Search

This paper proposes a novel intelligent scheduling method based on deep reinforcement learning (DRL) to solve the multi-objective steelmaking-continuous casting (SCC) scheduling problem, under time-of-use (TOU) tariffs for the first time. The intelligent scheduling system architecture is designed, and a mathematical model is established to minimise the total sojourn time and electricity cost. To effectively reduce production costs by avoiding peak periods of electricity consumption, the 'start time' of the system is generated based on the Markov Decision Process (MDP), and heuristic scheduling rules related to power cost are used as the action space, with corresponding reward functions designed according to the characteristics of these two objectives. To satisfy the continuous casting which is a particular SCC constraint, a backward strategy is developed. Additionally, a branching duelling double deep Q-network (BD3QN) is adapted to guide action selection and avoid blind search in the iteration process, and then applied to real-time scheduling. Numerical experiments demonstrate that the proposed method outperforms comparison algorithms in terms of solution quality and CPU times by a large margin. [ABSTRACT FROM AUTHOR]

To investigate the effect of the filter device on the cleanliness of molten steel and the flow field distribution within the tundish. The tundish filters were designed into five groups of pores with 20°, 25°, 30°, 35° and 40° elevation angles, and the flow field distribution and impurity removal rate of molten steel were calculated by Discrete Phase Model (DPM). The results showed that the removal rate of impurity in the molten steel could be significantly improved by using the tundish filter with elevation angle. When the elevation angle of the filter was 40°, the impurity removal rate reached 74.05%, and the flow field distribution would be more stable. The presence of the tundish filter caused the higher flow density of the molten steel before the filter inlet to decrease and become steadier after the filter, thereby enhancing the contact rate between impurities in the molten steel and the covering agent, ultimately achieving the highest impurity removal rate. [ABSTRACT FROM AUTHOR]

In the process of continuous casting, the movement of inclusions plays a pivotal role in determining the grade of the final steel product. The present study focuses on the dynamic behavior of inclusions within the mold during continuous casting in the presence of a novel-designed hexa-furcated nozzle (HFN). Simulations were conducted to investigate the interaction between inclusion movement with casting speed and submerged entry nozzle depth (SEN), specifically focusing on the effects of the HFN. Using a water model validation approach, the study simulated the movement of inclusions under various casting conditions, replicating real-world scenarios encountered in steel production. The experiments revealed significant insights into how the introduction of the HFN influences the behavior of inclusions within the mold, shedding light on potential strategies for optimizing casting parameters to diminish inclusion shortcomings in the final steel product. [ABSTRACT FROM AUTHOR]

The objective of this paper is to present the effect of horizontal continuous casting parameters on macrosegregation and its effect on microstructures, textures, mechanical properties, and electrical resistivity of Cu–Mg alloy rod. By increasing the pulling distance and intermittent extraction time, chemical macrosegregation was observed along the longitudinal section of the cast rod, which reached a distance of 40 mm. Three areas were identified along the length of the material, especially at high pulling distance: with decreasing, quasi-stable, and increasing Mg concentration area. As the pulling distance increased, the difference in the observed extreme values of Mg concentration increased. Two distinct zones of different grain size were also observed. The first zone was formed of large columnar grains with a preferred direction of solidification ⟨ 100 ⟩ inclined to the axis of the wire, followed by a second zone formed of small grains of random texture. Consequently, difference in resistivity occurred from one zone to another and the resistivity increased from 37.5 to 41 nΩm. Likewise, the hardness varied between the values of 90 up and 110 Hv. The most homogenous chemical composition was obtained with up to 6 mm of pulling distance and up to 3 seconds of intermittent extraction time. [ABSTRACT FROM AUTHOR]

As representative compositions of the mold flux used in the continuous casting of steel, the temperature and composition dependence of the thermal conductivity of alkali silicate glasses and melts was investigated in the range of 300–1700 K using molecular dynamics (MD) simulations. MD simulations can exclude disturbances such as radiation, convection, and impurities, and extract only the effect of phonons on the thermal conduction. Thermal conductivity determined by the laser flash (LF) method was reported to be three times higher than that obtained by the unsteady hot wire (HW) method in the high‐temperature range of 1250–1550 K for 33.3Na2O–66.7SiO2 (mol%). This study shows that (1) the thermal conductivity estimated by MD simulations was closer to the experimental value of the LF method than those of the HW method above 1200 K, which suggests that the LF method is reliable and that the effect of radiation on the thermal conductivity is not significant. (2) The decrease in the thermal conductivity measured by the LF method in the range of 1250–1550 K was attributed to the decrease in the bulk modulus of the 33.3Na2O–66.7SiO2 melt. (3) In a series of Na2O–SiO2 melts, the sound velocity calculated by MD decreased with increasing Na2O content, which is consistent with Shiraishi's ultrasonic wave measurements. [ABSTRACT FROM AUTHOR]

The heat distribution and wear threat of the plate crystallizer used in continuous casting production are different in each area, and a single-thickness coating is unable to fulfill the requirements of all areas. To extend the service life of the crystallizer, a high hardness WC-Cr3C2-Ni thickness gradient wear-resistant coating was prepared on the inner wall of the crystallizer via the HVAF (High-Velocity Air Fuel) spraying technology. In cyclic thermal shock environments, the thermal shock resistance of planar coatings decreased with the thickness. The coating with a thickness of 100 μm exhibited the best thermal shock resistance, with up to 25 cycles at 800 °C thermal shock. In high-temperature wear experiments simulating actual service environments, the 300 μm coating, which owned the worst theoretical thermal shock resistance, was well bonded to the substrate and exhibited good serviceability. Comprehensive experimental results showed that the WC-Cr3C2-Ni coatings deposited by HVAF were stable in practical long-cycle production. The coating preparation process proposed in this paper has been applied in domestic steel mills, effectively extending the working cycle of the production line and improving economic efficiency. This study will provide a theoretical basis for the selection and preparation of surface coatings for continuous casting crystallizers and other structures in complex service environments. [ABSTRACT FROM AUTHOR]

Copyright of Foundry Technology (1000-8365) is the property of Foundry Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Foundry Technology (1000-8365) is the property of Foundry Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Fe-15Mn-10Cr-8Ni-4Si alloy, which has excellent low-cycle fatigue durability, was developed as a core material for steel-based vibration dampers that are effective against large-amplitude, long-period earthquake motions, and was put into practical use in 2014. However, manufacturing using small-scale equipment was expensive, so the authors tried manufacturing using stainless steel continuous casting facility and rolling facility, and succeeded in mass production. The authors also developed welding materials and welding techniques to assemble a buckling restraint brace damper with flat plasticizing section and one with cruciform plasticizing section, and successfully put these two types of brace dampers into practical use. The alloy plate has been recognized as an industrial product that can be manufactured with stable quality, and has been approved by the Minister of Land, Infrastructure, Transport and Tourism as a steel material for construction. [ABSTRACT FROM AUTHOR]

Copyright of Metal Working (1674-165X) is the property of Metal Working Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The flow field, fluctuation of interface between steel and slag, distribution and capture of argon gas and solidified shell thickness in molds with different nozzles with two or three holes are studied with high-temperature quantitative velocity measurement and numerical simulation. The simulated results of surface velocities are in good agreement with the high temperature measurement results under different argon gas flow rates in the mold with the two- and three-hole nozzles. Compared to the mold with the three-hole nozzle, in the mold with the two-hole nozzle, the surface velocities of molten steel, fluctuation of interface between steel and slag, and inclination angles of jet flow of molten steel are larger, while the capture ratio of argon gas bubbles and solidified shell thickness are smaller under the same continuous casting parameters. When the argon gas flow rate is increased from 4 L/min to 8 L/min, the inclination angle of jet flow and capture ratio of argon gas decrease from 21.8° to 16.7° and increase from 0.12% to 0.27% in the mold with the two-hole nozzle. Those decrease from 20.5° to 11.3° and increase from 0.44% to 0.49% in the mold with the three-hole nozzle, respectively. [ABSTRACT FROM AUTHOR]

Fe-Mn-Al-C high-manganese and high-aluminum (high-Mn and high-Al) steel has the characteristics of high strength at room temperature and low temperature, good fatigue performance, high elongation, and good energy absorption in collisions. It is a lightweight advanced steel material with great potential for structural parts in automobile, transportation, military, and other fields. At present, there are serious surface quality defects and drastic slag–metal reactions during the continuous casting production, which hinder the efficient production of high-Mn and high-Al steel. The paper focuses on the development and challenges of continuous casting of high-Mn and high-Al steel. Firstly, the current development status of high-Mn and high-Al steel is reviewed. Then, combined with the production practice of continuous casting, difficulties and key points of control of high-Mn and high-Al steel are introduced from three aspects of non-metallic inclusion control, casting superheat control, and cooling process control. Finally, the challenges currently encountered in the production different types of mold fluxes are summarized and analyzed, and the key points for the development and application of a new type of titanium-containing continuous casting mold flux for high-Mn and high-Al steel are discussed. It is expected to provide a useful reference for improving the quality of Fe-Mn-Al-C high-Mn and high-Al steel for automotive and realizing its efficient and large-scale continuous casting production as soon as possible. [ABSTRACT FROM AUTHOR]

The solidification structure and segregation behavior in 20Mn2 alloyed steel from continuously cast billet with different casting speed (2.0, 2.4, 2.7 m/min) has been investigated, and the dendrite evolution and solute enrichment characteristics in the billet at high speed casting has been revealed. It is found that the deflection angle in the columnar dendrite induced by M-EMS decreases as withdraw speed increases, mainly due to the decrease in the average stay time in the stirring zone instead of the increase of steel flow rate, indicating the effect of M-EMS on the homogeneity of temperature and promotion of free nucleus formation reduces. The equiaxed ratio in the billet increases as casting speed increases from 2.4 to 2.7 m/min, attributed to the F-EMS acting as S-EMS to stimulate the formation of nucleus. The alignment of equiaxed zone in the case of 2.4 and 2.7 m/min is much better than that in 2.0 m/min, due to the weakening effect of M-EMS and strengthening effect of early F-EMS, together with the increase of superheat. The center segregation in the billet shows no obvious change as casting speed increases from 2.0 to 2.4 and 2.7 m/min, and low superheat, appropriate F-EMS and F-EMS working as S-EMS is the explanation for different trials respectively. The spot segregation in the billet deteriorates as casting speed increases, involving the increase in the size, number and solute content. The most severe solute enrichment is in the vicinity zone where fine dendrite and coarse dendrite contact. The countermeasures to improve the center quality of continuously cast billet at high speed is proposed. Medium superheat, strengthened M-EMS, intense secondary cooling, appropriate S-EMS and F-EMS are beneficial for most steels. [ABSTRACT FROM AUTHOR]

In the process of continuous casting, the slab temperature is a particularly crucial production parameter. However, it is still being monitored on the surface of the slab. At present, the prediction of slab temperature using machine learning models is not feasible due to the lack of internal temperature data from actual production. In this paper, a prediction method based on DNNs algorithm integrating numerical simulation and SHAP analysis is proposed to monitor the temperature field of continuous casting slab in real-time. The dataset comprises 6 input features and 5 output features. Following data preprocessing, four distinct machine learning models were developed employing DNNs, SVM, XGBoost, RF algorithms to individually predict the temperature of the slab. The DNNs model is selected as the optimal model according to the performance comparison using performance parameters such as MAE, MSE, and R2. SHAP value is calculated for the sensitivity analysis of the influence of the characteristic parameters of DNNs prediction model on the prediction results. The experimental results indicate that the prediction model has an average success rate of 96.48 pct within a temperature accuracy of ± 20 °C. Moreover, the resident time, the amount of internal side water within the slab, and the internal side heat transfer coefficient of the slab have the most significant impact on the model. This study introduces a novel method for establishing machine learning models with machine learning techniques. [ABSTRACT FROM AUTHOR]

The stable control of mold level is a key link in the production of high-quality continuous casting slabs. Periodic mold level fluctuation (PMLF) is common during the continuous casting process, and the abnormal PMLF has significant harmful effects on surface quality of slab. This article proposed an analysis and control method for abnormal PMLF. First, the finite impulse response (FIR) filter and fast Fourier transform (FFT) were used to remove noise interference in PMLF data and highlight the fluctuation characteristics of PMLM. Then, considering that uneven solidification has a significant impact on abnormal PMLF, the influence of chemical composition on the equilibrium Fe-C pseudo-binary diagram was calculated by Thermo-Calc software. Furthermore, roller diameter, roller spacing, casting speed, and chemical composition were chosen as the prediction indicator to predict the quality of PMLF. Random forest (RF) model shows good performance in predicting PMLF; the prediction accuracy of RF model is 92.76 pct, which is 21.39 pct higher than that of GA-BP model. Finally, the Feedforward fuzzy PID (F2FPID) controller designed in this article was used to eliminate abnormal PMLF. The average range of mold level fluctuation under the PID controller is ± 6.8 mm, while under the F2FPID controller, the average range of mold level fluctuation is ± 1.1 mm. And the F2FPID controller owns a lower overshoot of 0.48 pct and an adjusting time of 1.52 seconds, which are 94.8 pct and 59.5 pct, respectively, lower than those of the PID controller. [ABSTRACT FROM AUTHOR]

To avoid coarse crystallization of CaO–SiO2–Al2O3 inclusions during the solidification stage of continuous casting process, the effect of MgO on crystallization behavior of these inclusions is investigated. The single hot thermocouple technology experiment results show that the low melting point CaO–SiO2–Al2O3 inclusions do not easily crystallize during the solidification stage. However, with increasing the MgO content from 4.5 to 15.7 wt pct, the initial crystallization temperature of inclusions increases from 1376 K to 1431 K (1103 °C to 1158 °C) and the crystallization ratio increases from 35.45 to 100 pct. The crystallization ability of the inclusions can be predicted by the initial crystallization potential and the viscosity at the melting point. With increasing the MgO content from 0 to 15.7 wt pct, the initial crystallization potential of the inclusions increases from 0.28 to 0.87 and the viscosity of the inclusions at the melting point decreases from 4.47 to 0.56 Pa s. The higher the initial crystallization potential and the lower the viscosity near the melting point, the easier the crystallization of the inclusions occurs. Al2O3 mainly acts as the network former and participates in the construction of the network structure. With the increase of MgO content, the crystallization ability of inclusions increases gradually, which is mainly related to the increase of melt structure depolymerization. [ABSTRACT FROM AUTHOR]

Solidification end reduction is an effective approach to control the central porosity during continuous casting of round bloom, although it is not widely reported. In the present work, a three-dimensional finite element model has been developed with coupling heat transfer and mechanical deformation for a φ690 mm continuously cast round bloom, and verified by the surface temperature, shrinkage zone width, reduction crack location, and deformed contour shape. It is found that the contact width between roller and the bloom increases with the increase of reduction amount and approximately in a parabolic relationship. To cover the whole range of the shrinkage zone, the total reduction amount should not be smaller than 25 mm as the width of the shrinkage zone is about 120 mm. The bulge width along the horizontal direction during reduction increases as the total reduction amount increases, and the relationship can be fitted by a parabolic equation. The reduction thickness in the shrinkage zone is larger when the reduction amount is higher, and it also follows parabolic relationship. The deformation in the shrinkage zone is more obvious when the reduction is conducted before crater end. The reduction efficiency for φ690 mm round bloom before solidification is between 20 and 30 pct, while after solidification is roughly between 12 and 20 pct. It increases with the increase of apparent reduction amount, mainly related to the increase of the strain rate. The deformation of the shrinkage zone in φ690 mm round bloom with 30 mm apparent reduction in continuous casting and hot rolling has been compared. The equivalent strain in the shrinkage zone of the round bloom in continuous casting is about 0.047 to 0.052, while that in hot rolling is about 0.031 to 0.036, indicating the reduction efficiency of the former is about 1.5 times higher than the latter. [ABSTRACT FROM AUTHOR]

During steel solidification, solute element segregation at dendrite boundaries intensifies the precipitation of MnS inclusions. The morphology, dimensions, and spatial distribution of these precipitates influence the high-temperature thermoplasticity of continuously cast slabs. Variations in the equilibrium partition coefficients (ki) of different cooling phases in Q355 microalloyed steel were investigated using thermodynamic calculations. To obtain accurate parameters, the thermodynamic behavior of the continuous casting process was simulated using Marc finite element software for thermal history data at each node of the cooling process. A real-time constant cooling rate model was established, and four different rates were selected to verify the model. Model predictions and observations demonstrated strong agreement, with an error range of 2.2 to 5.2 pct. A method for calculating variable cooling rates was proposed. Based on the heat transfer model, a real-time variable cooling rate model was established and high-temperature confocal laser scanning microscopy (HT-CLSM) was used for observation of the solidification process. This prediction model can effectively characterize MnS precipitation and growth and the effects of casting speed and superheating on the particle size distribution of MnS inclusions. This study provides a rapid and accurate method for predicting MnS precipitation, helpful for optimizing the process of continuous casting. [ABSTRACT FROM AUTHOR]

The excellent water-cooling structure contributes to achieve efficient and reasonable heat transfer in the mold, which is essential for achieving the ultra-large beam blank continuous casting (ULBBCC). Therefore, this work designed different ultra-large beam blank mold (ULBBM) which were composed of three wide face copper plates with different water-cooling structures and two narrow face copper plates with different water-cooling structures, on the basis of which a three-dimensional heat transfer model of the copper plate coupling with the cooling water flow in the water-cooling structure was developed with the consideration of fluid-solid coupling interaction. Then, the accuracy of the model was verified by comparing the model-predicted and measured water temperatures. Finally, the focus is comparing the heat transfer behavior of the mold under different water-cooling structures, as well as the temperature and flow evolution of the cooling water, and the most optimal water-cooling structure was proposed. The results show that the water-cooling structure of water slots with semicircular roots (Mold II) contributes the narrow face copper plate of ULBBM to obtain excellent temperature uniformity and achieve homogenization of heat transfer. The water-cooling structure of small hole water channel with a diameter of 10 mm (Mold III) decreases the maximum temperature at the fillet of wide face copper plate of ULBBM to 582.9 K and the maximum circumferential temperature difference near the meniscus to 103.3 K, and which contributes the wide face copper plate to obtain higher temperature uniformity and lower fillet temperature, and achieve homogenization of heat transfer. [ABSTRACT FROM AUTHOR]

Based on our previously proposed three-phase solidification model, a comprehensive analysis on the impact of the only electromagnetic stirring (EMS) and combined EMS on the microscopic structure evolution and solute segregation behavior in a 500 mm diameter 42CrMo steel of continuously cast round bloom. The results indicate that M-EMS has a notable impact on expediting the dissipation of superheat, enhancing the initiation of grain formation, and enlarging the equiaxed region. The percentage of equiaxed grains increased from 59.26 to 63.37% with the increment in current intensities of M-EMS from 250 to 350 A. However, higher M-EMS current intensities were found to enhance local positive segregation in the transition zone between columnar and equiaxed grains. The impact of M-EMS on improving center positive segregation was minimal, as the ratio of center positive segregation remained consistently around 1.17. Furthermore, the implementation of F-EMS demonstrated its effectiveness in reducing center positive segregation. The ratio of center positive segregation decreased from 1.14 to 1.10, when the current intensity increases from 150 to 250 A. However, it should be noted that F-EMS alone did not contribute to the expansion of the equiaxed zone. On the other hand, when M-EMS was combined with F-EMS (referred to as combined EMS), it showed potential in mitigating center segregation during continuous casting round blooms. The benefits observed with M-EMS in terms of promoting grain nucleation and expanding the equiaxed grain zone were also evident in this combined EMS process. Furthermore, a notable enhancement in the equiaxed grain ratio up to 60.13% was observed combined EMS models were simultaneously employed during continuous casting of round blooms. And, there was a reduction in center segregation ratio for round blooms to as low as 1.09. [ABSTRACT FROM AUTHOR]

The slag-metal reaction between traditional CaO-SiO 2 -CaF 2 -Na 2 O-based slag and high-titanium steel deteriorates the performance of the mold flux, negatively affecting the surface quality of the slab and causing issues in continuous casting. To maintain the stability of slag properties after the slag-metal interaction, BaO and Li 2 O were added to the mold flux as a potential new slag system of the BaO-CaO-SiO 2 -TiO 2 -CaF 2 -Li 2 O-Na 2 O seven-component slag for the continuous casting of high titanium steel. In this study, the effects of the BaO/CaO ratio on the structure and properties of the seven-component slag were examined using molecular dynamics simulation and Raman spectroscopy, and the effect of the BaO content on the amphoteric behavior of TiO 2 was also investigated. With the gradual substitution of CaO by BaO, the melt's basicity increases, and TiO 2 transforms from acidic TiⅤ to alkaline TiⅥ. Simultaneously, the addition of BaO promotes the conversion of O b into O f and O nb , resulting in a simplified melt structure. The continuous increase in content of structural units Q Si 0 and Q Si 1 , along with the continuous decrease in content of Q Si 3 and Q Si 4 , further elucidates this phenomenon. Hence, it can be inferred that BaO primarily functions as a depolymerizing agent within the network structure of the melt. [ABSTRACT FROM AUTHOR]

Since most hot and cold metal-forming processes originate from various casting processes, it is important to test their susceptibility to the deformation of new materials. Cast rods of CuMg alloys with a Mg content of 2, 2.4, 2.8, 3, 3.2, 3.6, and 4 wt.% were obtained in the continuous casting process with pure copper as a reference material in order to obtain information on the material's ability to withstand 50% deformation. The materials in the as-cast state were subjected to solutioning, cold drawing, and recrystallization. After each process, samples were taken and subjected to upsetting tests with 50% deformation applied in a single operation. Additionally, materials in the as-cast state were subjected to upsetting tests at 700 °C. The hardness and electrical conductivity of each sample were analyzed. Selected samples were subjected to microstructural analysis. The obtained results show an increase in hardness from 46 HB to 90–126 HB, and a further increase to 150–190 HB with a quasi-linear decrease of electrical conductivity, which proved the influence of solid-solution and strain hardening, respectively. The microstructural analysis proved that such deformation does not cause microcracks. Furthermore, in the case of CuMg up to 3 wt.% of Mg, the alloying additive completely dissolved after solutioning. [ABSTRACT FROM AUTHOR]

5356 aluminum alloy welding wire is widely used in automotive, aerospace, and marine, due to its excellent corrosion resistance, high strength-to-weight ratio, and excellent weldability. The properties of aluminum alloys are primarily determined by their microstructure. This study investigates the microstructure evolution, mechanical properties, and texture of 5356 aluminum alloy welding wire produced using the continuous casting direct rolling (CCDR) method. The results show that continuous rolling led to an increased generation of dislocations in the matrix, and dynamic recovery plays an important role in reducing dislocation density. As a result of dynamic recovery, the microstructures of 3RPs consist of extensive deformed grains and numerous substructures. The continuous casting direct rolling textures are characterized to be cube and shear textures. After 10 rolling processes, the 5356 aluminum alloy welding wire shows a highest tensile strength of 365 MPa with a lowest elongation of 8.8%. This research provides theoretical guidance to produce high-performance 5356 aluminum alloy welding wires, paving the way for their more efficient and reliable applications. [ABSTRACT FROM AUTHOR]

During high-speed continuous casting, the effect of secondary cooling on the quality of the billet is more obvious, and the possibility of quality problems is higher. This study takes the continuous casting machine producing 165 mm × 165 mm billet as the research object. The six different secondary cooling schemes are designed with the 4.5 m/min casting speed. By comparing the shell deformation, surface stress, surface temperature recovery, and metallurgical lengths at different secondary cooling schemes, the secondary cooling scheme applied in the high-speed continuous casting process is selected. The results show that the surface temperature recovery and stress of the billet in Scheme 1 are higher than those of other cooling schemes. The metallurgical length and shell deformation of the billet in Scheme 4 are higher than those of other cooling schemes. In Schemes 2, 3, 5, and 6, the shell deformation of Schemes 3 and 5 is higher than that of Schemes 2 and 6. In Schemes 2 and 6, the maximum surface central stress of the continuous casting billet in the secondary cooling zone is 36.3 MPa and 31 MPa, respectively. Scheme 6 is used as the secondary cooling scheme of high-speed continuous casting in this study. The water quantity in secondary cooling zone 1 ~ 5 segments of Scheme 6 is 28 m3/h, 31 m3/h, 16 m3/h, 10 m3/h, and 6 m3/h, respectively. Finally, the industrial trial is carried out, which proves that Scheme 6 can be applied to high-speed continuous casting. [ABSTRACT FROM AUTHOR]

To achieve the desired superheat of molten steel during the continuous casting process, optimization of process parameters such as molten steel temperature in ladle furnace, casting speed, and baking temperature is necessary. Therefore, obtaining the superheat corresponding to these process parameters in advance is particularly important. To address this issue, a model for predicting the temperature of molten steel in the tundish during continuous casting is designed. The model adopts a combined modeling approach of mechanistic model and data model. To address the issue of the mechanism model's inability to capture the variation of the lining's thermal parameters, this article improves the traditional physics-informed neural network (PINN) algorithm. It combines the constraints from both the forward and inverse problems, allowing for obtaining solutions to the equations while capturing the variation of equation parameters. Actual data from multiple casting sequences at a steel plant are collected to validate the accuracy and interpretability of the model. The results show that the error of the model is about 2.1k which has better accuracy compared to pure mechanistic model and pure data model. Additionally, it can capture the variation patterns of tundish lining thermal parameters under different operating conditions. Therefore, the model designed in this article can provide both profound physical interpretation ability and more practical predictions of molten steel temperature. [ABSTRACT FROM AUTHOR]

An alloyed cast iron was prepared by horizontal continuous casting. To study the salt bath temperature on microstructure and mechanical properties, the alloyed cast iron was firstly austenitized at 950 °C for 3 h and then austempered in salt bath at various temperatures (250 ℃, 300 ℃ and 350 ℃) for another 3 h. The scanning electron microscopy (SEM), electron backscattered diffraction (EBSD), and X-ray diffraction (XRD) were employed to observe the microstructure and test the mechanical properties of the alloyed cast iron. Results show that the microstructure of the alloyed cast iron is mainly composed of acicular or feathery ferrite (bainite), retained austenite, carbide, and graphite. When austempered in salt bath at 250 ℃, 300 ℃ and 350 ℃ for 3 h, the volume fractions of retained austenite are 33.1%, 41.7%, and 57.2%, the thickness of acicular ferrite are 0.25 μm, 0.3 μm, and 0.8 μm. As the salt bath austempering temperature increases, the mechanical properties decrease due to the increase of the volume fraction of retained austenite and the thickness of acicular ferrite. The highest tensile strength of the alloyed cast iron is achieved when it is austempered at 250 ℃ in a salt bath. Under these conditions, the tensile strength of the alloyed cast iron can reach 1,429 MPa. Tensile test results indicate that the fracture mechanism is predominantly brittle fracture. [ABSTRACT FROM AUTHOR]

The continuous casting and continuous extrusion processes were used to prepare 6201 aluminum alloy wires. Electron backscattering diffraction, transmission electron microscopy, hardness, tensile, and conductivity tests were used to study the effects of Ni microalloying on the microstructure, mechanical properties, and conductivity of 6201 aluminum alloy. The results show that Ni microalloying refins the grain size of 6201 aluminum alloy in continuous casting, continuous extrusion and solid solution treatment states, which in turn improved the strength. During the aging process, Ni microalloying accelerated the age-hardening behavior of 6201 aluminum alloy, which increase the peak hardness and strength while retaining plasticity. But it decrease the electrical conductivity of the alloy because the Ni atoms always existed in the form of a solid solution, increasing the density of β"-precipitates and refined the size. The optimum yield and tensile strengths of 295. 33 MPa and 326. 12 MPa, respectively, are obtained by Ni microalloying and optimization of the heat treatment process. [ABSTRACT FROM AUTHOR]

The paper addresses the issue of early detection of steel ladle slag in the continuous casting of steel. In this study, the vibration method of slag detection was evaluated due to the high informative value of the vibration signal. The analysis is based on the variation in the character of the vibration acceleration signal of the protective tube manipulator of the continuous casting machine when slag enters the intermediate ladle. The envelope method of the vibration power spectrum was used to derive five empirical criteria for slag cut-off. In addition, these criteria included data on the molten mass in order to reduce the occurrence of false alarms. A generalized measure was developed to determine the performance quality of the criteria which was estimated to be 91.79%. This result validates the efficiency of these criteria and their suitability for testing in real production conditions. [ABSTRACT FROM AUTHOR]

A numerical simulation of a two-roll continuous casting machine has been performed. The influence of the key process parameters on the position of the end of solidification (called here solidification welding point: SWP), and on the stress state in the solidified strip have been analyzed. The stress and strain distribution in the rolling stage and the mechanism of the change of thermal stresses caused by air cooling on the edge crack were analyzed by the structural simulation in the plastic forming stage. The results show that the cracking tendency is the smallest when the cast-rolling temperature is 930 K, the heat transfer capacity of the roll is 3000 W/(m2 K) and the cast-rolling speed is 3.2 m/min. The equivalent strain at the edge of the cast-rolled sheet is higher than that in the middle, and cracks are more likely to occur. After passing through the roll gap, the thermal stress changes through three stages: transient, transition and stability, and the shrinkage along the width direction is much larger than that in the thickness direction. [ABSTRACT FROM AUTHOR]

In the current study, a measurement of the magnetic flux density in the second cooling zone was performed for a 1250 mm width and 200 mm thickness slab continuous casting strand generated by the electromagnetic stirring with varied current intensity and frequency. From the narrow face to the width center of the slab, the magnetic flux density showed a increased, decreased, increased to a peak, and finally decreased trend. The magnetic flux density was decreased from the wide side to the thickness center of the slab, while an increase occurred from the model top to the stirrer center along the casting direction. To broaden the measurement range of the electromagnetic stirring parameters, the electromagnetic field in the strand and stirrer was calculated based on the finite element method, and the current input was achieved using the node loading approach. The effect of the mesh density on the calculation accuracy was investigated, and it was found that the 20 mm cell size in the strand region and the 10 mm cell size in the coil conductor and the iron core were enough to achieve a good agreement between the calculation and measurement. The empirical equations, Bx = 0.165.f0.63.I−0.57.(–6870.x4–9700.x3–4260.x2–495.x + 90), By = 0.167.f−0.5.I0.45. (4272.y2 + 0.2733.y + 101.4), and Bz = 0.1724.f−0.5.I0.45.(0.0191.exp(24.16.z − 16.12.z2) + 2.3) were derived to estimate the local magnetic flux density based on measured values across the width of the slab and calculated values along the casting direction under diverse operational conditions. These equations hold practical significance in elucidating the spatial distribution of magnetic flux density within the strand region in the second cooling zone. [ABSTRACT FROM AUTHOR]

The effects of FetO on the characteristic melting temperature, viscosity, and structure of Na2O3-B2O3-CaO-SiO2-Al2O3 slag were investigated. Understanding the viscous behavior and structure of borate slag containing FetO can guide the design of mold powders for copper alloy casting. The melting temperature (Th) suddenly increased and exceeded 800 °C when the FetO content increased from 15 to 23 wt%. The viscosity changed significantly with increasing FetO content when the temperature was below 1050 °C. The slag structure exhibited a boron–iron anomaly. The viscosity of the Na2O3-B2O3-CaO-SiO2-Al2O3 slag gradually increased with increasing FetO content. When the content of FetO was low, sufficient oxygen in the slag promoted iron and boron to enter the network structure in the form of [FeO4] and [BO4], thereby reducing free oxygen and free [BO3]. As the FetO content exceeded a certain value, free oxygen decreased proportionally, and some iron ions existed in the form of [FeO6] with the network modifiers. Simultaneously, the amount of free [BO3] that is not bound to oxygen increased. Based on the optical basicity viscosity prediction model, the viscosity of borate slag with high iron content was predicted, and the M–O bond strength reflected by optical basicity was closer than the strength predicted for the network structure based on slag viscosity. [ABSTRACT FROM AUTHOR]

Surface flaw detection is one of the main problems of extra-thick slab. In practice, it is considered that the application of mold electromagnetic stirring (M-EMS) is an effective means to reduce the inclusions located at the subsurface of thick slab. The present study conducted numerical studies on the inclusion transports in an extra-thick slab continuous casting mold with the effects of M-EMS. The influences of M-EMS on the inclusion collision, coalescence and removal were revealed. The predicted results indicate that the majority of inclusions entering the mold are smaller than 20 µm. The application of M-EMS promotes the collision, aggregation, and flotation of these inclusions. When the inclusions entering the mold are larger than 30 µm, the flotation removal of inclusions significantly increases, and the collision and aggregation among inclusions decreases accordingly. Furthermore, the predicted results show that inclusions larger than 200 µm in size are unlikely to follow the downward flow into the lower region of the mold, with the primary removal location concentrated near the nozzle. Large-size inclusions have been quantitatively extracted from samples with and without M-EMS using galvanostatic electrolysis method. The results indicate that the inclusions of various sizes in the slab surface layer are reduced when M-EMS is employed. Notably, inclusions sized 50–150 µm show the most significant reduction, with their mass density decreasing from 38.17 mg/10 kg to 15.11 mg/10 kg. This demonstrates a substantial reduction in large-size inclusions on the slab surface layer following the introduction of M-EMS in the mold. [ABSTRACT FROM AUTHOR]

The pores in lotus-type porous copper are formed due to the difference in hydrogen solubility between the liquid and solid phases of copper. In a pressurized hydrogen atmosphere, hydrogen gas is released at the gas release and crystallization temperature, which is the melting point of copper. This study systematically analyzes the effects of process parameters, including hydrogen ratio, total pressure, and continuous casting speed, on the pore structure of lotus-type porous copper, with the aim of identifying the most critical process parameters for controlling pore diameter and density. Within the hydrogen ratio up to 50%, it was observed that as the hydrogen ratio increases, the pores tend to increase in porosity, and the pore diameter increases. As the hydrogen ratio increased from 25% to 50%, the pore diameter increased from 300 μm to 400 μm, while the pore density decreased from 3.3 N·mm−2 to 2.8 N·mm−2. As the total pressure increased, the pore diameter tended to decrease, and the pore density increased. Specifically, when the total pressure increased from 0.2 MPa to 0.4 MPa, the pore diameter decreased from 1100 μm to 400 μm, while the pore density increased significantly from 0.5 N·mm−2 to 2.8 N·mm−2. In addition, as the continuous casting speed increased, 30 to 90 mm·min−1, the pore diameter decreased from 850 μm to 400 μm, and the pore density increased from 0.7 N·mm−2 to 2.8. N·mm−2. Specifically, the increase in total pressure led to a decrease in Gibbs free energy and a reduction in the critical pore nucleation radius, which promoted pore formation and resulted in the creation of more, smaller pores. These results suggest that total pressure is the primary factor influencing both pore diameter and density in lotus-type porous copper. [ABSTRACT FROM AUTHOR]

Transverse corner cracks are among the most common defects in high carbon and high carbon micro-alloyed grade slab casting. Calculation and analysis were done to minimize the negative strip time of mold oscillation, which is responsible for reducing the depth of the oscillation mark formed on the slab surface. The value of negative strip time decreases with an increase in the frequency of mold oscillation. Based on the trial results, it was suggested that the oscillation proportionality be adjusted from 1.2 to either 1.25 or 1.3. This adjustment will reduce the depth of oscillation marks and the tendency to form transverse cracks. The transverse crack on the narrow face of the slab was examined for crack analysis and compositional analysis. Microstructural analysis revealed that the crack has no branching and consists of an iron scale inside it. Furthermore, it is observed that the crack propagates across the allotriomorphic ferrite grains. [ABSTRACT FROM AUTHOR]

During the continuous casting process, electromagnetic stirring (EMS) can control the flow pattern of the molten steel on the meniscus in the slab mould, while it is difficult to effectively control the entire molten steel. To this end, a novel composite magnetic field structure of EMS and electromagnetic braking (EMBr) is proposed, and the EMS–EMBr synergistic mechanism is analysed. The flow field of molten steel without a magnetic field is analysed. The magnetic field regulation strategy required to control the molten steel is clarified. The coil core structure layout of existing EMS is analysed. The action mechanism of EMS is studied through simulation, revealing the poor control effect of EMS on the molten steel under high casting speeds. Thus, a novel EMS–EMBr structure layout is proposed to enable the braking magnetic field to cover the key areas within the slab mould, ensuring that the main flow is effectively suppressed. On this basis, the effects of EMS–EMBr synergy and different process parameters on the flow pattern of molten steel are studied. The results indicate that the EMS–EMBr composite magnetic field structure proposed can more effectively control the molten steel, providing technical support for the development of electromagnetic metallurgical equipment. [ABSTRACT FROM AUTHOR]

To improve the service life of continuous casting crystallizer, the NiCo-ZrB2 coating was prepared using nanocomposite plating technology. Uniformly dispersed nano-ZrB2 particles significantly enhanced the hardness and wear resistance of the coating. Upon testing, the hardness of the coating exceeded 700 HV, with a friction coefficient below 0.2, which was superior to those of pure NiCo or other nanocomposite NiCo coatings reported previously. Microscopic analysis revealed that the addition of dispersants and ultrasonic vibration treatment had facilitated the homogeneous distribution of nano-ZrB2 within the matrix, thereby promoting the formation of numerous nano-twins. Due to dispersion strengthening, fine grain strengthening, and twinning strengthening, the wear behavior of the coating changed from fatigue wear to abrasive wear, and the wear volume was significantly reduced by 82%. The above findings could potentially extend the service life of the coating, reduce the cost of steel loss per ton, and have broad application prospects in other surface protection fields. [ABSTRACT FROM AUTHOR]

Abstract To investigate the effect of the filter device on the cleanliness of molten steel and the flow field distribution within the tundish. The tundish filters were designed into five groups of pores with 20°, 25°, 30°, 35° and 40° elevation angles, and the flow field distribution and impurity removal rate of molten steel were calculated by Discrete Phase Model (DPM). The results showed that the removal rate of impurity in the molten steel could be significantly improved by using the tundish filter with elevation angle. When the elevation angle of the filter was 40°, the impurity removal rate reached 74.05%, and the flow field distribution would be more stable. The presence of the tundish filter caused the higher flow density of the molten steel before the filter inlet to decrease and become steadier after the filter, thereby enhancing the contact rate between impurities in the molten steel and the covering agent, ultimately achieving the highest impurity removal rate.

The heat transfer model for steel solidification in Al2O3 crucial and permanent mold by finite element method was developed and validated by temperature measurement. The multi-gradient operation was novelly designed, and the tailored cooling rate in range of 0.1–10 °C/s was obtained at the target location. The simulation aided experiment with the large-sized samples was carried out, and the local cooling rate was verified by secondary dendrite arm spacing. The size of austenite grain decreases slightly as cooling rate increases from 0.15 °C/s to 0.31 °C/s, and then increases dramatically in the range of 0.31–0.48 °C/s, finally decreases with cooling rate increasing further to 9.76 °C/s. The relationship between austenite grain size and cooling rate was logarithmically regressed in the range of 0.48–9.76 °C/s, in which the kinetic equations on basis of cooling experiment and continuously cast slab can also work. However, the grain size decrease in 0.15–0.31 °C/s and then increase in 0.31–0.48 °C/s cannot be described. Based on the mechanism of peritectic solidification, the austenite grain growth is mainly controlled by diffusion at a low cooling rate smaller than 0.31 °C/s, and the final grain size is less than 1.0 mm. At a medium cooling rate between 0.48 and 3.60 °C/s, austenite grain growth is accelerated by the energy stored during massive type peritectic transformation previously, and the grain size is between 1.7 and 2.9 mm. At high cooling rate larger than 9.76 °C/s, austenite grains grow to about 0.9 mm in columnar shape. The time for grain growth is not adequate, although addition energy storage by massive transformation can also occur. The critical cooling rate for the onset of massive type peritectic transformation in the large-sized sample is between 0.31 and 0.48 °C/s. The growth velocity in the isothermal experiment is much smaller than that in continuous cooling process, confirming that the austenite grain evolution is significantly affected by previous peritectic solidification.

The entrapment of argon bubbles and non-metallic inclusions under combined applications of electromagnetic braking (EMBr) and electromagnetic stirring (EMS) is receiving increasing attention in slab continuous casting. A Eulerian-Lagrangian model, incorporating Archimedes electromagnetic force, was established to study the entrapment behavior of particles under multi-mode electromagnetic fields. Results showed that the novel EMBr device could enhance the mixing of liquid steel around the nozzle and significantly suppress inclusion entrapment. The optimal magnetic induction intensity ranged from 0.218 T to 0.272 T based on the number of entrapped particles beneath the slab surface. Furthermore, employing appropriate drag force coefficients and considering the Archimedes electromagnetic force were crucial for predicting the quantity and size of entrapment particles. Particles from the nozzle jet experienced a downward electromagnetic force induced by EMBr. EMS tended to drag particles toward the solidified shell, with a more pronounced effect on large-sized particles. More particles were entrapped by the solidified shell in numerical results. Further research should account for Archimedes electromagnetic force in quantitative examination of inclusion entrapment.

This work formulates and investigates a steel grade design problem (SGDP) arising from a production process of steelmaking continuous casting. For the first time, we consider uncertain yield and demand in SGDP and construct a two-stage robust optimisation model accordingly. Then, we propose an enhanced column-and-constraint generation algorithm to obtain high-quality solutions. By exploiting the problem characteristics, we first use a Lagrangian relaxation method to decompose SGDP into multiple subproblems and then apply a standard column-and-constraint generation algorithm to solve the latter. At last, we test the proposed algorithm by extensive instances constructed based on actual production rules of a steelmaking shop. Numerical results show that it can effectively solve large-scale SGDPs. The obtained plan is better than those obtained by a commonly-used and standard column-and-constraint generation algorithm. [ABSTRACT FROM AUTHOR]

The present paper deals with the resolution on cloud architecture of synchronous and asynchronous iterative parallel algorithms of stationary or evolution variational inequations formulated by a multivalued model. The performances of synchronous and asynchronous iterative parallel methods are compared with previous ones obtained on cluster or when grid architecture is used. Thanks to the properties of the algebraic systems resulting from problem discretization we are able to analyze the behavior of the iterative algorithm in particular the convergence and the speed of convergence. The implementation of the studied methods on cloud architecture is described. Then we present various applications in particular the solidification of steel in continuous casting, the cavity pressure calculation described by a problem subject to unilateral constraints and finally a financial problem modeled by American option pricing. • Implementation of parallel synchronous and asynchronous algorithms on cloud computing for multivalued problems is presented. • Three distinct applications are presented and solved by the studied method. • Analysis of parallel methods applied to the target problems is recalled. • Implementation of algorithms on cloud architecture is described. • Behavior of both numerical simulation on cloud is compared with cluster and grid simulation. [ABSTRACT FROM AUTHOR]

Stir casting processes are utilized primarily to manufacture metal-based materials with random and dispersed reinforcements, thereby enhancing the mechanical properties of alloys. However, continuous network reinforcements are pivotal for high thermal conductivity metal-based materials. To construct the continuous network reinforcements, four stir casting processes on the microstructure and thermal conductivity of the GF (graphite flake)/CF (carbon fiber) Mg (magnesium)-based materials were investigated with the glycerol–water model. The effects of diverse stir casting processes on the construction of the GF/CF continuous network structures followed this order: pre-mixed and laid powder stir casting > semi pre-laid powder stir casting > pre-laid powder stir casting > common stir casting, which is consistent with the order of thermal conductivity. The optimal thermal conductivity of the GF/CF Mg-based materials fabricated by pre-mixed and laid powder stir casting reached 187 W/(m K) with a competitive density of 1.82 g/cm3. The flow and solidification behaviors of the GF/CF were scrutinized for the construction mechanism of the continuous network structure in pre-mixed and laid powder stir casting. The pre-bridging and the disparity in rotational speeds of the GF/CF facilitated the construction of the continuous network structure. The high thermal conductivity GF/CF were readily engulfed by the solid–liquid interface without particle redistribution, which ensured the preservation of the continuous network structure. This research provides valuable insights for manufacturing next-generation high thermal conductivity Mg-based materials utilizing advanced stir casting processes. [ABSTRACT FROM AUTHOR]

Due to the growing interest in lightweight constructions, the continuous casting of nonferrous metals is continuously developing as a result of the cost-effectiveness of this process, which combines several stages of sheet production. Unfortunately, because of the characteristics of the process, the parameters in the roll gap, such as, for example, pressure and temperature, are unknown, significantly affects the understanding of the phenomena occurring in the material during rolling. Therefore, at IMF Freiberg, a sensor consisting of a piezo sensor and two thermocouples measuring the temperature at two different heights was mounted on the surface of the roll, making it possible to control the process parameters live during the TRC trial. The measurements were further supported by a digital twin in the form of a layer model, combining a viscous and solid region for each layer in a single tool. The computations in this tool are performed offline and the computation time is in the order of seconds, thus much less than that of the finite element method. Because the layer model measures the temperature of the magnesium strip, FEM simulations were used to validate measurements from thermocouples. Experimental results have been obtained that allow for a direct correlation between the development of the pressure and temperature and the length of the fully solidified LD part in the roll gap zone, which correlates directly with the effective total equivalent strain. Using the sensor and layer model, it is possible to train a digital twin that can be used for online estimation of the final strip properties obtained in the TRC process. [ABSTRACT FROM AUTHOR]

Lotus-type porous copper was fabricated using a continuous casting method in pressurized hydrogen and nitrogen gas atmospheres. This study evaluates the effects of process parameters, such as the hydrogen ratio, total pressure, and transference velocity, on the resulting pore structure. A continuous casting process was developed to facilitate the mass production of lotus-type porous copper. To achieve the desired porosity and pore diameter for large-scale manufacturing, a systematic evaluation of the influence of each process parameter was conducted. Lotus-type porous copper was produced within a hydrogen ratio range of 25–50%, a transference velocity range of 30–90 mm∙min−1, and a total pressure range of 0.2–0.4 MPa. As a result, the porosity ranged from 36% to 55% and the pore size varied from 300 to 1500 µm, demonstrating a wide range of porosities and pore sizes. Through process optimization, it is possible to control the porosity and pore size. The hydrogen ratio and total pressure were found to primarily affect porosity, whereas the hydrogen ratio, transference velocity, and total pressure significantly influenced pore diameter. When considering these parameters together, porosity was most influenced by the hydrogen ratio, whereas the total pressure and transference velocity had a greater influence on pore diameter. Reducing the hydrogen ratio and increasing the transference velocity and total pressure reduced the pore diameter and porosity. This optimization of the continuous casting process enables the control of porosity and pore diameter, facilitating the production of lotus-type porous copper with the desired pore structures. [ABSTRACT FROM AUTHOR]

In modern high-performance metallurgical equipment, improving energy efficiency is possible by optimally coordinating individual operations and developing approaches and algorithms for multiparameter optimization and management of the general technological process. As part of such a concept, the presented research is dedicated to developing a system for technological and thermal integration of flat steel products' production processes, allowing hot block charging and reducing energy consumption in the reheating furnaces. The presented system includes dynamic synchronization of the processes of continuous casting of steel blocks, transportation to the rolling shops, dwell, and pre-deformation heating. It combines the results of the work of three numerically implemented mathematical models: (i) describing the cooling and solidification of metal in continuous casting; (ii) determining the temperature distribution in each of the hot blocks during transport operations; (iii) determining the optimal regimes in reheating furnaces. The main goal is optimal synchronization of the work of the individual production operations and maximum use of the heat of the hot-charged blocks. The obtained results allowed the evaluation of different scenarios for implementing the process and making decisions about storing the blocks before loading them into the heating furnaces. [ABSTRACT FROM AUTHOR]

This paper demonstrates the feasibility of producing thin-thin slabs from a wide range of aluminum alloys using the twin-roll casting method. In the course of the research, the design and technological solutions of the currently known methods of continuous casting and rolling of sheet metal products were analyzed. In a laboratory setup for strip metal casting, the physical and technological parameters (such as temperature, casting speed, and heat removal rate) were tested to ensure a stable process for the production of thin-thin slabs (1–5 mm) from the aluminum alloys under study. For the first time in the field of metallurgy, the improvement of twin-roll casting technology allowed the cast thin slabs from wide-range aluminum alloys, specifically EN2024 (D16) (≥ 130 °C) and EN7075 (B95) (≥ 160 °C), to be produced. In the initial phase of the research, the impact of the heat removal rate from the solidifying metal on the primary structure of the cast blank was investigated. It is demonstrated that, irrespective of the cooling rate, the α‑phase serves as the basic structure that determines the mechanical characteristics of the metal in cast workpieces for all the studied aluminum alloys. It was demonstrated that as the cooling rate increases to a level characteristic of twin-roll casting, the α‑phase in cast slabs exhibits a more uniform fine-grained structure. In this case, the small inclusions of dispersed intermetallic and eutectic phases present in the structure of cast slabs are evenly distributed across their cross-sections. As is known, there is a hereditary phenomenon between the primary structure of cast slabs and the quality of the final metal product. This relationship was confirmed by the improved strength characteristics of strips obtained by rolling experimental slabs. [ABSTRACT FROM AUTHOR]

Based on a physical water model with a scaling factor of 0.5 and a coupled flow–heat transfer–solidification numerical model, this study investigates the influence of the submerged entry nozzle (SEN) depth on the mold surface behavior, slag entrapment, internal flow field, temperature distribution, and initial solidification behavior in slab casting. The results indicate that when the SEN depth is too shallow (80 mm), the slag layer on the narrow face is thin, leading to slag entrapment. Within a certain range of SEN depths (less than 170 mm), increasing the SEN depth reduces the impact on the mold walls, shortening the "plateau period" of stagnated growth on the narrow face shell. This allows the upper recirculation flow to develop more fully, resulting in an increase in the surface flow velocity and an expansion in the high-temperature region near the meniscus, which promotes uniform slag melting but also heightens the risk of slag entrainment due to shear stress at the liquid surface (with 110 mm being the most stable condition). As the SEN depth continues to increase, the surface flow velocity gradually decreases, and the maximum fluctuation in the liquid surface diminishes, while the full development of the upper recirculation zone leads to a higher and more uniform meniscus temperature. This suggests that in practical production, it is advisable to avoid this critical SEN depth. Instead, the immersion depth should be controlled at a slightly shallower position (around 110 mm) or a deeper position (around 190 mm). [ABSTRACT FROM AUTHOR]

Copyright of Metal Working (1674-165X) is the property of Metal Working Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)