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Interdiffusion of Solute Elements in the α-Fe Phase of the Fe–Cr–Mo and Fe–Cr–Si Ternary Systems ISIJ Int. (IF 1.8) Pub Date : 2024-03-15 Dosung Lee, Mariko Tsuyuguchi, Manabu Watanabe, Yaw Wang Chai, Takako Yamashita, Shin Ishikawa, Yoshisato Kimura
To understand the interdiffusion of alloying elements in the α-Fe phase of the Fe–Cr–Mo and Fe–Cr–Si ternary systems, interdiffusion coefficients are determined. The main ( and , i: Cr and j: Mo or Si in the present study) and cross ( and ) interdiffusion coefficients in the ternary systems were determined by the Whittle–Green method. From main interdiffusion coefficients in the ternary systems at
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Relationship between the nonuniformity of packed structure and fluid permeability in a model scrap preheating vessel ISIJ Int. (IF 1.8) Pub Date : 2024-03-18 Manabu Tange, Haruki Fujii, Haruto Fujizoe, Yasuo Kishimoto, Arihiro Matsunaga, Yoshihiro Miwa, Koichi Tsutsumi
Recycled scrap is used as a raw material in an electric arc furnace (EAF). Certain EAF systems preheat the scrap using its exhaust gas to save energy. However, the actual operations cannot recover sufficient thermal energy of gas owing to non-uniform flow distribution such as blow-out and stagnation to cause the portion that is not melted. This study investigated the relationship between packed structure
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Predictive Modeling of Strip Temperature in Continuous Annealing Furnace: An Improved Optimization Algorithm ISIJ Int. (IF 1.8) Pub Date : 2024-03-15 Hongfei Ding, Hao Shen, Qian Xie
Taking full account of the complex mechanism of the continuous annealing furnace (CAF) production process and the difficulty in establishing an accurate mathematical model, this paper adopts a quantum particle swarm optimization (QPSO) algorithm to optimize the parameters of the radial basis function (RBF) neural network which used to predict the model of strip temperature in CAF. Firstly, to improve
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Quantification of Changes in Lattice Defect Density in BCC Iron during Plastic Deformation Using Electrical Resistivity Measurements ISIJ Int. (IF 1.8) Pub Date : 2024-03-15 Soichiro Takenaka, Ryohei Takahashi, Kazuhiro Ishikawa, Yoji Miyajima
Change in lattice defects density in bcc pure iron due to tensile deformation was quantified by using both electrical resistivity measurements and X-ray diffraction (XRD). As bcc pure irons, ultra-low carbon steel (ULCS) and interstitial free (IF) steel are used as the model specimen. Dislocation density evaluated using Williamson Hall method with XRD shows the saturation with the value of around 3
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Effects of the Cr and Ni concentrations on the fatigue and corrosion resistances of Fe−Mn−Cr−Ni−Si alloys for seismic damping applications ISIJ Int. (IF 1.8) Pub Date : 2024-03-14 Fumiyoshi Yoshinaka, Yusuke Tsutsumi, Tomoya Nagira, Susumu Takamori, Satoshi Emura, Takahiro Sawaguchi, Hideki Katayama, Terumi Nakamura, Yasuhiko Inoue, Susumu Motomura, Atsumichi Kushibe
Previous research has shown that Fe–Mn–Cr–Ni–Si alloys offer excellent low-cycle fatigue resistance via reversible bidirectional transformation between face-centered cubic (FCC) γ-austenite and hexagonal closed-packed (HCP) ε-martensite. The alloy shows superior low-cycle fatigue life and is used for seismic damping applications, but there have been concerns over their resistance to highly corrosive
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Enhanced Impingement Characteristics of Supersonic Oxygen Jets on Molten Bath Using a Multi-nozzle Oxygen Lance in a Converter ISIJ Int. (IF 1.8) Pub Date : 2024-03-15 Junyi Hu, Qijia Yang, Shiliang Yang, Hongshi Yu, Hua Wang
In the context of supersonic oxygen jets impinging on the bath surface, understanding the gas-bath interaction mechanism is of paramount importance for optimizing lance design in the converter for steelmaking process. This study employs a coupled VOF model and realizable k-ε turbulence model to simulate the gas/metal/slag turbulent flow in a 180 t converter for exploring the essential aspects such
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Separation of Phosphorus from Phosphorus-concentrated Steelmaking Slag ISIJ Int. (IF 1.8) Pub Date : 2024-03-15 Takayuki Iwama, Ryo Inoue, Kenji Nakase, Shigeru Ueda
Since 10 million tons of steelmaking slag, which contains a few percent of phosphorus, are annually produced, the phosphorus amount in the slag is equivalent to the annual import volume of phosphorus rock in Japan. Therefore, the steelmaking slag is attracting attention as a potential phosphorus resources. Phosphorus-concentrated slag obtained by the dephosphorization reaction between high phosphorus
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Influence of Crystal Structure and Chemical Composition on the Reducibility of Silico-Ferrite of Calcium and Aluminum in CO–CO2–H2–H2O Atmosphere ISIJ Int. (IF 1.8) Pub Date : 2024-03-15 Daisuke Maruoka, Shojiro Mataoka, Eiki Kasai, Taichi Murakami
In this study, influence of crystal structure and chemical composition for Silico-Ferrite of Calcium and Aluminum (SFCA) on its reducibility are examined. Eight types of powder samples containing SFCA and SFCA-I were prepared using chemical reagents by the heat treatments in air. The samples were heated up to 800°C in the different atmospheres of CO–CO2–H2–H2O systems. The reducibility of the samples
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Exploring the Relationship Between Fe-rich SFCA and SFCA-III and Their Presence in Sinter Strand and Pot-grate Sinter ISIJ Int. (IF 1.8) Pub Date : 2024-03-15 Nathan A. S. Webster, Mark I. Pownceby
Using the X-ray diffraction (XRD) patterns collected on the products of laboratory furnace experiments performed on a synthetic iron ore sinter mixture with composition 77.36% Fe2O3, 14.08% CaO, 3.56% SiO2 and 5.00% Al2O3, it is demonstrated that the previously reported Fe-rich SFCA phase has the same crystal structure as triclinic SFCA-III. Therefore, the four principal members of the silico-ferrite
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In-situ Laser Ultrasonics Measurements of Ferrite Formation during Stepped Cooling of A 0.1C-2Mn Dual Phase Steel ISIJ Int. (IF 1.8) Pub Date : 2024-03-15 Nobumasa Hayashi, Mariana C. M. Rodrigues, Matthias Militzer
Dual-phase (DP) steels are advanced high-strength steels used in automotive design. To achieve optimal mechanical properties the control of phase transformations during processing is paramount, e.g. for hot-rolled DP steels a desired ferrite fraction is required to form during run-out table cooling. Thus, sensor technologies such as laser ultrasonics (LUS) are of considerable interest that can in-situ
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Effects of Alloying Element on Bainitic Transformation in Fe-0.3N Alloy ISIJ Int. (IF 1.8) Pub Date : 2024-03-15 Mitsutaka Sato, Shota Shimaya, Kazuki Hara, Goro Miyamoto, Tadashi Furuhara
The effects of alloying elements on the bainite transformation behaviors were investigated for Fe-0.3N and Fe-0.3N-1M (M: Si, Cr, Mn, Mo) (mass%) alloys. Nitrogen (N) was introduced into austenite by gas nitriding and subsequent isothermal holding were employed at 500°C. Bainitic ferrite starts to form from the austenite grain boundaries in all alloys. Bainite structure changed from nitride-free bainite
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Effect of Molybdenum Content on the Hardenability and Precipitation Behaviors of Boron Steel Austenitized at High Temperatures ISIJ Int. (IF 1.8) Pub Date : 2024-03-15 Kyohei Ishikawa, Masaaki Fujioka, Manabu Hoshino, Jun Takahashi, Ryuichi Homma, Kohsaku Ushioda
The effect of molybdenum (Mo) contents on hardenability and precipitation behaviors in Mo–B simultaneously added steels were investigated placing a focus on high austenitizing temperature. The hardenability of 0.5% Mo - 11 ppm B steel austenitized at 1150°C was decreased compared with that austenitized at 950°C, whereas 1.0% Mo - 10 ppm B and 1.5% Mo - 9 ppm B steels were less affected by high austenitizing
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Local Yield Stress and Its Unusual Independence on Multi-axial Stress States during Lüders Deformation of Medium-Mn, High-strength Steel ISIJ Int. (IF 1.8) Pub Date : 2024-03-15 Takashi Matsuno, Koki Furukawa, Yoshitaka Okitsu, Motomichi Koyama, Toshihiro Tsuchiyama
Medium-manganese steel that undergoes Lüders deformation exhibits good uniform elongation owing to large elongation with a yield plateau. To accurately predict the deformation behavior in engineering applications, the yield stresses of medium-manganese steel (5% Mn), exhibiting the transformation-induced plasticity (TRIP) effect were investigated during elongation under a multi-axial stress state (MSS)
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Multiscale Finite Element Analysis of Yield-point Phenomenon in Ferrite–Pearlite Duplex Steels ISIJ Int. (IF 1.8) Pub Date : 2024-03-15 Shinnosuke Yanagawa, Ikumu Watanabe
The yield-point phenomena in ferrite–pearlite duplex steels were investigated using multiscale computational simulations. In these multiscale simulations, the stress–strain relationship of the ferrite phase was characterized by an elastoplastic constitutive model considering the stress-drop behavior, and its material constants were determined by minimizing the residual error between a computational
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Development of Innovative Gasification Process of Used Plastic by Using Fluidized Bed ISIJ Int. (IF 1.8) Pub Date : 2024-03-15 Koichi Momono, Jun Ishii, Seiji Hosohara, Hideo Kijima
Used plastic waste flowing into oceans has become a worldwide problem. Since international trade in used plastics has been regulated in recent years, a large amount of used plastic now requires domestic disposal. On the other hand, used plastics with a high calorific value could be used as an energy source. Therefore, the authors developed a new used plastic gasification process utilizing a fluidized
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Use of X-ray CT imaging to quantitatively analyze the effects of the pore morphology on the tensile properties of CP-Ti L-PBF materials ISIJ Int. (IF 1.8) Pub Date : 2024-03-14 Yuji Shigeta, Naoyuki Nomura, Katsuyoshi Kondoh, Kentaro Uesugi, Masato Hoshino, Masatoshi Aramaki, Yukiko Ozaki
Controlling the shape, size, and arrangement of residual defects (pores) in additive-manufactured materials is essential for improving their strength and reliability. However, quantifying the shape and arrangement of individual pores in such materials remains a challenge. This study aimed to clarify the effect of pore configurations that determine the tensile properties of laser powder-based fusion
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Comparison of hydrochar and anthracite as reducing agents for direct reduction of hematite ISIJ Int. (IF 1.8) Pub Date : 2024-03-12 Yu-Chiao Lu, Andrey V. Karasev, Björn Glaser, Chuan Wang
The substitution of fossil coal with biocarbon in the metallurgical processes can help to decrease fossil CO2 emissions. Biocarbon's characteristics, such as high volatile matter contents and high reactivities with CO2, are beneficial for increasing the reduction degrees and reduction rates of iron oxides in carbon composite agglomerates (CCA). This study compared the reduction of hematite by of two
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Efficient finite element simulation of cold rolled strip coiling process considering additional contact deformation between layers ISIJ Int. (IF 1.8) Pub Date : 2024-03-08 Meng Dai, Shujie Liang, Ping Qiu, Hong Xiao
When analyzing the strip coiling process, the finite element (FE) method is closer to the actual working conditions compared to the analytical method. However, due to the large number of strip elements and contact elements, it often leads to problems such as long-time consumption and non-convergence. Meanwhile, traditional FE methods are still unable to solve the problem of additional contact deformation
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Effect of Submerged Entry Nozzle Structure on Fluid Flow, Slag Entrainment, and Solidification Process in a Slab Continuous Casting Mold ISIJ Int. (IF 1.8) Pub Date : 2024-03-08 Rui Xu, Haitao Ling, Xiang Tian, Lei Ren, Lizhong Chang, Shengtao Qiu
The fluid flow and slag entrainment in a slab continuous casting mold were investigated by establishing a full-scale water model. Meanwhile, the heat transfer and solidification process of liquid steel in the mold were studied through numerical simulation. The effect of two different submerged entry nozzles (SENs) was compared and analyzed, named as original SEN and L1 SEN, respectively. The results
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Effect of rare earth La–Ce on solidification structure of 3.2%Si-0.9%Al non-oriented silicon steel ISIJ Int. (IF 1.8) Pub Date : 2024-03-08 Cheng Song, Li Xiang, Chao Shi, Jialong Qiao, Jianfeng Liu, Shengtao Qiu
The effect of rare earth on the solidification structure of 3.2%Si-0.9%Al non-oriented silicon steel was investigated using industrial trials. The outputs demonstrated that increasing rare earth content leads to a decrease in the average size of equiaxed crystals in the casting billets. In order to further understand the rare earth on the grain refinement of δ-ferrite, the conventional inclusion detection
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Effect of Residual Stress on Hydrogen Embrittlement at Sheared Edge ISIJ Int. (IF 1.8) Pub Date : 2024-02-28 Yuji Sakiyama, Tomohiko Omura, Takashi Yasutomi, Takayuki Harano, Kengo Noami
The residual stresses at a circular punched end face in tempered martensitic high-strength steel sheets were investigated using triaxial stress analysis via X-ray diffraction. The maximum principal stress and its direction were calculated from the measured nine stress components. The relationship between the directions of the maximum principal stress and hydrogen cracks was verified by generating hydrogen
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Hydrogen Embrittlement Property of a 1.5 GPa Dual-Phase Steel Evaluated Using U-bending Test: A Comparison with Tempered Martensitic Steel with Identical Tensile Strength ISIJ Int. (IF 1.8) Pub Date : 2024-02-28 Shuya Chiba, Motomichi Koyama, Tomohiko Hojo, Saya Ajito, Yuki Shibayama, Rama Srinivas Varanasi, Eiji Akiyama
The hydrogen embrittlement susceptibilities of 1.5 GPa-class dual-phase (DP) and tempered martensitic steels were comparatively evaluated using U-bending test. The U-bending tests showed no differences in hydrogen embrittlement susceptibility between the two steels. The martensitic and DP steels exhibited intergranular and quasi-cleavage fractures, respectively. The crack initiation site reached the
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Isothermal reduction kinetics of the mixture of iron carbon agglomerates and sinter ISIJ Int. (IF 1.8) Pub Date : 2024-03-01 Jiwei Bao, Mansheng Chu, Jue Tang, Lifeng Zhang
The effect of iron carbon agglomerates (ICA) on the reduction of sinter is very important to blast furnace (BF) ironmaking. In this paper, the isothermal reduction kinetics of ICA-sinters mixture and the coupling synergistic mechanism between ICA and sinter are comprehensively studied. The results show that the early stage of isothermal reduction of ICA-sinters mixture is jointly controlled by the
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Direct Electrodeposition of High-Purity Iron from Fe2O3 in Molten Calcium Chloride ISIJ Int. (IF 1.8) Pub Date : 2024-03-01 Zhongya Pang, Jinjian Li, Shun Chen, Xueqiang Zhang, Feng Tian, Guangshi Li, Shujuan Wang, Xing Yu, Chaoyi Chen, Qian Xu, Xionggang Lu, Xingli Zou
The low-cost production of high-purity metallic iron is of great practical importance. Herein, we report the direct production of high-purity metallic iron (99.92 %) via a one-step electrochemical strategy in molten CaCl2-CaO-Fe2O3 system at 850 oC. The involved CaO-assisted dissolution of Fe2O3 and electrodeposition mechanism were systematically studied, and the obtained iron products were characterized
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Effect of Ammonium Thiocyanate on Hydrogen Absorption by Cathodic Charging in Weak Alkaline Solution ISIJ Int. (IF 1.8) Pub Date : 2024-02-28 Takuya Kamisho, Ryuta Ishii, Masayuki Tsuda
To clarify the mechanism underlying hydrogen absorption enhancement by adding ammonium thiocyanate (NH4SCN) during cathodic charging in a weak alkaline solution, we constructed a kinetic model of the hydrogen evolution reaction and the hydrogen absorption reaction and performed analysis by fitting the kinetic model to the cathodic current density and steady-state permeation current density obtained
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Effect of Hydrogen Concentration on Nanoindentation Softening and Hardening in Iron: Ferrite Phase of S25C and Single-crystal Fe-3wt.%Si ISIJ Int. (IF 1.8) Pub Date : 2024-02-28 Shinya Taketomi, Toshiki Taniguchi, Hiroki Yamamoto, Seiya Hagihara, Sadahiro Tsurekawa, Ryosuke Matsumoto
Plastic deformation is key to understanding hydrogen embrittlement in steels. Although macroscopic to microscopic observations and analyses have reported softening and hardening behavior in the presence of hydrogen, the mechanisms causing these effects and the overall mechanisms remain unclear. Therefore, this study applies nanoindentation tests to the ferrite phase of bcc-structured polycrystalline
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Nucleation of Nano-sized Prismatic Dislocation Loop from Spherical Vacancy Clusters in α-iron: An Atomic-scale Study ISIJ Int. (IF 1.8) Pub Date : 2024-02-28 Mugilgeethan Vijendran, Ryosuke Matsumoto
The concentration of vacancy-type defects in α-iron is increased by plastic deformation and the presence of hydrogen. This leads to the accumulation of monovacancies, either in the form of planar vacancy clusters (VCs) or small voids. The prismatic dislocation loop (PDL) can nucleate from VC as vacancies agglomerate into two-dimensional (2D) VCs and collapse due to attractive force between two interior
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Effect of Iron Oxide Dissolution on Thermochemical Property of Solid Solution between Ca2SiO4 and Ca3P2O8 at 1573 K ISIJ Int. (IF 1.8) Pub Date : 2024-02-29 Keijiro Saito, Yoshiyuki Makino, Masakatsu Hasegawa
The key to a better understanding of phosphorus removal from hot metal is to know the thermochemical properties of solid solution between Ca2SiO4 and Ca3P2O8. Although the solid solutions would inevitably incorporate iron oxide in steelmaking slags, there is a still lack of knowledge about the solid solutions containing iron oxide. The present study focused on the effect of FeO dissolution on the activities
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Constitutive Description of Flow Curve for Duplex Titanium Alloy for Hot Forming under Elevated Temperature ISIJ Int. (IF 1.8) Pub Date : 2024-02-29 Yuki Shimomura, Hyung-Won Park, Hyeon-Woo Park, Yuji Sato, Jun Yanagimoto
A novel integrated constitutive equation of the flow curve for Ti–6Al–4V alloys is proposed by incorporating the effects of phase fraction in the hot-forging temperature range. The flow curve was obtained using hot-compression tests in the temperature range of 750–1050 °C and strain rate range of 1–25 s-1. The effects of friction and deformation heat generated during compression were corrected using
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Hydrogen trapping and precipitation of alloy carbides in molybdenum added steels and vanadium added steels ISIJ Int. (IF 1.8) Pub Date : 2024-02-29 Shunsuke Taniguchi, Miyuri Kameya, Yukiko Kobayashi, Kazuma Ito, Shingo Yamasaki
Martensitic steels of Fe-0.1%C-2%Mn-1.6%Mo and Fe-0.1%C-2%Mn-0.2%V alloys were subjected to tempering at 873 K to investigate the hydrogen trapping of Mo and V carbides. We analyzed the alloy carbides in detail via atomic-resolution scanning transmission electron microscopy and atom probe tomography, and evaluated hydrogen trapping energy via ab initio calculations. The hydrogen content of the Mo-added
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Effects of the Addition of Alloying Elements on Hydrogen Diffusion and Hydrogen Embrittlement in Martensitic Steel ISIJ Int. (IF 1.8) Pub Date : 2024-02-28 Tomohiko Omura, Takumi Oyama
We investigated the effects of the substitutional alloying elements on the hydrogen diffusion and embrittlement properties of as-quenched and subsequently tempered martensitic steels containing Cr, Mo, Mn, and Ni. Hydrogen diffusion coefficients (Ds) of the as-quenched steels, measured via hydrogen permeation tests under cathodic hydrogen charging at 24°C, reduce as a function of the concentration
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Effect of Stretch-forming on Hydrogen Diffusion Behavior in High-strength Steel Sheet ISIJ Int. (IF 1.8) Pub Date : 2024-02-28 Hayato Nishimura, Saya Ajito, Tomohiko Hojo, Motomichi Koyama, Ken-ichi Fujita, Yuki Shibayama, Hiroshi Kakinuma, Eiji Akiyama
The hydrogen diffusion behavior in a tempered martensitic steel sheet with 1-GPa grade tensile strength was investigated using a newly developed hydrogen visualization technique with an Ir complex, whose color changes from yellow to orange due to its reaction with hydrogen. Hydrogen permeation through the steel sheet could be monitored via the color change of the Ir complex. Furthermore, the breakthrough
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Carbide Precipitation and Hydrogen Trapping Behavior in Mo and V Added Tempered Martensitic Steel ISIJ Int. (IF 1.8) Pub Date : 2024-02-28 Miyuri Kameya, Shunsuke Taniguchi, Yukiko Kobayashi, Naoki Matsui, Shingo Yamasaki
To investigate the hydrogen trapping effect of the combined addition of V to Mo-added steel, 0.1C-2Mn-1.6Mo mass% steel (Steel A) and 0.1C-2Mn-1.6Mo-0.2V mass% steel (Steel B) were prepared, quenched, and tempered at 873 K. The hydrogen trapping effect was investigated by thermal desorption hydrogen analysis of hydrogen-charged specimens, and Steel B showed a higher hydrogen trapping capacity than
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Visualization of Hydrogen and Hydrogen-induced Defects in Tensile-deformed Pure Iron Using Hydrogen Microprint and Tritium Autoradiography ISIJ Int. (IF 1.8) Pub Date : 2024-02-28 Toshiaki Manaka, Goroh Itoh, Junya Kobayashi, Shigeru Kuramoto, Yuji Hatano
To understand the process and mechanism for hydrogen embrittlement in steels, visualization of the location of hydrogen is essential. In the present study, two visualization techniques, hydrogen microprint technique (HMT) and tritium autoradiography (TAR), were applied to a pure iron sheet 20% tensile-deformed with cathodic hydrogen charging. When the specimen was covered with photographic emulsion
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Relationship between Three-dimensional Crack Morphology and Macroscopic Mechanical Properties of Hydrogen-related Fracture in Martensitic Steel ISIJ Int. (IF 1.8) Pub Date : 2024-02-28 Akinobu Shibata, Yazid Madi, Jacques Besson, Akiko Nakamura, Taku Moronaga, Kazuho Okada, Ivan Gutierrez-urrutia, Toru Hara
In the present study, several parameters related to crack morphology in the case of hydrogen embrittlement were estimated by X-ray computed tomography and correlated with the macroscopic mechanical responses (J-integral and tearing modulus) obtained from the fracture mechanics tests. Even when the hydrogen content was high up to 4.00 wt ppm, unstable premature fracture did not immediately occur, and
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Comparison of Crack Initiation Sites and Main Factors Causing Hydrogen Embrittlement of Tempered Martensitic Steels with Different Carbide Precipitation States ISIJ Int. (IF 1.8) Pub Date : 2024-02-28 Naoki Uemura, Takahiro Chiba, Kenichi Takai
The dependence of crack initiation sites and main factors causing hydrogen embrittlement fracture on carbide precipitation states has been investigated for tempered martensitic steels with the same tensile strength of 1450 MPa. Notched specimens charged with hydrogen were stressed until just before fracture and subsequently unloaded. The crack initiation site exhibited intergranular (IG) fracture at
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Hydrogen Content Dependence of Crack Initiation and Propagation Behavior of Hydrogen Embrittlement in Tempered Martensitic Steel ISIJ Int. (IF 1.8) Pub Date : 2024-02-28 Naoki Uemura, Takahiro Chiba, Kei Saito, Kenichi Takai
Crack initiation and propagation behavior in hydrogen embrittlement fracture of tempered martensitic steel at a low hydrogen content was compared with the results at a high hydrogen content. Notched specimens charged with a low hydrogen content of 0.18 ppm and a high hydrogen content of 5.3 ppm were stressed and unloaded immediately upon reaching the maximum stress in tensile tests. At the low hydrogen
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Grain Refinement Effect on Resistance to Hydrogen-assisted Crack Growth in Equiatomic CoCrFeNi High-entropy Alloy with Different H Charging Conditions ISIJ Int. (IF 1.8) Pub Date : 2024-02-28 Taein Kong, Haoyu Wang, Taekyung Lee, Motomichi Koyama, Eiji Akiyama
The hydrogen embrittlement (HE) resistance of a fine-grained equiatomic CoCrFeNi high-entropy alloy (HEA) is investigated via tensile testing under electrochemical H charging. The HE behavior is compared with that of HEA specimens charged with 100 MPa of H gas. The fine-grained HEA shows > 40% elongation with a tensile strength of ~800 MPa under electrochemical H charging. Meanwhile, H gas-charged
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Hydrogen Effects on Fracture Resistances of Bulk Cementite Evaluated by in-situ Microbending Test during Cathodic Hydrogen Charging ISIJ Int. (IF 1.8) Pub Date : 2024-02-28 Kota Tomatsu, Masahiro Sasaki, Takahiro Aoki, Tomohiko Omura
Hydrogen absorption characteristics and mechanical properties in hydrogen environment of cementite were evaluated by low-temperature thermal desorption analysis and in-situ microbending tests during cathodic hydrogen charging using bulk cementite plates obtained through a vacuum carburizing process. In the low-temperature thermal desorption analysis, no hydrogen desorption was identified up to 1073
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Overview of Hydrogen Effects on γ−ε Martensitic Transformation in Steels ISIJ Int. (IF 1.8) Pub Date : 2024-02-28 Motomichi Koyama, Satoshi Iikubo, Rama Srinivas Varanasi
This paper presents an overview of our recent works on the effects of hydrogen on γ-ε martensitic transformations in steels. The study first discusses how hydrogen impacts these transformations. While hydrogen suppresses thermally-induced γ–ε martensitic transformation, it increases the fraction and number density of deformation-induced ε-martensite and decreases its thickness. Secondly, we discuss
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Delayed Fracture Enhanced by Martensite Transformed from Retained Austenite in Ultra-high Strength Steel Sheet ISIJ Int. (IF 1.8) Pub Date : 2024-02-28 Katsutoshi Takashima, Takamasa Nishimura, Ken’ichi Yokoyama, Yoshimasa Funakawa
Delayed fracture of ultra-high strength complex phase (CP) steel sheets containing either a small amount of retained austenite or substantially no retained austenite was investigated by a sustained tensile-loading test during hydrogen charging. The microstructures of both specimens are composed of martensite and bainitic ferrite. Most of the retained austenite exists as a secondary phase in the bainitic
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Examples of Fractured Steel Parts during Actual Usage due to Hydrogen Embrittlement and Consideration Regarding the Behavior of Hydrogen at the Prior Austenite Grain Boundary ISIJ Int. (IF 1.8) Pub Date : 2024-02-28 Hiroshi Yaguchi
Steel parts fractured during actual use were investigated, and the mechanism of fracture for some of them was attributed to hydrogen embrittlement. This article describes a summary of the observation results fractured by hydrogen embrittlement. Fracture occurred under tensile stress within the elastic limit including residual stress. Most of the parts had a martensitic microstructure, and intergranular
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Influence of High Concentration Vacancy-Type Defects on the Mobility of Edge Dislocation in α-Iron: An Atomistic Investigation ISIJ Int. (IF 1.8) Pub Date : 2024-02-28 Sunday Temitope Oyinbo, Ryosuke Matsumoto
Many vacancy-type defects (vacancy, vacancy clusters, and hydrogen-vacancy complexes) are generated in metals by plastic deformation in hydrogen environments. In this study, we use extensive molecular dynamics calculations based on a highly accurate interatomic potential to examine how vacancy-type defects affect the mobilities of edge dislocations in α-iron at a temperature range of 300–500 K and
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Assessing the banding degree of martensite in the bainite matrix through EPMA ISIJ Int. (IF 1.8) Pub Date : 2024-02-27 Yang Meng, Chunlian Yan, Juan Wen, Xinhua Ju
Due to the difficulty of distinguishing the grain boundaries between martensite and bainite in fast-cooling microstructures, few good methods were reported to accurately assess the banding degree of martensite or bainite. In present work, a novel method has been developed to meet this challenge. The hot rolled bars of drill steel 23CrMoNi, which had martensite bands distributed in the bainite matrix
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Dissolution of Carbon-Containing Species in CaO-SiO2-Al2O3 Slag ISIJ Int. (IF 1.8) Pub Date : 2024-02-27 Qiuju Li, Cong Liang, Bowen Han
The acceleration of the carburizing and melting processes in reduced iron is critical for reducing energy consumption and CO2 emissions produced by the steel industry. The aims of the study were to clarify the carbon dissolution reactions and diffusion processes in molten slag. A combined approach utilizing Raman spectroscopy and XPS was employed to investigate the relationship between carbon-containing
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Effect of biocarbon addition on metallurgical properties of mill scale-based auger pressing briquettes ISIJ Int. (IF 1.8) Pub Date : 2024-02-26 Olli Vitikka, Mikko Iljana, Anne Heikkilä, Illia Tkalenko, Oleksii Kovtun, Nikita Koriuchev, Daniel Shehovsov, Timo Fabritius
This work focused on the usage of bio-based and secondary iron and steelmaking raw materials. Auger pressing briquettes, cold-bonded agglomerates made from by-products, mainly mill scale (80%), were successfully tested in industrial-scale blast furnace (BF) trials. The briquettes from industrial production were studied in two different laboratory-scale reduction experiments to compare them to laboratory-made
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Liquid-Liquid Phase Separation and Phase Distribution in CaO-P2O5-FeO Slag for Phosphorus Recovery ISIJ Int. (IF 1.8) Pub Date : 2024-02-22 Yu-ichi Uchida, Kenji Nakase, Katsunori Takahashi
Supposing to utilize the slag with high P2O5 content as a new phosphorus resource produced from a novel steelmaking process, a fundamental investigation was carried out with particular focus on spontaneous liquid-liquid phase separation occurring in the system CaO-P2O5-FeO for effective phosphorus recovery. At 1773K, two types of phase separation, which is a double-layered or a dispersed structure
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Effect of glycerol mechanical excitation on the phase evolution and hydration activity of steel slag ISIJ Int. (IF 1.8) Pub Date : 2024-02-21 Peng Yao Liu, Guo Peng Li, Meng Jie Tao, Xi Zhang, Jun Guo Li, Shuai Chao, Ya Ling Zhang, Yi Ming Duan, Xin Ning, Chong Yu Niu, Guo Zhang Tang
During the slow cooling process of steel slag, the crystals of inert mineral phases (C2F, RO phases) and active mineral phases (C2S, C3S) adhere and grow, and the irregular interlocking, embedding, filling, stacking, and coating between mineral phases seriously affect the hydration activity of active mineral phases in steel slag. Therefore, this article selects glycerol (C3H8O3) as a grinding aid to
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Kinetics analysis of iron oxide reduction by solid carbon in HIsmelt ironmaking slag ISIJ Int. (IF 1.8) Pub Date : 2024-02-19 Zhenyang Wang, Ruishuai Si, Jing Pang, Jixiang Han, Wei Ren, Ziluo Chen, Jianliang Zhang, Shushi Zhang, Dewen Jiang, Song Zhang
The HIsmelt process is a new molten reduction ironmaking technology with lower energy consumption and carbon emissions than the traditional blast furnace ironmaking route. In the HIsmelt smelting process, the reaction process between solid carbon and iron-bearing slag has its own characteristics. To investigate the kinetic mechanism of iron oxide reduction in slag, the degree of conversion was characterized
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Effect of Nano-sized Cu-Rich Phase on Microbiological Corrosion Behavior of Cu and Ni-Added Steel for Oil Country Tubular Goods ISIJ Int. (IF 1.8) Pub Date : 2024-02-19 Xianbo Shi, Yunpeng Zeng, Yi Ren, Wei Yan, Xu Yang, Guanghui Wu, Yiyin Shan, Ke Yang
The Cu-bearing antibacterial low-alloyed steel pipe is a new strategy to mitigate microbiologically influenced corrosion (MIC) for oil and gas industry. It can effectively alleviate the occurrence of bacterial corrosion, but cannot avoid the MIC totally. To enhance the resistance to MIC of Cu-bearing low-alloyed steel, the MIC behavior of a Cu and Ni-added experimental steel with different nano-sized
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Function of Solidification Pressure on the Rising and Breakup of Nitrogen Bubbles in Molten Steel ISIJ Int. (IF 1.8) Pub Date : 2024-02-15 Hongchun Zhu, Zhuowen Ni, Huabing Li, Zhiyu He, Yu Wang, Hao Feng, Zhouhua Jiang
In this study, the rising and breakup of nitrogen bubbles in high nitrogen molten steel considering different solidification pressure has been numerically simulated by the VOF model verified comparing velocity and deformation of bubbles in water. Rising process of nitrogen bubble in the molten steel is divided into three stages. In stage I, nitrogen bubble experiences an inward depression and splits
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Turbulent Agglomeration of Polydispersed Particles in a Liquid ISIJ Int. (IF 1.8) Pub Date : 2024-02-15 Hirotada Arai, Takashi Sugitani, Hiroki Ota, Sei Kimura
In this study, water model experiments were performed using a mechanically agitated vessel, and a mathematical model was developed to investigate the effect of the size distribution of inclusions on turbulent agglomeration behavior. A 3 mol L−1 KCl aqueous solution and two types of polydispersed acrylic particles with different average particle sizes were used in the water model experiments. Furthermore
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Predicting Hot-rolled Strip Crown Using a Hybrid Machine Learning Model ISIJ Int. (IF 1.8) Pub Date : 2024-02-15 Yafeng Ji, Yu Wen, Wen Peng, Jie Sun
The stability of crown is a crucial factor in ensuring the quality of hot-rolled strips. In this study, a hybrid model based on ensemble learning is developed, incorporating four reliable ML models, namely support vector machine (SVM), gaussian process regression (GPR), artificial neural network (ANN), and random forest (RF). To enhance the accuracy and interpretability of the resulting crown model
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Effects of Composition and Heat Treatment on CaS Formation in Ferritic Stainless Steel ISIJ Int. (IF 1.8) Pub Date : 2024-02-15 Shigeru Kaneko, Shigeo Fukumoto
The formation of CaS around CaO–Al2O3 in ferritic stainless steel was investigated. CaS was observed in the samples after heat treatment, although it was not detected in cast ingots. Al and S contents affect the precipitation of CaS because of the following reaction: 2[Al]+3[S]+3CaO=Al2O3+3CaS. The formation of CaS cannot be predicted by thermodynamic calculation. The growth of CaS during heat treatment
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Challenges in Materials Integration ISIJ Int. (IF 1.8) Pub Date : 2024-02-15 Masahiko Demura
Materials Integration is the concept of accelerating materials development by linking processing, structure, property, and performance (PSPP) on a computer using any types of models such as theoretical, empirical, numerical-simulation, and machine learning models. In the first and second phases of Cross-ministerial Strategic Innovation Promotion Program in Cabinet Office, Japan, we have developed a
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Estimation of Electrical Conductivity of Molten Multicomponent Slag by Neural Network Computation ISIJ Int. (IF 1.8) Pub Date : 2024-02-15 Sunglock Lim, Yuki Nobe, Masashi Nakamoto, Kiyoshi Fuji-ta, Toshihiro Tanaka
Information on the electrical conductivity of high-temperature molten oxides can be used as very useful information not only for conventional metallurgical processes on the Earth, but also for the development of extraterrestrial resources such as lunar soil. The models for estimating electrical conductivity of molten slag developed so far apply only to a limited number of slag systems. In this study
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Effect of Oxygen Enrichment on Melting Behavior in Sintering Process ISIJ Int. (IF 1.8) Pub Date : 2024-02-15 Kenta Takehara, Takahide Higuchi, Tetsuya Yamamoto
In the sintering process, productivity and strength are essential indicators, and it is known that they are closely related to the sintering time and temperature. Since the sintering time and high temperature holding time vary greatly depending on the combustion behavior of coke breeze, various studies have been conducted on the influence of oxygen, which is a critical element in sintering phenomena
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Characteristics of Residual Fine Particles in a Blast Furnace ISIJ Int. (IF 1.8) Pub Date : 2024-02-15 Ji Wu, Cai Liang, Minghui Xie, Xiushi Gan, Zhe Jiang, Qingwen Wei
Fine particles can reduce the blast furnace’s gas and liquid permeability. The residual fine particle sampling and screening of the overhaul blast furnace were carried out to obtain particle size distribution. Chemical analysis, XRD, and SEM-EDS were used to analyze the chemical and phase composition, degree of graphitization, and microstructure to clarify the characteristics and evolution of fine
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Identification of Carbonaceous Materials in Blast Furnace Dust by Micro-Raman Spectroscopy ISIJ Int. (IF 1.8) Pub Date : 2024-02-15 Chong Zou, Yaqi Gao, Shiwei Liu, Ruimeng Shi, Bin Li, Yuan She
Carbonaceous materials (CMs) in blast furnace dust (BFD) contain abundant information about evolution behavior and utilization efficiency of metallurgical coke and injected pulverized coal. A novel method for determination of origin and content of BFD by micro-Raman spectroscopy was proposed in this paper. Ten randomly areas was selected and each one covers an area of 120×120 µm in the surface of briquetting
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Crystal Plasticity Finite-element Simulation of Non-uniform Deformation Behavior at Grain Level of Ultralow Carbon Steel ISIJ Int. (IF 1.8) Pub Date : 2024-02-15 Takayuki Hama, Masashi Oka, Takuna Nishi, Takashi Matsuno, Seiji Hayashi, Kenji Takada, Yoshitaka Okitsu
In this study, deformation behaviors at the grain level of coarse-grained ultralow carbon steel subjected to uniaxial tension and simple shear were simulated by using a crystal plasticity finite-element method. Heterogeneity of strain distributions appeared at the early stage and remained almost unchanged in the following deformation. Localized strain bands occurred at the grain level, but the directions