Nozzle clogging is a persistent problem in continuous casting, adversely affecting casting stability and steel cleanliness. It disturbs molten steel flow in the mold, hinders inclusion flotation, and deteriorates slab quality. This review summarizes the morphology and layered structure of clog deposits in different steel grades and discusses the main clogging mechanisms, including non-metallic inclusion deposition, interfacial reactions between molten steel and nozzle refractories, temperature-induced inclusion precipitation, and local steel solidification. Numerical simulation studies are also reviewed for their application in describing clogging evolution. The main influencing factors and control strategies are reviewed in terms of molten steel composition, nozzle refractory materials and structures, casting parameters, and external electric field treatment. Electric field treatment shows potential for suppressing inclusion deposition, although its operating parameters and industrial application require further investigation.
As a critical unit in metallurgical processing, the tundish plays a vital role in ensuring smooth continuous casting operation, facilitating the flotation and removal of non-metallic inclusions, and enhancing the cleanliness and homogeneity of molten steel. This study addresses the key issues of flow-field non-uniformity, significant inter-strand response time disparity, poor inclusion removal efficiency, and notable temperature gradient in a large-spacing eight-strand continuous casting tundish. A hybrid methodology integrating scaled physical experimentation with high-fidelity numerical simulation was employed to optimize flow dynamics and quantify inclusion transport and removal. Based on the principle of similarity, a 1:3-scale plexiglass physical model was established with U- and V-shaped porous baffles as the core flow control elements, respectively. Multiple combination schemes were designed by varying the diameter, position, inclination angle, and deflection angle of the diversion holes. Residence time distribution curves were experimentally acquired via the stimulus-response method, and quantitative hydraulic metrics, including dead zone volume fraction, plug flow volume fraction, and mixed (dispersive) volume fraction, were rigorously evaluated. Meanwhile, a three-dimensional numerical model was developed using the realizable k-ε turbulence closure and the discrete phase model to resolve the coupled flow, thermal, and particle-tracking phenomena. Flotation behavior of inclusions with sizes ranging from 20 to 100 μm was revealed. Results indicate that the U-shaped baffle configuration consistently outperforms its V-shaped counterpart: the optimal U-shaped scheme achieves a minimum dead zone volume fraction of 18.69% and a maximum mean residence time of 521.56 s. In numerical simulations, the optimized U-shaped baffle scheme CU2 yields a standard deviation of outlet temperature of merely 0.214 K and achieves inclusion removal efficiencies of 46.1% (20 μm) and 62.1% (40 μm), representing substantial improvements over the optimal V-shaped alternative. Furthermore, a newly proposed pentagonal eaved turbulence inhibitor demonstrates well-balanced, comprehensive advantages relative to conventional square and circular designs, exhibiting enhanced thermal field uniformity, stable and consistent inclusion removal across all strand positions, and greater flexibility in retrofit installation within existing tundish geometries. Collectively, these findings provide theoretical guidance for the industrial application of flow control devices in large-spacing eight-strand tundishes.
This study examined the electro-discharge machining (EDM) performance of Ti-6Al-4V alloy utilizing a WC/Cu powder metallurgy electrode using hybrid response surface methodology (RSM) and artificial neural network (ANN) techniques. The effects of peak current ( I p ), pulse-on time ( T on ), pulse-off time ( T off ), and discharge voltage ( V g ) on material removal rate (MRR) and surface roughness (Ra) were analyzed using Box–Behnken design. Regression models developed using RSM demonstrated excellent prediction accuracy with the coefficient of determination ( R 2 ) values of 99.89% for MRR and 99.88% for Ra. ANOVA results confirmed that I p and T on were the most significant parameters influencing machining performance. MRR increased from 13.5 to 30 mm 3 /min as I p increased from 5 to 15 A, while Ra increased from 2.4 to 4.3 μm owing to the increased spark energy and crater formation. The ANN model with a 4-10-2 architecture demonstrated outstanding prediction performance with an overall regression coefficient ( R ) of 0.99054 and a minimal validation mean squared error of 0.36696, confirming strong agreement between predicted and experimental data. Multi-response optimization using the desirability function approach identified optimal machining conditions at I p = 14.0909 A, T on = 54.0404 μs, T off = 15.6566 μs, and V g = 80 V, yielding a predicted MRR of 23.942 mm 3 /min and an Ra value of 3.7608 μm with a composite desirability of 0.9782. SEM and EDS analyses confirmed enhanced surface integrity with shallow craters, fewer microcracks, and Cu and W element deposition on the machined surface. The outcomes demonstrated that the hybrid RSM–ANN technique effectively optimized EDM performance and improved machining characteristics of Ti-6Al-4V alloy using a WC/Cu PM electrode.
High-chromium (>12 wt.%) oxide dispersion-strengthened (ODS) ferritic steels are promising structural materials for advanced fission, fusion and high-temperature energy systems because a body-centred-cubic ferritic matrix combines low swelling susceptibility with thermally stable nanoscale oxides. Their deployment, however, remains constrained by processing-induced morphological and crystallographic anisotropy, difficult tube fabrication and limited industrial-scale qualification. This systematic review critically evaluates the processing-microstructure-property relationships that govern these limitations. Literature was screened across ScienceDirect and the Web of Science Core Collection using ODS-, high-Cr-, anisotropy-, consolidation-, irradiation- and advanced-manufacturing-related search terms, while seminal earlier studies were retained for historical context. Hot extrusion provides >99% relative density and a fine microstructure but commonly generates strong <110> deformation texture and elongated grains; HIP and SPS can produce more equiaxed structures but present different density, texture, scale-up and property trade-offs. Two-step recovery-recrystallization treatments and controlled high-temperature deformation can reduce anisotropy, although repeated processing increases cost, time and dimensional-control requirements. Recent laser-based routes offer near-net-shape capability but introduce new challenges involving oxide dissolution/reprecipitation, porosity, oxygen control and solidification texture. The review further integrates irradiation response, competing nuclear structural materials, commercialization barriers and emerging characterization/digital-design approaches. The resulting synthesis identifies processing windows and research priorities required to translate high-Cr ODS ferritic steels from laboratory-scale optimization toward reproducible component manufacture and qualification.
The high-temperature annealing treatment of grain-oriented silicon steel is a complex process, and the heating rate significantly influences the formation of the strong Goss texture. This study investigates the impact of the heating rate on the secondary recrystallization behavior of low-temperature grain-oriented silicon steel during the high-temperature annealing process. The microstructure, microtexture, and precipitated phases of the samples were characterized using an optical microscope, field emission scanning electron microscopy (SEM) combined with electron backscatter diffraction (EBSD), and energy dispersive spectroscopy (EDS). The magnetic properties of the finished plates were evaluated using a TD8735 single-chip permeameter designed for silicon steel measurement. The results demonstrate that at a heating rate of 15 °C/h, the onset temperature of secondary recrystallization is 1080 °C and the completion temperature is 1090 °C; at a heating rate of 10 °C/h, the onset temperature is 1070 °C and the completion temperature remains at 1090 °C. An increase in the heating rate delays the onset of secondary recrystallization, and narrows the temperature range for secondary recrystallization. Under both heating rates, the test steel exhibits superior performance at a heating rate of 10 °C/h. The core loss P 1.7/50 reaches 1.02 W/kg, and the magnetic induction intensity B 800 reaches 1.88 T, which meets the magnetic induction index requirements for high magnetic induction grain-oriented silicon steel. The texture evolution trends under both heating rates are similar. Observations of the texture changes at a heating rate of 10 °C/h reveal that textures such as {411}<148> and {111}<112> gradually transform into the Goss texture as the annealing temperature increases. The Zener factor of inhibitor particles decreases with increasing annealing temperature under different heating rates. When the annealing temperature reaches 1070 °C, the Zener factor at a heating rate of 10 °C/h is lower than that at 15 °C/h, indicating that secondary recrystallization commences earlier at a heating rate of 10 °C/h.
