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The fluid flow of liquid steel in a wide slab mold (1880 × 230 mm) influenced by two different submerged entry nozzle (SEN) designs (bifurcated nozzles with rectangular, SEN-R, vs square, SEN-S, ports) and immersion depths of 115 and 185 mm was studied using a 1:1 scale water model. To analyze the fluid dynamics, particle image velocimetry and video recording techniques were used. The fluid-flow dynamics indicate that the discharging jets using either SEN design suffer strong wandering and raveling effects that enhance turbulence in the meniscus region. The preceding results show the existence of velocity spikes (defined as velocities with magnitudes that exceed the standard deviation of the average velocity) in the submeniscus region. Using the SEN-R ports yields more velocity spikes per minute with larger magnitudes than using the SEN-S, which could be the main cause of the detrimental quality of steel. The capability of slag entrainment by the flow developed by a nozzle was the criterion employed to evaluate quantitatively the merits of one nozzle over the other. This criterion is based on the capillary number, which gives the ratio between viscous-inertial and surface forces at the metal–slag interface.

Effective thermal management is essential in welding processes to maintain structural integrity and material quality, especially in high-precision industrial applications. This study examines the thermal behavior of an AISI 1080 steel plate containing 100 blind holes filled using robotic electric arc welding. Temperature measurements, recorded with eight strategically positioned thermocouples, monitored the thermal evolution throughout the robotic welding process. The experimental results validated a computational heat transfer model developed with ANSYS Fluent software to simulate and predict temperature distribution achieving a mean absolute percentage error (MAPE) below 4.53%. A feedforward neural network was trained with simulation-generated data to optimize welding sequences. The optimization focuses on minimizing the area under the thermal history curves, reducing temperature gradients, and mitigating overheating risks. Integrating CFD simulations and neural networks introduces a hybrid methodology combining precise numerical modeling with advanced predictive capabilities. The hybrid CFD-FNN results reached a determination coefficient (R2) of 0.93 and an MAPE of 3.5% highlighting the potential of this approach to predict the thermal behavior in multipoint welding processes. This model generated optimized welding trajectories improving the uniformity of the temperature field, reducing thermal gradients and minimizing temperature peaks, thus aiding in preventing overheating. This framework represents a significant advancement in welding technologies, demonstrating the effective application of deep learning techniques in optimizing complex industrial processes.

The characterization of the fluid flow of liquid steel in a slab mold, using two nozzle designs under unclogged and clogged conditions, is performed using physical and mathematical simulations. Nozzle A, with an expanding and contracting geometry, yields larger sub-meniscus experimental velocities than nozzle B, with internal flow deflectors. The numerical predictions indicate quick time-changing velocity profiles in the submeniscus region between the mold’s narrow face and the nozzles. The flow deflectors in nozzle B have two effects; the high dissipation rate of kinetic energy in the upper-half length induces lower velocities in the ports than nozzle A. The neutralization of the biased flow caused by the sliding gate allows a balanced fluid through the ports. According to the results, nozzle A yields velocity profiles in the sub-meniscus region with larger standard deviations than nozzle B, leading to an unstable bath surface. The clogged nozzles produced biased-asymmetrical flow patterns in the mold, finding approximated matchings between numerical predictions and experimental measurements. The internal protrusions of the deposits lead to covariance losses of the bath surface wave heights. The use of internal deflectors helped to decrease the amount of clog material in nozzle B.

Backup rolls are the main tool in a four-high rolling mill; the rolling forces applied in load cells promote the fatigue of the material due to mechanical contact between backup rolls and work rolls. This work investigated the causes of recurrent failures in backup rolls, with cracking always initiated on the surface of the roll body and finishing in the main radius between neck and roll body. Aiming to find the causes of failure, visual inspection and morphology of the fracture were performed, complemented with mechanical tests of hardness on the stress concentration area, in addition to validating the results by applying the finite element method, using ANSYS Mechanical Static Structural Software. It was concluded that the fatigue crack initiated on the surface of BUR due to work hardening continued growing up over the fatigued material, creating beach marks, and finally, a fracture occurred in the main radius of BUR due to stress concentration. The work hardening is the main cause of spalling on BURs and other mechanical components exposed to mechanical contact.

The complete rolling schedule (25 passes) of steel beams in a mill was simulated to predict the final beam length, geometry of the cross-section, effective stress, effective plastic strain and rolling power for two cases; the first case corresponds to the hot rolling process assuming a constant temperature of 1200 ∘C. The simulation of the second case considered the real beam temperature at each pass to compare the results with in-plant measurements and validate the numerical model. Then, the results of both cases were compared to determine the critical passes of the process with high peaks of required power, coinciding with the reports at the mill. These critical passes share the same conditions, high percentage of reduction in cross-sectional area and low beam temperature. Additionally, a potential reduction of passes in the process was proposed identifying passes with low required power, minimal reduction in area of cross-section and essentially unchanged geometry. Therefore, it is reasonable to state that using the present research methodology, it is possible to have a better control of the process allowing innovation in the production of profiles with more complex geometries and new materials.

One of the most common problems in flat rolling process is the control of flatness and distribution of pressure between work rolls and strips, this problem is critical considering the requirements of flatness in dimensional quality of strip. To try to control the dimensional flatness and shape of the strip, studies have been conducted for each mill individually, considering roller deflection, wear, thermal crowns, etc. However, the problem persists. This study presents a numerical and experimental investigation of the influence of roll crown geometry on the flatness of hot rolling AISI 1015 steel. Three configurations were analyzed: negative crown (–0.1 mm), flat rolls (0 mm), and positive crown (+ 0.1 mm), using finite element simulations validated with industrial data from a Steckel mill. The simulation model was developed in Simufact Forming 2022 under realistic thermal and mechanical boundary conditions. The results indicate that the positive crown configuration provides the most uniform thickness distribution (± 0.05 mm) and stable deformation behavior, while the negative crown leads to edge waviness and dimensional instability. Statistical validation using a paired t test yielded a mean thickness difference of 0.015 mm with a p value < 0.001, confirming strong agreement between the simulated and experimental results. Although rolling forces were overestimated by approximately 1.056 times due to model simplifications, the overall deformation and force trends were consistent, demonstrating the model’s suitability for industrial hot rolling process optimization.

The design of the ports of a casting nozzle has profound effects on the fluid flow patterns in slab molds. The influence of these outlets have also considerable effects on the turbulent flow and turbulence variables inside the nozzle itself. To understand the effects of nozzle design, three approaches were employed: a theoretical analysis based on the turbulent viscosity hypothesis, dimensional analysis (both analyses aided by computer fluid dynamics), and experiments using particle image velocimetry. The first approach yields a linear relation between calculated magnitudes of scalar fields of ε (dissipation rate of kinetic energy) and k 2 (square of the turbulent kinetic energy), which is derived from the wall and the logarithmic-wall laws in the boundary layers. The smaller the slope of this linear relation is, the better the performance of a given nozzle is for maintaining the stability of the melt–flux interface. The second approach yields also a linear relation between flow rate of liquid metal and the cubic root of the dissipation rate of kinetic energy. In this case, the larger the slope of the linear relation is, the better the performance of a given nozzle is for maintaining the stability of the melt–flux interface. Finally, PIV measurements in a mold water model, together with equations for estimation of critical melt velocities for slag entrainment, were used to quantify the effects of nozzle design on the dynamics of the metal–slag interface. The three approaches agree in the characterization of turbulent flows in continuous casting molds using different nozzles.

The optimization of submerged entry nozzle (SEN) designs plays a pivotal role in achieving stable flow conditions and high-quality steel production during continuous casting. This study presents a comparative analysis of two SEN geometries under identical operational parameters using a combined approach of numerical simulation and physical modeling. A full-scale water model and a validated CFD framework based on the realizable k-ε and VOF models were employed to evaluate velocity distribution, turbulence intensity, free surface behavior, and flow symmetry. Results reveal that the SEN-2 design enhances flow stability near the meniscus region, promotes a consistent double-roll flow pattern (DRF), and reduces surface oscillations and sub-meniscus velocities, thereby minimizing the risk of mold flux entrapment. The proposed dimensionless KE number effectively quantifies the energy dissipation behavior of both designs, highlighting SEN-2’s superior hydraulic performance. This integrated methodology offers a robust evaluation framework for future nozzle development aimed at improving product quality without compromising productivity.

The effects of nozzle design on dispersed, two-phase flows of the steel-argon system in a slab mold are studied using a water-air model with particle image velocimetry and ultrasound probe velocimetry techniques. Three nozzle designs were tested with the same bore size and different port geometries, including square (S), special bottom design with square ports (U), and circular (C). The meniscus velocities of the liquid increase two- or threefold in two-phase flows regarding one-phase flows using low flow rates of the gas phase. This effect is due to the dragging effects on bubbles by the liquid jets forming two-way coupled flows. Liquid velocities (primary phase) along the narrow face of the mold also are higher for two-phase flows. Flows using nozzle U are less dependent on the effects of the secondary phase (air). The smallest bubble sizes are obtained using nozzle U, which confirms that bubble breakup is dependent on the strain rates of the fluid and dissipation of kinetic energy in the nozzle bottom and port edges. Through dimensionless analysis, it was found that the bubble sizes are inversely proportional to the dissipation rate of the turbulent kinetic energy, ε0.4. A simple expression involving ε, surface tension, and density of metal is derived to scale up bubble sizes in water to bubble sizes in steel with different degrees of deoxidation. The validity of water-air models to study steel-argon flows is discussed. Prior works related with experiments to model argon bubbling in steel slab molds under nonwetting conditions are critically reviewed.

The turbulent phenomena occurring in the thin slab mold affect the final product quality. Therefore, it is essential to carry out studies to understand and control their occurrence. Current research aims to study the electromagnetic brake (EMBr) effects on the flow patterns in a funnel thin slab mold. The objective is to prevent the detrimental phenomenon known as dynamic distortions (DD) of the flow, applying the EMBr in the typical horizontal position (H-EMBr) and a new vertical position close to the narrow faces (V-EMBr). The fluid dynamics are simulated using the Reynolds stress model (RSM), the Volume of Fluid (VOF) model and the Maxwell equations in their magnetohydrodynamics (MHD) simplification. The results show that the H-EMBr effectively counteracts the DD phenomenon by reducing the submerged entry nozzle (SEN) ports' mass flow rate differences. The EMBr reduces the highest meniscus fluctuations from −10 to ±3 mm with a field intensity of 0.1T and almost 0 mm for higher field intensities. In contrast, the V-EMBr configuration does not reduce or control at all the DD phenomenon, even though eliminating the upper roll flows does not diminish the meniscus fluctuation amplitudes and induces new small roll flows close to the SEN's wall.