https://journal.issiran.com/ International Journal of Iron & Steel Society of Iran en daily 1 Thu, 22 May 2025 00:00:00 +0330 Thu, 22 May 2025 00:00:00 +0330 https://journal.issiran.com/article_725273.html Continuous casting is a vital and indispensable process in the modern steel industry, enabling the efficient production of high-quality steel products on a large scale. However, significant challenges such as the clogging of submerged entry nozzles (SENs) adversely and critically impact the process. SEN clogging, caused by the deposition of non-metallic inclusions (NMIs) or solidified steel, alters fluid flow, heat transfer mechanisms, and the overall quality of the final product. Recent advancements in computational fluid dynamics (CFD) modeling and sophisticated experimental methods have enhanced the understanding of clogging dynamics significantly. This study examines the effects of clogging-induced changes, specifically variations in jet angle Continuous casting is a vital and indispensable process in the modern steel industry, enabling efficient and large-scale production of high-quality steel. Serious challenges such as the clogging of submerged entry nozzles (SENs), however, negatively affect the process. SEN clogging, caused by the deposition of non-metallic inclusions (NMIs) or solidified steel, alters fluid flow, heat transfer mechanisms, and the overall quality of the final product. Recent advancements in computational fluid dynamics (CFD) and sophisticated experimental methods have significantly deepened our understanding on clogging dynamics. This study examines the effects of clogging-induced changes, specifically variations in jet angles, on flow patterns, vortex formation, and effective heat transfer during continuous casting. Numerical simulations based on Navier-Stokes equations and k-ε turbulence model reveal the drastic influence of jet angles on rotational flow, temperature distribution patterns, and solidification dynamics. Findings conclusively showed that a 0-degree jet angle results in stronger surface fluctuations and thicker solid shells compared to the 15-degree angle, thus improving the product quality and overall stability. s, on flow patterns, vortex formation, and effective heat transfer during continuous casting. Numerical simulations utilizing Navier-Stokes equations and the k-ε turbulence model reveal that jet angles significantly influence rotational flow, temperature distribution patterns, and solidification dynamics. Findings conclusively show that a 0-degree jet angle results in stronger surface fluctuations and thicker solid shells compared to a 15-degree angle, thus impacting product quality and overall stability. https://journal.issiran.com/article_727447.html  Ductile cast irons exhibit excellent wear resistance in frictional applications, primarily due to the inherent lubricating effect of their graphite content. In addition to graphite morphology, the matrix microstructure plays a critical role in governing wear behavior. This study evaluates the influence of various matrix structures on the dry sliding wear performance of spheroidal graphite cast iron. The specimens were produced using the in-mold spheroidizing method and cast into sand molds. To obtain different matrix types, the samples underwent a series of heat treatments, including normalizing, quenching, and austempering at 275 °C, 325 °C, and 375 °C. Microstructural characterization was carried out using optical microscopy and image analysis software. Brinell hardness testing was employed to assess mechanical properties. Dry sliding wear resistance was evaluated using a pin-on-disk tribometer, and the coefficient of friction was monitored throughout the tests. Worn surfaces and associated wear mechanisms were analyzed via scanning electron microscopy (SEM). The results indicated that the quenched sample exhibited the highest wear resistance, with a specific wear rate of 1.9 × 10⁻⁶ mm³/N.m. The normalized and austempered samples (at descending order of 275 °C, 325 °C, and 375 °C), followed by the as-cast condition, showed progressively lower performance. The dominant wear mechanism in the quenched sample was identified as a combination of oxidative wear and adhesive wear  https://journal.issiran.com/article_728330.html  In this study, the effect of carbon content, the primary element in the chemical composition of carbon steel grades, on the solidification of steel slabs is investigated using a numerical simulation approach. Three commercial carbon steel grades with varying carbon contents are selected. Technological and operational conditions, such as slab geometry, water flow rates of spray nozzles in the secondary cooling zone, mold features, casting speed, and the temperature of spray cooling water in the secondary cooling zone, are held constant and based on a real industrial continuous slab casting machine. The thermophysical properties of each steel grade are computed based on the calculation of phase diagrams (CALPHAD). The numerical simulation of the process is then conducted by solving the heat transfer equation (coupled with the CALPHAD-based thermophysical properties) based on computational fluid dynamics (CFD) simulated in the MATLAB environment. Parameters such as metallurgical length and solid shell thickness profiles are calculated and compared over time for various steel grades. In addition, the factor K in the famous square root function for solid shell thickness (as a function of time) is determined and analyzed for each grade. This study demonstrates that increasing the carbon content decreases the metallurgical length. As carbon content decreases, the thickness factor K increases in carbon steel grades.  https://journal.issiran.com/article_728478.html  Waspaloy is a wrought Ni-based superalloy that is widely used in high-temperature structural applications requiring strength retention and performance at elevated temperatures, such as gas turbine engines and aerospace components. This study primarily focuses on the exploration of the impact of heat treatment on the microstructure and high-temperature mechanical properties of the Waspaloy superalloy. The experiment involved processing the alloy in both hot-rolled and cold-rolled conditions, followed by stabilization at 845 ℃ and aging at various temperatures: 730 ℃, 760 ℃ and 800 ℃. Subsequent mechanical property evaluations were conducted using hardness, hot tensile, and stress rupture tests. To examine the microstructural changes, we employed optical and scanning electron microscopy. Our findings revealed that the cold-rolled specimen, aged at 730 ℃, exhibited the highest hardness, 581 Vickers. Moreover, our hot tensile test results showed a maximum yield strength of 1340 MPa and an ultimate tensile strength of 1404 MPa for the cold-rolled specimen after aging at 730 ℃. The stress rupture test revealed a rupture time of 46 hours for the cold-rolled specimens and 36 hours for the hot-rolled specimens, attributable to the increased size and volume fraction of γ' precipitates in the cold-rolled alloy.  https://journal.issiran.com/article_728676.html  A heat treatment cycle involving step-quenching followed by intercritical annealing (IA) at 740°C, 770°C and 800°C for times between 2-12 min was utilized to produce dual-phase (DP) steels. The microstructural analysis revealed that the martensite islands formed during step-quenching were refined significantly after IA. The final DP steels contained ferrite grains of two sizes distribution: coarse grains ranging from 10 to 25 µm and ultrafine grains smaller than 2 µm. The martensite islands displayed two morphologies: fine and fibrous martensite in samples annealed at 740°C and 770°C and equiaxed martensite islands in all samples. Continuous yielding behavior was observed in all samples except those annealed at 740°C for 2- and 4-min. IA at all temperatures led to a decrease in yield stress and ultimate tensile strength, with enhancements in uniform elongation and total elongation only observed after IA at 740°C and 770°C. The sample annealed at 770°C for 12 min exhibited the best combination of tensile properties for auto body applications. The samples displayed a three-stage work-hardening behavior based on the modified Crussard–Jaoul analysis, however the third stage was absent in samples annealed at 740°C for 7 and 12 min due to the high carbon content of the martensite.  https://journal.issiran.com/article_729026.html  The introduction of high-entropy material has provided the possibility of efficiently producing low-cost advanced materials with several unique properties suitable for industries. High-entropy materials have gained significant interest because they can be tailored to have functional properties. Among the highentropy material are the high entropy oxides. The objective of this study was to synthesize (Mg0.2Ti0.2Zn0.2Cu0.2Fe0.2)3O4 high entropy oxides (HEO) using different iron sources of Fe 2O3, Fe3O4, and Fe2O3/Fe3O4 mixture and to study their structure and magnetic properties. Solid state synthesis method was used to obtain (Mg0.2Ti0.2Zn0.2Cu0.2Fe0.2)3O4 using low-cost raw materials and different iron sources. The XRD diffraction patterns along with the Rietveld analysis indicated that for the three iron source(s), a pure single-phase Fd3̅m spinel structure was obtained after the heat treatment at 1000 ℃ for 24 hours. The SEM images and elemental MAP analysis indicated that the powders were agglomerated with semispherical morphology and the constituent elements were uniformly distributed. Magnetic test results obtained from the VSM test revealed that the magnetic properties are severely influenced by the iron source used for the synthesis of the (Mg0.2Ti0.2Zn0.2Cu0.2Fe0.2)3O4 HEO samples. The HEO samples obtained using the Fe 3O4 sample had better magnetic properties (Ms= 13.93, Mr= 4.39, and Hc=350) compared to the other two samples.  https://journal.issiran.com/article_732067.html In this research, simple modeling and simulation were used, and the dimensions and characteristics of the mushy zone in medium carbon steel during continuous casting were investigated. For this purpose, a numerical solution of the heat transfer equation as well as analytical microsegregation equations were used, and the following items were determined as mushy zone characteristics: mushy zone width, mushy core, mushy zone area, overall and local solidification time, local cooling rate, and brittle region characteristics. The width of the mushy zone increases up to a certain point along the length of the billet and then decreases to zero. The length of the billet over which the width of the mushy zone decreases from a maximum value to zero is called the mushy core in which the temperature gradient increases at an increasing rate. As the distance from the meniscus rises, the local solidification time in the mushy zone increases linearly, and the cooling rate of this zone decreases rapidly. Overall and local solidification rate decreases throughout the billet length, but the local solidification rate experiences a sudden increase at the beginning of the mushy core. The behavior of brittle zone width is similar to that of the mushy zone, but the slope of its decrease is much greater.