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Results of computational experiments on studying multiphase flow and interphase interaction in the volume of an industrial 50-ton tundish of a continuous caster, including when blowing with argon through bottom blowing blocks, are presented. A mathematical model has been developed that makes it possible to predict the dynamics of melt mixing at a given casting speed. The pattern of influence of the layout of the ladle’s working space on the area of “stagnant zones” in the ladle volume has been found.

The procedure of cooling ingots in continuous-casting machines affects both the reliability and productivity of the equipment and the quality of ingots obtained as a result. Insufficient heat exchange between the liquid metal and the wall of the mold leads to a decrease in the thickness of the solid shell of the ingot promoting the formation of surface defects and, in the process of pulling of the ingot out of the mold, leads to the appearance of emergency ruptures. At the same time, excessive heat transfer leads to an increase in the thickness of the solid shell, which results in the redundant shrinkage of the ingot surface accompanied by the formation of a gap between the solid shell of the ingot and the walls of the mold. The appearance of a gap filled with air leads to a sharp decrease in the intensity of heat transfer and accelerates the process wear of the copper walls of the mold. There exists a design of the copper walls with end bevels (protrusions, shoulders, and “whiskers”), which makes it possible to decrease the normal component of forces formed in the process of wear, lower the temperature gradient and the level of stress concentration in the corners of the ingot by increasing the angle from 90 to 135°, and also make the thickness of the “stocking” of solid crust in the corner of the mold closer to the perimeter of the crystallizer. However, the thermal state of the formed ingot for the indicated design of the crystallizer remains poorly studied. We develop a mathematical model and an algorithm for the evaluation of the thermal state of an ingot (with rectangular cross section and angles beveled at 45°) placed in the mold. This enables us to analyze the process of solidification of the ingot in a slab continuous-casting machine. Based on the created mathematical model and the proposed algorithm for solving the boundary-value problem, we created a computer program “Simulation of slab hardening.” By using the results of computer simulations, we obtained the diagrams of temperature distributions in the cross section of the ingot at the exit of the mold of the continuous-casting machine with straight or beveled corners. We also present the dependences of variations of the thickness of solid crust along the height of the crystallizer. The results obtained in the present work can be used to choose the rational shape and the rate of taper of the mold walls in a slab continuous casting machine guaranteeing the decrease in the size of the gap between the solid crust of the ingot and the working surface of the mold.

Continuous casting machine rolls and hot rolling mill work rolls are susceptible to surface cracking under dynamic loading. The fracture resistance of homogeneous metal compositions used for their manufacture and hardfacing is determined by the work of crack initiation. This is evaluated by separating the work of crack initiation from the work of crack propagation. Research on the dynamic fracture process of heterogeneous multilayer composites hardfaced on hot rolling mill work rolls confirmed that crack arrest at the interface between strong and ductile layers occurs by a delamination mechanism, ensuring high impact toughness. Furthermore, it was found that homogeneous steel compositions with cast and plastically deformed structures used for the manufacture and hardfacing of continuous casting machine rollers and work rolls exhibit a linear relationship between fatigue crack growth rate and stress intensity factor range. This linear relationship deviates in heterogeneous hardfaced metal structures, where the fatigue crack propagation rate varies and exhibits regions of abrupt deceleration. Similar behavior is observed in welded joints of steels with different compositions and mechanical properties. The study also revealed that in cases where there are significant differences in the structure and thermophysical properties between the hardfacing layer and the base material of continuous casting machine rollers, a sharp drop in the level of axial tensile stresses at the fusion boundary leads to the arrest of surface fatigue cracks. In the absence of such a drop in stress, the crack changes direction and slows down, but does not stop. In addition, the application of variable composition hardfacing technology to hot rolling mill work rolls not only reduces uneven wear along the roll barrel, but also increases resistance to surface cracking.

The improved technology of position control and alignment of the continuous casting machine (CCM) equipment based on high-precision online geodetic measurements is considered. The mathematical model for the technological axis of the continuous casting machine, the technique of the rational alignment of the machine’s equipment and the software implementing this technique are proposed. The application experience of the developed technique for control and aligning the equipment of continuous casting machines of different types is shown. The data on the efficiency of the technique for continuous casting machine equipment and its impact on the quality of a continuously cast ingot are presented.

Mold breakout is one of the significant problems in a continuous casting machine (caster). It represents one of the key areas within the steel production facilities of a steel plant. A breakout event on a caster will always cause safety hazards, high repair costs, loss of production, and shutdown of the caster for a short while. In this paper, a logic-judgment-based mold breakout prediction system has been developed for a continuous casting machine. This system developed new algorithms to detect the different sticker behaviors. With more algorithms running, each algorithm is more specialized in the other behaviors of stickers. This new logic-based breakout prediction system (BOPS) not only detects sticker breakouts but also detects breakouts that takes place due to variations in casting speed, mold level fluctuation, and taper/mold problems. This system also finds the exact location of the breakout in the mold and reduces the number of false alarms. The task of the system is to recognize a sticker and prevent a breakout. Moreover, the breakout prediction system uses an online thermal map of the mold for process visualization and assisting breakout prediction. This is done by alerting the operating staff or automatically reducing the cast speed according to the location of alarmed thermocouples, the type of steel, the tundish temperature, and the size of the cold slab width. By applying the proposed model in an actual steel plant, field application results show that it could timely detect all 13 breakouts with a detection ratio of 100%, and the frequency of false alarms was less than 0.056% times/heat. It has the additional advantage of not needing a lot of learning data, as most neural networks do. Thus, this new logical BOPS system should not only detect the sticker breakouts but also detect breakouts taking place due to variations in casting speed and mold level fluctuation.

The paper presents the results of the study aimed at solving the problem of rational distribution of electric drives of pulling rollers along the technological line of a continuous casting machine and selecting a minimum number of pulling rollers in different areas of the secondary cooling zone. The research includes construction and ranking the criteria for distribution of drive rollers along the production line of the continuous casting machine; development of methods and algorithms for calculating the required distribution of load moments on pulling rollers and distribution of electric drives of pulling rollers along the secondary cooling zone in three modes of the electric drive operation of the pulling-straightening device: containment of the dummy bar in the preparatory casting mode of the continuous casting machine; pulling the dummy bar with the head of the ingot at the initial stage of pouring the metal; withdrawal of the ingot in the working mode of casting. Theoretical studies were carried out with the use of analytical and numerical methods for solving algebraic equations, methods of structural modeling. Experimental studies were carried out in the conditions of a large metallurgical enterprize with subsequent processing of the obtained data by statistical methods. The technical and economic analysis of the options of the electric drive execution of the pulling-straightening device showed that due to a significant reduction in the number of electric drives of pulling rollers, the payback period of replacement of a group scheme of power supply of electric motors to an individual one in new continuous casting machines decreases from 5.8 to 7.8 years with the traditional distribution of pulling rollers along the secondary cooling zone to 2.8–3 years with their rational distribution, calculated by the developed methods. The results of the work were used in the design of a slab machine for continuous casting of curvilinear strands intended for casting wide slabs up to 2.5 m. According to the proposed method, the number of electric drives pulling the rollers was reduced to 56.

The influence of the electromagnetic mixing (EMM) of liquid metal in the mold of the continuous casting machine on its thermal work, the formation of the structure and properties of cast billets are investigated. The influence of the current and frequency of EMM on the mechanical properties, macro-and microstructure of round and square sorted billets was established.

Improvement of macrostructure indicators of slabs during continuous casting of steel on a thin-slab machine of the sheet-rolling shop of Vyksa Steel Works JSC was achieved by introducing the latest programs into the automation system for the soft reduction process.

Increase in efficiency of a continuous casting machine is directly related to reduction of a shutdown period to repair and to eliminate accident consequences. One of the most widespread and severe accidents on the machine is the strand shell breakout under a mold. This article presents results of development and operation of the intelligent system for prediction of liquid metal breakouts under the mold of slab continuous casting machines. The most significant scientific results of the study are: mathematical model of copper mold wall temperatures values distributed on the mold perimeter, diagnostic criteria for strand shell sticking in the mold, and techniques and algorithms of strand shell sticking in the mold. Applying the listed results at development of continuous casting machine automation systems allow to reduce the number of accidents on continuous casting process, what is very important for the steel industry.

—Industrial continuous casting machines in Russia mainly employ imported electromagnetic-stirring systems located outside the mold. In case of breakage, the stators of such stirreres must be sent back to the manufacturer for repair. To decrease import dependence, an electromagnetic-stirring system that may be completely dismantled has been developed at the Russian Research Institute of Metallurgical Machinery. This design permits preventive maintenance and repairs in the plant’s electrical shop, without the need for expensive materials or equipment.