxide CaO and in the conditions under consideration Al2O3 compound begins to exhibit more basic properties than acidic ones, thus, in homogeneous slags, the optical basicity of aluminum oxide is increased and approaches optical basicity of CaO oxide. Calculations carried out on the basis of real heats have shown that with an increase in the content of Al2O3 oxide in the slag, its optical basicity decreases. Known value of the optical basicity makes it possible to determine sulfide capacity of the slag, sulfur distribution coefficient between metal and slag, and, accordingly, final sulfur content in the metal. The research results have shown that it is advisable to apply the ionic theory of slags for the sulfide capacity determination. © 2021 National University of Science and Te

In this article the influence high — temperature Joule heating on microstructure aluminum and titanium electro-spark deposits was considered. Electro-spark procedure was carried on conventional parameters by means of rotating electrode atop surfaces sheet — samples of low carbon steel in air environment. Was fixed, that after electro-spark alloying by means of both electrodes formed hard deposits. For aluminum deposit, high — temperature heating perform it to whit more thick layer with low micro-hardness. In place former titanium deposit was appeared local small volumes of melting with dendrite structure and middle micro-hardness., В статье рассмотрено влияние высокотемпературного нагрева проходящим током на структуру электроискровых покрытий из алюминия и титана, нанесенных в воздушной среде на низкоуглеродистую сталь вращающимся электродом на типовых режимах. Установлено, что после электроискрового легирования обоими электродами формируется твердый слой. Для алюминиевого покрытия после высокотемпературного нагрева и охлаждения образуется более толстый белый слой с микротвердостью на уровне основного металла. На месте титанового покрытия выявляются участки плавления, более твердые по сравнению с основным металлом и имеющие дендритную структуру.

Experimental data test of heat treatment are presented in conditions of shop production of increased hardness grinding balls on EVRAZ-NTMK. Conditions for implementation of grinding balls heat treatment technological modes on the new ball rolling shop of JSC „EVRAZ-NTMK“ allows to obtain high grades hardness balls on the steel with lower proprties, which shows its significant potential., Представлены экспериментальные данные апробации технологических режимов термической обработки в условиях участка производства мелющих шаров повышенной твердости АО «ЕВРАЗ.НТМК». Условия реализации технологических режимов термической обработки мелющих шаров на новом шаропрокатном участке позволяют получать высокую твердость шаров на марках стали меньшего целевого назначения, что показывает его существенный потенциал.

This work features research findings on causes of deterioration occurring in ball-rolling rolls. The causes of such deterioration may originate not only in the excessive loads application and the use of bottleneck operating parameters but also in the specific process being implemented and the equipment used to heat-treat the rolling rolls. The deterioration occurring in roll flanges having a relatively small thickness was used to demonstrate that, to prevent the deterioration of ball-rolling roll flanges, the mill design must accommodate the minimum allowable flange widths obtained as a function of maximum allowable loads and the roll pass calculations. The next example of roll deterioration involved the use of a gas furnace to implement the heating stage of the quench hardening process for rolls made of 35KhGSA steel, which, as a result, developed roll deterioration. The use of rolls of the same steel grade, which were heat-treated in an arc furnace prior to being quenched, has been shown to deliver long-lasting positive results evidenced by many years of their operation. Rolls made of 5KhNM steel have also been shown to respond well to the heat treatment preceding the quenching process, but this time, the treatment was implemented in a gas furnace. © Published under licence by IOP Publishing Ltd.

The process of carburizing is well-studied and is one of the traditional processes of the thermochemical treatment of steel. The process has disadvantages such as high energy consumption, long exposure time, complicated processing of large products and surfaces. Electrospark deposition with a carbon electrode is proposed as an alternative process. The carburizing extent and the working layer depth can be increased when the process is used in the ultrasonic vibration field. A resonant vibration introducing circuit with a standing wave generated in the specimen tested is implemented to identify the influence of specific ultrasonic wave areas on the hardened layer formed. The highest carbon saturation of the surface layer was found in the standing ultrasonic wave oscillation node area, where cyclic stretching and compression of the medium contribute to the excess phases release. The carbon in the martensite estimated by the c/a ratio was 0.78% by weight. The highest cementite layer depth and transition zone size are in the ultrasonic wave antinode area, where the highest dynamic medium particles displacement is observed under the influence of vibrations. It is shown that the base metal structure component dispersiveness is responsible for the increased hardened layer depth. © Published under licence by IOP Publishing Ltd.

This article outlines modern approaches to the creation of roll passes for helical rolling mills for the production of grinding balls. The key feature is the roll design with continually varying parameters of its elements. Such elements include: flange width varying along the length of the roll; flange height, with a nonlinear function of flange rising; pitch of the helical groove which maintains constancy of the volume of the metal being deformed. Particular attention is paid to a new conceptual pass design for ball-rolling rolls with a variable groove depth, the prospects of which are connected with uniformity of reduction and the production of balls not only with the correct geometry, but also with a more homogeneous structure. The article shows functions of a continuously varying pitch of a helical groove of rolls with a constant and variable flange width, as well as with a variable depth of the groove. A practical test was conducted on ball-rolling rolls for production of balls with a nominal diameter 120 mm with continuously varying pitch. Experience has shown positive results both in reducing loads and in increasing the dimensional accuracy. © Published under licence by IOP Publishing Ltd.

Electrospark coating deposited on the surfaces of machine parts is a common surface hardening method. Hard materials are normally used for depositing to improve wear resistance or other properties. In this investigation electrospark deposition intended for use as micro-alloying of welds by deposition on to the surface of the base metal and in this case it remelts completely. Intense heating and destruction occurs before remelting, which changes the chemical composition of the melt. The aluminum and titanium coatings is shown to deteriorate at 500 to 650 C generating a liquid phase due to eutectic available in both metals in this temperature range. Most of titanium and aluminum oxidized at that. It is found that a solid layer, appears after electrospark depositing using both coatings. For aluminum coating, after high-temperature heating, a thicker white layer appears with the same microhardness level as that of the base metal, and a thin layer of partial decarburizing. Fusion sectors are detected in the titanium coating that are harder than the base metal and have a dendritic structure, followed by a thin zone of complete decarburization and quite an extended zone of partial decarburization. © Published under licence by IOP Publishing Ltd.

This article describes issues of sulfur removal in ladle furnace unit. First of all, metal desulfurization in ladle steel treatment units is achieved due to transition of sulfur to the slag phase. Coefficient of partition of sulfur between metal and slag is affected by sulfide capacity of slag, coefficient of activity of sulfur in the metal, oxidation potential of medium and reaction equilibrium constant of partition of sulfur between metal and slag. Temperature of liquid state in the ladle has significant impact on sulfide capacity of slag. Proposed calculation procedure based on provisions of ionic structure of slags allows evaluating a concentration of sulfur in steel on the basis of determination of coefficient of its partition between metal and slag. Optical basicity is suggested as criterion of refining property of slag, it has been shown that the amphoteric oxide Al2O3 is essential to calculation of this indicator. Its impact on sulfide capacity of slag is detected. © Published under licence by IOP Publishing Ltd.