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Effect of Wettability on Droplet Agglomeration in Two Immiscible Liquids ISIJ Int. (IF 1.8) Pub Date : 2024-04-22 Sunglock Lim, Ikuru Hatakeyama, Masashi Nakamoto, Takeshi Yoshikawa, Toshihiro Tanaka
The agglomeration of droplets dispersed in an immiscible liquid is often an issue in metallurgical processes. To determine the effect of wettability on droplet agglomeration, we conducted (1) wettability and (2) agglomeration experiments using immiscible liquid paraffin and glycerin aqueous solution. In the wettability experiment, a droplet of one liquid was settled on the other liquid and its shape
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Analysis and prediction of sticker breakout based on XGBoost forward iterative model ISIJ Int. (IF 1.8) Pub Date : 2024-04-17 Yu Liu, Zhixin Ma, Xudong Wang, Yali Gao, Man Yao, Zhiqiang Xu, Miao Yu
All 61 sticker breakouts and 183 false sticker breakouts were obtained based on the on-line mould monitoring system during the conventional slab continuous casting. The 16-dimensional temperature characteristics and temperature velocity characteristics of the sticker breakout were extracted. The sticker breakout recognition based on the XGBoost forward iterative model was developed and optimized by
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Effect of mixed gas ratio on cooling performance of impinging jets ISIJ Int. (IF 1.8) Pub Date : 2024-04-17 Hirokazu Kobayashi, Gentaro Takeda, Kenji Katoh, Tatsuro Wakimoto
Gas jet cooling is widely used because the device is simple, oxidation can be prevented, and a uniform cooling capacity can be obtained with thin steel sheets. Because the gas jet cooling ability is affected by the physical properties of the gas such as the mixed gas ratio, a quantitative evaluation of the influence of these factors is very important. However, few studies concerning prediction of the
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The evolutions of microstructure and mechanical properties of the welding heat-affected zone in 800MPa-grade complex phase steel ISIJ Int. (IF 1.8) Pub Date : 2024-04-16 Yue Wang, Xianchun Dong, Yang Yu, Kaiguang Hu, Bing Yu, Shuhai Chen
A thermomechanical simulator Gleeble 3800 was used to simulate the thermal cycles experienced by various heat-affected zones (HAZ) during the welding process. The influence of peak temperature (Tp, 500°C~1320°C) on the hardness, microstructure, precipitates, and properties of complex steel 780FB with microalloyed elements Ti, Nb, and V was systematically studied. The contributions of dislocation strengthening
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Thermodynamic Analysis on Slag/Metal Reactions in Steelmaking Process Using Direct Reduced Iron and Steel Scraps ISIJ Int. (IF 1.8) Pub Date : 2024-04-15 Kengo Kato, Hideki Ono
Hydrogen reduction processes of iron ores are being developed to achieve carbon neutrality. However, high-grade iron ore pellets used in the current direct reduction process will be depleted in the future. On the other hand, steel scraps recovered from society are usually contaminated with tramp elements, which are difficult to remove in the current steel refining processes. To produce high-quality
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Activity of Chromium Oxide in CaO–SiO2–MgO–Al2O3–MnO–CaF2–CrOx Slag for Chromium Reducing Process ISIJ Int. (IF 1.8) Pub Date : 2024-04-15 Chonglin Shi, Zhi Li, Yuxing Liu, Yoshinao Kobayashi
Thermodynamic data of chromium oxide activities in molten slags are important for improvement of the reduction treatment process of chromium oxides in stainless steel slags. The chemical equilibrium experiments were conducted in the present work to measure the activity coefficients of chromium oxides in the CaO–CaF2–MgO–Al2O3–SiO2–MnO–CrOx slags at 1823 K (1550°C) under oxygen partial pressure of 2
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Activity of Iron Oxide in Slag with Nepheline Syenite Added as a Flux ISIJ Int. (IF 1.8) Pub Date : 2024-04-15 Yusaku Sakamoto, Keijiro Saito, Masakatsu Hasegawa
Although fluorspar has been widely used as a flux for steelmaking slag, there is a strong incentive to explore alternatives. As one of the candidates for such substances, “nepheline syenite” has been investigated in terms of slag fluidity and lime dissolution rate. The present study aimed at clarifying the homogeneous liquid region and FexO activities in the CaO–FexO slags with nepheline syenite added
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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 : 2024-04-15 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 1773 K, two types of phase separation, which is a double-layered or a dispersed structure
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Precipitation Behavior of MnS Inclusion in Unidirectionally-Solidified Fe-18Mn-1Al-0.3C Steels ISIJ Int. (IF 1.8) Pub Date : 2024-04-15 Yuewen Fan, Kouki Kameda, Xiaojun Hu, Hiroyuki Matsuura
In order to reasonably control the precipitation of inclusions during solidification in TWIP steels, the precipitation behavior of typical MnS inclusions in high manganese steel was investigated by unidirectional solidification experiments. Through the combined analyses using ASEM-EDS, optical microscope, and thermodynamic calculation, it was found that Mn concentration in the liquid metal region were
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Dissolution of Carbon-Containing Species in CaO–SiO2–Al2O3 Slag ISIJ Int. (IF 1.8) Pub Date : 2024-04-15 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 Iron Oxide Dissolution on Thermochemical Property of Solid Solution between Ca2SiO4 and Ca3P2O8 at 1573 K ISIJ Int. (IF 1.8) Pub Date : 2024-04-15 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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Direct Electrodeposition of High-Purity Iron from Fe2O3 in Molten Calcium Chloride ISIJ Int. (IF 1.8) Pub Date : 2024-04-15 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°C. The involved CaO-assisted dissolution of Fe2O3 and electrodeposition mechanism were systematically studied, and the obtained iron products were characterized
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Development of Innovative Gasification Process of Used Plastic by Using Fluidized Bed ISIJ Int. (IF 1.8) Pub Date : 2024-04-15 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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Effect of Biocarbon Addition on Metallurgical Properties of Mill Scale-Based Auger Pressing Briquettes ISIJ Int. (IF 1.8) Pub Date : 2024-04-15 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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Comparison of Hydrochar and Anthracite as Reducing Agents for Direct Reduction of Hematite ISIJ Int. (IF 1.8) Pub Date : 2024-04-15 Yu-Chiao Lu, Andrey Vladimirovich 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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Isothermal Reduction Kinetics of the Mixture of Iron Carbon Agglomerates and Sinter ISIJ Int. (IF 1.8) Pub Date : 2024-04-15 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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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 : 2024-04-15 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 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 : 2024-04-15 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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RDDPA: Real-time Defect Detection via Pruning Algorithm on Steel Surface ISIJ Int. (IF 1.8) Pub Date : 2024-04-15 Kun Lu, Xuejuan Pan, Chunfeng Mi, Wenyan Wang, Jun Zhang, Peng Chen, Bing Wang
Real-time object detectors deployed on general-purpose graphics processing units (GPUs) or embedded devices allow their mass usage in industrial applications at an affordable cost. However, existing state-of-the-art object detectors are difficult to meet the requirements of high accuracy and low inference latency simultaneously in industrial applications on general-purpose devices. In this work, we
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Assessing the Banding Degree of Martensite in the Bainite Matrix through EPMA ISIJ Int. (IF 1.8) Pub Date : 2024-04-15 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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Efficient Finite Element Simulation of Cold Rolled Strip Coiling Process Considering Additional Contact Deformation between Layers ISIJ Int. (IF 1.8) Pub Date : 2024-04-15 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 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 : 2024-04-15 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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Hydrogen Trapping and Precipitation of Alloy Carbides in Molybdenum Added Steels and Vanadium Added Steels ISIJ Int. (IF 1.8) Pub Date : 2024-04-15 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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Dependence of Mechanical Properties and Deformation Behavior of TRIP-FeMnCoCrAl Dual-phase High-entropy Alloy on Grain Size and Strain Rate ISIJ Int. (IF 1.8) Pub Date : 2024-04-15 Jie Li, Bo Zhang, Lichong Niu, Minghe Zhang, Yunli Feng
Fe50Mn30Co10Cr10 dual-phase metastable high-entropy alloys (HEAS) have gained significant attention for their outstanding mechanical properties. However, limited research has explored the relationship between grain size and strain rate sensitivity (SRS) in dual-phase HEAS. Current investigations primarily focus on pure metals and single-phase FCC HEAS. To address this gap, this study examines the impact
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Effect of Rolling and Alloying Elements on the Impact Properties of Hypereutectoid Steels ISIJ Int. (IF 1.8) Pub Date : 2024-04-15 Toko Tokunaga, Yoritoshi Minamino, Koji Yamamoto, Toshiyuki Sugimoto, Koji Hagihara
In this study, to develop steel with high strength and ductility, steels are designed based on JIS-SUJ2 hypereutectoid steel by controlling the contents of the alloying elements Cr and Mn. The steels are subjected to two types of specially designed heat treatment, i.e., “grain boundary amelioration (GBA)” treatment, with and without rolling. The effects of the alloy type and rolling on the microstructure
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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 : 2024-04-15 Peng Yao Liu, Jun Guo Li, Guo Peng Li, Meng Jie Tao, Xi Zhang, 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 : 2024-04-15 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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Production of silicon by microwave heating ISIJ Int. (IF 1.8) Pub Date : 2024-04-09 Kazuhiro Nagata, Hiroyuki Horikoshi
Mixed powder of SiO2 and SiC was heated to produce Si in air by irradiating multi-mode microwave at 2.45 GHz using a porous alumina crucible of sintered cement. SiC generated heat inside the mixture. Mullite layer was produced inside of crucible wall. Molten Si was produced at the apparent temperature between 1550°C and 1600°C during 5400s and 6000s. The apparent temperature was much lower than 1778°C
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Development of heat-of-fusion measurement for metals using a closed-type aerodynamic levitator ISIJ Int. (IF 1.8) Pub Date : 2024-04-09 Kanta Kawamoto, Takuya Goto, Hidekazu Kobatake
The heats of fusion of Fe, Ni, and Co were measured using a closed-type aerodynamic levitation method to prevent chemical interactions with the container and oxidation of the samples. The hypercooling limits of these metals were experimentally determined using the correlation between the undercooling temperature and thermal plateau time. The heats of fusion of the metals were obtained as the product
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Interactions between interstitial and substitutional elements of solute diatomic and triatomic clusters in α-Fe from first-principles calculations ISIJ Int. (IF 1.8) Pub Date : 2024-04-06 Tokuteru Uesugi, Shuji Ashino, Yorinobu Takigawa, Kenji Higashi
The carburizing and nitriding, essential surface modification methods for steels, enhance wear, fatigue, and corrosion resistance by forming fine carbides, nitrides, and nanoclusters involving alloy elements. Understanding the interactions between interstitial X (C or N) and substitutional elements M is critical for optimizing these processes and tailoring the material properties to specific applications
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Molecular dynamics of solidification ISIJ Int. (IF 1.8) Pub Date : 2024-04-03 Yasushi Shibuta
Over many years, mesoscale analysis such as the phase-field method has been the mainstream for numerical simulation of solidification. In contrast, our group has taken the initiative in applying molecular dynamics (MD) simulation to various problems in solidification. In this review, recent advances and contributions of MD simulations for solidification are presented. The primary contribution of MD
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Hydrogen Embrittlement Susceptibility of Linear Friction Welded Medium Carbon Steel Joints ISIJ Int. (IF 1.8) Pub Date : 2024-04-03 Riki Toramoto, Takayuki Yamashita, Kohsaku Ushioda, Tomohiko Omura, Hidetoshi Fujii
In this study, linear friction welding is applied to join JIS-S45C medium carbon steel with ferrite and pearlite structures at temperatures above and below the A1 point. Additionally, low-strain-rate tensile tests are conducted both in air and with a cathodic hydrogen charge to evaluate the hydrogen-embrittlement susceptibility of the linear friction-welded joints under both joining conditions. Results
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A New type of Online Accelerated Cooling Equipment for Seamless Steel Pipe and Its Application Experiments ISIJ Int. (IF 1.8) Pub Date : 2024-04-03 Long-jie Tao, Yan-chun Liu
A new type of online accelerated cooling equipment for seamless steel pipe and its application experiments were introduced in the present work. The equipment can simultaneously cool the inner and outer surface of seamless steel pipes. By using online accelerated cooling process, the mechanical properties of the test steel pipe made of Q345B composition meet the requirements of Q460E steel grade index
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Influence of ferrosilicon addition on silicon-oxygen equilibria in high-silicon steels ISIJ Int. (IF 1.8) Pub Date : 2024-03-28 Sanjay Pindar, Manish M. Pande
The role of impurities introduced to the steel melt through ferrosilicon addition is of considerable importance in determining the steel cleanness of Si-killed, Si-alloyed steel grades. The silicon requirement is often met with FeSi addition at the industrial scale. In the present study, a detailed investigation of commercial purity ferrosilicon (FeSi) alloy has been conducted to assess its impurity
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Comparison between the Lüders and Portevin–Le Chatelier bands in the low-strain-rate tensile testing of ultralow-carbon ferritic steel ISIJ Int. (IF 1.8) Pub Date : 2024-03-28 Eibun Kyo, Seung-Yong Lee, Ryota Nagashima, Nobuo Nakada, Fusae Shiimori, Nobusuke Kariya, Shinjiro Kaneko
In ferritic steels, solute carbon (C) causes two types of discontinuous stress fluctuations that are accompanied by local deformation bands in the stress–strain curves. One is the yield drop with the Lüders band at yielding, and the other is the serrated flow stress with Portevin–Le Chatelier (PLC) bands during the strain hardening stage, that is, the PLC effect. Lüders band and PLC bands can be explained
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Effect of Paint Baking Treatment on Mechanical Properties of Resistance Spot Welded Q&P 980 Steel ISIJ Int. (IF 1.8) Pub Date : 2024-03-22 Dileep Chandran Ramachandran, Adib Salandari-Rabori, Abdelbaset R. H. Midawi, Andrew Macwan, Elliot Biro
This study investigates the impact of paint baking on the macro and micro-mechanical properties of resistance spot welds in quenched and partitioned 980 steels. It is observed that paint baking enhances both peak load and energy absorption during cross-tension tests, as indicated by load-displacement curves. Four different regions were identified from the load-displacement curves after paint baking
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Burden Particle Contour Extraction from Digital Elevation Model of Blast Furnace Rough Surface ISIJ Int. (IF 1.8) Pub Date : 2024-03-19 Jiuzhou Tian, Akira Tanaka, Di Gao, Qingwen Hou, Xianzhong Chen
This paper reports new research progress on characterizing the burden surface particles of the blast furnace. An algorithm is proposed to extract the contour of the particles on the burden surfaces from their digital elevation models. The statistical distributions of particle size corresponding to the coke and sintered ore burden surfaces are counted from the extraction results of the particle contours
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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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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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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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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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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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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