• Issue

    steel research international: Volume 95, Issue 4

    April 2024

Cover Picture

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Cover Picture

  • First Published: 02 April 2024
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Cover image credit to Susanne Schüler, B.Eng.

Masthead

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Masthead

  • First Published: 02 April 2024

Contents

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Contents: steel research int. 4/2024

  • First Published: 02 April 2024

Research Articles

Role of Cerium on the Intricacies of Deformed State and Softening Mechanisms of Low-Carbon Steels

  • First Published: 05 January 2024
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Two Cerium (Ce) added steels designated as low Ce (LCe) (0.03 wt% Ce) and high Ce (HCe) (0.6 wt% Ce) are 60% cold rolled and subcritically annealed at 600 °C, for 2-16 h. During annealing, the influence of Ce, its precipitates (Ce2O3, Ce2O2S, and CeO2), and intermetallics (Ce2Fe17 and Ce2C3) on the softening mechanisms of above mentioned steels have been investigated.

Effects of Calcium Addition on Nonmetallic Inclusions in High-Al Steel

  • First Published: 05 January 2024
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The evolution mechanism of inclusions treated by calcium (Ca) in high-Al steel is investigated. The Al2O3 inclusions are modified to (CaO–Al2O3)–CaS after Ca addition. Ca treatment leads to two types of (CaO–Al2O3)–CaS inclusions. Based on the total calcium content/total oxygen content, a new modification index is given to clarify the formation of CaS inclusion.

High-Temperature Oxidation Behavior of Cr-Si Alloyed Press-Hardened Steel in Comparison with 22MnB5 Steel

  • First Published: 02 January 2024
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Herein, it is revealed that the superior high-temperature oxidation resistance of a novel Cr–Si-alloyed coating-free press-hardened steel (CF–PHS) compared to 22MnB5 at 1000–1150 °C is attributed to the existence of FeCr2O4 and Fe2SiO4. And, the deterioration of oxidation resistance of CF–PHS at 1200 °C owes to the melting of Fe2SiO4.

Deformation Behavior and Texture Evolution of Ferrite and Austenite Phases in Lean Duplex Stainless Steel

  • First Published: 10 January 2024
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A short process of direct cold rolling following solution treatment of the casting billet for preparing lean duplex stainless steel plates is proposed. The effect of cold rolling reduction on the microstructure, texture, and mechanical properties of UNS S32101 is investigated.

Superior Yield Strength and High-Tensile-Toughness Matching of Medium-Mn Steel with Gradient Structure Developed by Cyclic Torsion

  • First Published: 07 January 2024
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A novel multiple-gradient-structured medium-Mn steel is successfully fabricated by cyclic torsion. An outstanding simultaneous improvement in yield strength, ultimate tensile strength, and tensile toughness is achieved in the gradient sample. A persistent transformation-induced plasticity effect and heterogeneous-deformation-induced (HDI) hardening over the entire uniform strain range are conducive to excellent ductility/toughness. The HDI strengthening and dislocation strengthening primarily contribute to the high strength.

Stabilizing Flow of Molten Steel in Mold during Slab Continuous Casting through Electromagnetic Swirling Flow in Nozzle

  • First Published: 07 January 2024
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A novel electromagnetic swirling flow in nozzle (EMSFN) technique is proposed, which utilizes electromagnetic force for stabilizing the flow in nozzle and subsequently controlling the flow in mold during slab continuous casting. The results indicate that with the effect of EMSFN, the flow field and surface velocity on both sides of the nozzle are constantly symmetrical and change uniformly.

Open Access

Influences of Weld Nugget Shape and Material Gradient on the Shear Strength of Resistance Spot-Welded Joints

  • First Published: 12 January 2024
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Total dome failure is a fracture mode of resistance spot-welded joints, where the weld nugget completely separates from one steel sheet along the weld nugget edge. This study looks at the role of weld nugget shape and material gradient in the occurrence of total dome failure by means of finite-element simulations.

Editor's Choice

Simulation of B Segregation at Austenite Grain Boundary in Low Carbon Steel

  • First Published: 13 January 2024
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A finite difference computer model has been constructed for diffusion and segregation of boron (B) in low carbon austenite. The B enrichment occurred almost entirely by the diffusion of interstitial B, and the contribution of B-vacancy complex is unlikely to be significant. The influence of grain size and the interaction with alloying elements were also simulated.

Dynamic Prediction with Statistical Uncertainty Evaluation of Phosphorus Content Based on Functional Relevance Vector Machine

  • First Published: 10 January 2024
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This manuscript proposes a novel method, named the Functional Relevance Vector Machine (FRVM) method, to predict the change of molten steel's phosphorus content as well as its probabilistic confidence interval during the steelmaking process. Experiments indicate that the hit rate of the end-point phosphorus content by the FRVM method is 86.46% when the prediction error is within ±0.005 wt%.

Hot Deformation Behavior and Microstructure Evolution of 2Cr12Ni4Mo3VNbN Steel Used for Last-Stage Large Blades of Steam Turbine

  • First Published: 04 January 2024
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2Cr12Ni4Mo3VNbN steel is a newly developed martensitic stainless steel used for last-stage large blades of steam turbine. Herein, the hot deformation behavior and microstructure evolution of 2Cr12Ni4Mo3VNbN steel are investigated for the first time. Constitutive equations and hot-processing maps of 2Cr12Ni4Mo3VNbN steel are established. Combined processing maps and microstructure evolution, the optimum windows of hot processing are obtained.

Precipitation, Growth, and Aggregation Behavior of Primary Carbides during Continuous Casting of 6Cr13 Slabs

  • First Published: 07 January 2024
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All carbides in 6Cr13 high-carbon martensitic stainless-steel continuous casting slab are polymerized from small particles of carbides with different orientations. The size of the dendritic gap, cooling rate, and spot segregation results in large differences in the distribution, morphology, and size of primary carbides at different locations in the slab.

Evolution of Microstructure and Fe/Fe3C Interface Structure in Cold-Drawn Pearlitic Steel Wires

  • First Published: 04 January 2024
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During the cold drawing process, pearlite lamellae turn to the drawing direction to form ferrite <110> fiber texture; the cementite lamellae are divided into a multilayer structure, and the dissolution of cementite lamellae in some regions results in the lattice expansion of ferrite phase and the occurrence of neck-down regions in the cementite lamellae.

Comparison of Microstructure and Mechanical Properties of a High-Carbon Bainitic Steel Treated by Long-Time Bainitic Austempering and Short-Time Austempering Plus Tempering Processes

  • First Published: 04 January 2024
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Long-time austempering treatment can reduce the volume fraction of brittle martensite. However, the cementite precipitates in the austenite during the long-time austempering process, which decreases the carbon content in retained austenite (RA) and consequently reduces the mechanical stability of RA. In comparison, excellent mechanical properties were obtained in the samples after short-time austempering plus tempering treatment.

Improvement of Microstructure and Mechanical Properties of Hot-Formed Steel with Ce Addition

  • First Published: 07 January 2024
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The mechanism of Ce improves the strength and elongation of hot-formed steel is mainly modified inclusion and microalloying. The modification of nonmetallic inclusions by Ce improves the fracture behavior of hot-formed steel. Meanwhile, lattice expansion caused by solid solution Ce leads to the formation of substructure with high density dislocation and tiny twins, and enhances the strength of martensitic structure.

Acceleration of Spheroidization in Low-Density Ultrafine Pearlitic Steel by κ-Carbide

  • First Published: 13 January 2024
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In this article, by adding 5% mass fraction aluminum to pearlite steel and annealing in different ways to form κ-carbide, it is found that the carbide can significantly refine the lamellae spacing of low-density ultrafine pearlite, and accelerate the spheroidization of low-density ultrafine pearlite during the annealing process.

Investigation on Recrystallization Behavior of Cold-Rolled Silicon Steel in Continuous Heating with Three-Point Bending Testing

  • First Published: 09 January 2024
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A new analysis method based on the Ozawa–Flynn–Wall model is introduced to accurately describe the nonisothermal recrystallization kinetics, showing excellent agreement with the experimental measurements. The experimental results enable direct prediction of the recrystallization fraction during the continuous heating process, providing valuable insights for the design and optimization of continuous annealing processing parameters.

Unlocking the Mechanisms behind Austenite Formation of Cold-Rolled Ferrite–Martensite Dual-Phase Steels: The Role of Ferrite Recrystallization

  • First Published: 18 January 2024
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Austenite formation behavior is investigated for the ferrite–pearlite initial microstructure, considering the influence of ferrite recrystallization and cementite distribution. Austenite transformation kinetics is well predicted by considering the varied nucleation density due to different recrystallization state. The proceeding of recrystallization postpones the austenite transformation kinetics, while getting rid of the interference of heating rate and nucleation location.

Thermomechanical Control of Microstructure and Precipitation in Vanadium Microalloyed Steel: Influence of Finish Rolling and Coiling Temperatures

  • First Published: 04 January 2024
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The article reports the microstructural properties and precipitation behaviors of vanadium microalloyed steel. This steel is treated with a thermal–mechanical-controlled process (TMCP) machine. A total deformation of 87% is obtained. The size and position of precipitated phase in V-microalloyed steel are changed by adjusting finish rolling temperature and coiling temperature in TMCP process.

Effects of Cerium Content on the Nonmetallic Inclusions and Impact Toughness of Transformation-Induced Plasticity Steel

  • First Published: 07 January 2024
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The effects of Ce treatment on inclusion and impact toughness of transformation-induced plasticity (TRIP) steel are investigated. After Ce addition, the inclusions are transferred to Ce-Al-O, Ce2O2S, CeS, and Ce2O3. With addition of 0.0075 wt% Ce, the inclusion obtains a minimum values of number density and average diameter, and the TRIP steel has a better impact toughness. 

YOLOv5s-GC-Based Surface Defect Detection Method of Strip Steel

  • First Published: 07 January 2024
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To balance the speed and accuracy in strip surface defect detection, a novel You Only Look Once v5s-GC method is proposed based on convolutional block attention module, GhostBottleneck, and YOLOv5s. It incorporates residual network mini for preclassification and introduces OTSU and normal distribution enhancement algorithm for image preprocessing. The network achieves an average accuracy of 82.4% with 24% inference speed increase.

Motion Behavior of Ce-Containing Inclusions in 8Cr4Mo4V-Bearing Steel during Vacuum Arc Remelting

  • First Published: 09 January 2024
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The motion behavior of Ce-containing inclusions in vacuum arcremelting is closely related to the inclusion characteristics. The decrease in density and increase in diameter of inclusions make the net effect of buoyancy and gravity increase, and the inclusions are more likely to escape from mushy zone and exhibit a stronger tendency to migrate toward the molten pool's center.

A Comparative Study of Ratcheting Fatigue Behavior of Modified 9Cr–1Mo Steel and Inconel 617 Alloy at Homologous Temperature of 0.42

  • First Published: 18 January 2024
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Ratcheting fatigue refers to the cumulative damage and wear experienced by materials subjected to repeated loading and unloading cycles. This phenomenon is particularly significant in engineering and manufacturing, where components undergo cyclic stress. Over time, the repetitive application of loads can lead to microstructural changes, cracks, and eventual failure. Understanding and mitigating ratcheting fatigue is crucial in designing durable and reliable structures, ensuring long-term performance.

Stress Intensity Range Dependent Slowing Down of Fatigue Crack Growth under Strain-Induced Martensitic Transformation of Film-Like Retained Austenite

  • First Published: 22 January 2024
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Fatigue crack growth rate as well as the slope of the crack growth rate versus ΔK for 0.2%C steel with martensite and 7.5% (blocky + filmy) retained austenite are lower than for martensite. Increasing extent of stain-induced martensitic transformation occurs with increasing Δ K $$ \Delta K$$ . Blocky austenite transforms completely at low Δ K $\Delta K$ , while filmy austenite transforms gradually with increasing Δ K $\Delta K$ till catastrophic fracture.

Open Access

Coupling of Solidification and Heat Transfer Simulations with Interpretable Machine Learning Algorithms to Predict Transverse Cracks in Continuous Casting of Steel

  • First Published: 26 January 2024
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Phenomenological quality criteria extracted from a solidification and microstructure model known as InterDendritic Solidification are utilized to predict transverse cracking in peritectic CMn, low-carbon BTi microalloyed, and peritectic Nb-microalloyed steels during continuous casting with interpretable machine learning models. Balanced accuracies of 92%, 94.6%, and 82.8% indicate good predictive power, and interpretability enables the analyses of transverse cracking.

Effect of Ce Addition on Inclusions and Primary Carbide Network in AISI 440C Bearing Steel

  • First Published: 22 January 2024
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The effect of Ce content on the inclusion and solidification structure of bearing steel AISI 440C is investigated. It is found that appropriate Ce can modify the inclusions into Ce-containing inclusions in AISI 440C, reduce the precipitation of primary carbide network in the steel, and refine the solidification structure of the as-cast steel.

Numerical Investigation on Coalescence Behavior of Liquid Inclusion Particles in Argon Bubble Wake Flow

  • First Published: 30 January 2024
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The collision, coalescence as well as floatation of bubble–inclusion coexisting system is fully studied through a new mathematical model. The velocity of the bubbles is affected by their deformation, which is linked to the Weber number. The coalescence time of inclusions shortens with the increase in the surface tension or the decrease in viscosity.

Effect of Ladle Shroud Blockage on Flow Dynamics and Cleanliness of Steel in Coupled Ladle–Shroud–Tundish System

  • First Published: 01 February 2024
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A numerical simulation of the coupled ladle–shroud–tundish system is developed to analyze the effect of the obstruction of the shroud clogging on fluid dynamics, thermal behavior, and steel cleanliness. The results show that clogging modifies the fluid dynamics pattern and temperature distribution in the tundish, decreasing its efficiency for removing inclusions by up 25% for particles of 10 μm.

Effect of Second Phase on the Tensile Properties of a High-Mn High-Al Austenitic Lightweight Steel Processed by Thin-Strip Casting

  • First Published: 01 February 2024
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This work investigates the effect of second phase on the tensile properties of a high-Mn high-Al austenitic lightweight steel processed by thin-strip casting. The short-range ordered phase improves both strength and toughness with less deterioration in strain hardening rate, while the nanosized κ phase greatly improves strength at the expense of toughness and strain hardening rate.

Dephosphorization Kinetics of Hot Metal at Low Slag Basicity and Low Temperature under the Different Fe2O3 Addition Amounts

  • First Published: 28 January 2024
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The effect of the Fe2O3 addition amount on the dephosphorization kinetics of hot metal at low slag basicity of about 1.6 and the low temperature of 1623 K is investigated through laboratorial experiments for the double slag converter steelmaking process. With the increase in Fe2O3 addition amount, the dephosphorization is promoted from the kinetic perspective.

Optimization of Process Parameters for 40Cr Steel Continuous Casting Round Bloom with Pulsed Magneto-Oscillation Treatment

  • First Published: 27 January 2024
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A multifield coupling model for pulsed magneto-oscillation (PMO) treatment of continuous casting round bloom is established. The impact of PMO parameters and casting parameters on the solidification process of continuous casting blooms is discussed. The industrial experiments conducted under the recommended parameters yield good results. PMO can improve the quality of continuous casting blooms at high casting speeds.

Development and Application of On-Line Solution Annealing Process for 304 Austenitic Stainless Steel

  • First Published: 01 February 2024
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The practicable method for on-line solution annealing process for 304 austenitic stainless steel is proposed with results from both recrystallization softening experiments and M23C6 precipitation experiments. Industrial tests shows that samples on-line solution-treated with calculated parameters meet the requisite standards.

Difference in Radial Direction of Lumpy Coke Sampling from Raceway of Large Blast Furnaces: Microstructure, Alkali Enrichment, and Solution Loss Reaction

  • First Published: 01 February 2024
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The manuscript investigates radial differences between lumpy coke and raceway coke, changes in structure and composition, and results that alkali metal enrichment, pore structure also differ and are closely linked to the degree of structural ordering, and that alkali metals play a determining role in the reactivity of the coke.

Effect of Austenite Grain Size on Phase Transformation Structure of Low-Carbon Microalloyed Steel

  • First Published: 01 February 2024
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According to the process characteristics and working principle of high heat input welding steel, the continuous cooling phase transition behavior of coarse-grained heat-affected zone and the competitive nucleation mechanism of intracrystalline ferrite are studied. It provides that the prior austenite grain size still has some influence on the effective activation energy of phase transformation during continuous cooling.

Effect of Microstructure on Mechanical Properties of X65MS Welded Pipe Joint

  • First Published: 05 February 2024
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The safety of pipelines depends on the mechanical properties of welded joints. This study investigates the relationship between microstructure and mechanical properties of welded joints in X65MS pipeline steel for sour service. The welding cycle results in a microstructure of acicular ferrite, granular bainite, and polygonal ferrite, with varying hardness and impact energy across different zones.

A Novel Classification Method for Carbide Grade by Using a New Shape Factor with Stress Distribution Analysis

  • First Published: 30 January 2024
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This study aims to explore a new carbide shape factor φ sc $\left(\varphi\right)_{\text{sc}}$ and a novel classification method to quantify the influence of geometry shape on the stress concentration of microstructure. The stress concentration coefficient linearly increases with increasing the shape factor in the double logarithmic coordinate. The linear relationship between the shape factor and the hardness is established.