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Metals, Volume 13, Issue 2 (February 2023) – 259 articles

Cover Story (view full-size image): The precipitation of a Cr- and Mo-rich σ phase in super austenitic stainless steel (SASS) seriously affects their thermoplasticity and corrosion resistance. A new air-cooling and low-temperature diffusion treatment method was adopted, its purpose being to inhibit these precipitates. Ce inhibited the nucleation of the precipitates. B induced the formation of Mo-rich precipitates and precipitates containing B and Mo; the B-containing precipitates were serrated. The formation of B-containing serrated precipitates diminished the Cr-depleted zone near the grain boundary. The addition of B and Ce could lead to a significant improvement in the corrosion resistance of S31254 SASS. View this paper
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18 pages, 9116 KiB  
Article
Quantification of Mesoscale Deformation-Induced Surface Roughness in α-Titanium
by Varvara Romanova, Evgeniya Emelianova, Maxim Pisarev, Olga Zinovieva and Ruslan Balokhonov
Metals 2023, 13(2), 440; https://doi.org/10.3390/met13020440 - 20 Feb 2023
Cited by 2 | Viewed by 1384
Abstract
The phenomenon of mesoscale deformation-induced surface roughening in titanium polycrystals is examined experimentally and numerically. The evolution of the surface morphology under uniaxial tension is analyzed in terms of the standard and ad hoc roughness parameters and the fractal dimension. The statistical estimates [...] Read more.
The phenomenon of mesoscale deformation-induced surface roughening in titanium polycrystals is examined experimentally and numerically. The evolution of the surface morphology under uniaxial tension is analyzed in terms of the standard and ad hoc roughness parameters and the fractal dimension. The statistical estimates are compared to the grain-scale stress-strain fields in order to reveal an interrelation between the in-plane plastic strains and out-of-plane surface displacements. A strong correlation with a determination coefficient of 0.99 is revealed between the dimensionless roughness parameter Rd and the corresponding in-plane plastic strain. The standard roughness parameters Ra and RRMS are shown to correlate linearly with the in-plane strains, but only for moderate tensile deformation, which is due to filtering out low-frequency components in the surface profiles. The fractal dimension DF changes with the subsection strains in a sawtooth fashion, with an abrupt drop in the neck region. The descent portions of the DF dependences are supposedly related to the appearance of low-frequency components in the structure of the surface profiles. Full article
(This article belongs to the Special Issue Fatigue Behavior and Crack Mechanism of Metals and Alloys)
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11 pages, 531 KiB  
Article
Modeling Analysis of Heavy Metal Evaluation in Complex Geological Soil Based on Nemerow Index Method
by Jing Wei, Xiaogang Zheng and Jintong Liu
Metals 2023, 13(2), 439; https://doi.org/10.3390/met13020439 - 20 Feb 2023
Cited by 7 | Viewed by 1561
Abstract
To accurately understand soil environmental quality and improve the problem of the traditional method, which is that it has a single evaluation factor and cannot reflect the overall condition of the soil, a complex geological soil heavy metal evaluation modeling method based on [...] Read more.
To accurately understand soil environmental quality and improve the problem of the traditional method, which is that it has a single evaluation factor and cannot reflect the overall condition of the soil, a complex geological soil heavy metal evaluation modeling method based on the Nemerow index method is proposed. Index evaluation methods, ArcGIS technology, and a human health risk assessment were carried out to obtain the spatial distribution of heavy metals in the soil and the current status of pollution accumulation. The comprehensive pollution index (CPI) method, geo-accumulation index (GAI) method, and potential ecological hazard (PEH) index were adopted to analyze the pollution degree of soil heavy metals. On this basis, the Nemerow index method was used to establish a complex geological soil heavy metal evaluation model, and the standard Nemerow index was calculated to complete the evaluation of heavy metal pollution in complex geological soils. The research results showed that this method could make the evaluation factors obtain reasonable scores and obtain more reasonable soil evaluation results. Full article
(This article belongs to the Topic Properties of the Corroding Interface)
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20 pages, 5192 KiB  
Article
A Novel Two-Stage Method of Co-Leaching of Manganese–Silver Ore and Silver-Bearing Pyrite Based on Successive Chemical and Bio Treatments: Optimization and Mechanism Study
by Jianzhi Sun, He Shang, Qidong Zhang, Xue Liu, Liulu Cai, Jiankang Wen and Han Yang
Metals 2023, 13(2), 438; https://doi.org/10.3390/met13020438 - 20 Feb 2023
Cited by 2 | Viewed by 1476
Abstract
In this work, bio-hydrometallurgy technology was employed and a novel two-stage method based on successive chemical and bio treatments was proposed to collaboratively utilize manganese–silver ore and silver-bearing pyrite. In the optimization research of the chemical leaching stage, the sensitive factors for the [...] Read more.
In this work, bio-hydrometallurgy technology was employed and a novel two-stage method based on successive chemical and bio treatments was proposed to collaboratively utilize manganese–silver ore and silver-bearing pyrite. In the optimization research of the chemical leaching stage, the sensitive factors for the Mn leaching efficiency were screened by Plackett–Burman design, and central compound design was performed to settle the optimized parameters. A mixed strain of bacteria containing Sulfobacillus thermosulfidooxidans, At. caldus and Leptospirillum ferrooxidans was applied in the bioleaching stage. A conventional cyanidation process carried out with the Mn leaching residuals suggested an efficient recovery of Ag. Applying a two-stage method with the optimum conditions, the leaching efficiency of 95.3% (Mn) and 96.3% (Ag) were obtained with 284.94 kg/t silver-bearing pyrite addition and 277.44 kg/t sulfuric acid consumption with a temperature at 77.73 °C and stirring speed at 287.76 rpm. Mineral behaviors were investigated with XRD and SEM/EDS analysis, and it was revealed that the oxidation of sulfur is the crux in reducing the usage of reagents, and the presence of leaching bacteria enhanced the oxidation efficiently. Through optimization and mechanism study, this paper provides an opportunity to co-leach the manganese–silver ore and silver-bearing pyrite process in a more economical and environmental way. Full article
(This article belongs to the Special Issue New Technologies in Leaching and Recovery of Valuable Metals)
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15 pages, 4557 KiB  
Article
A Comprehensive Analysis of Surface Roughness, Vibration, and Acoustic Emissions Based on Machine Learning during Hard Turning of AISI 4140 Steel
by İlhan Asiltürk, Mustafa Kuntoğlu, Rüstem Binali, Harun Akkuş and Emin Salur
Metals 2023, 13(2), 437; https://doi.org/10.3390/met13020437 - 20 Feb 2023
Cited by 6 | Viewed by 1682
Abstract
Industrial materials are materials used in the manufacture of products such as durable machines and equipment. For this reason, industrial materials have importance in many aspects of human life, including social, environmental, and technological elements, and require further attention during the production process. [...] Read more.
Industrial materials are materials used in the manufacture of products such as durable machines and equipment. For this reason, industrial materials have importance in many aspects of human life, including social, environmental, and technological elements, and require further attention during the production process. Optimization and modeling play an important role in achieving better results in machining operations, according to common knowledge. As a widely preferred material in the automotive sector, hardened AISI 4140 is a significant base material for shaft, gear, and bearing parts, thanks to its remarkable features such as hardness and toughness. However, such properties adversely affect the machining performance of this material system, due to vibrations inducing quick tool wear and poor surface quality during cutting operations. The main focus of this study is to determine the effect of parameter levels (three levels of cutting speed, feed, and cutting depth) on vibrations, surface roughness, and acoustic emissions during dry turning operation. A fuzzy inference system-based machine learning approach was utilized to predict the responses. According to the obtained findings, fuzzy logic predicts surface roughness (88%), vibration (86%), and acoustic emission (87%) values with high accuracy. The outcome of this study is expected to make a contribution to the literature showing the impact of turning conditions on the machining characteristics of industrially important materials. Full article
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31 pages, 5869 KiB  
Article
Prediction of Angular Distortion in Gas Metal Arc Welding of Structural Steel Plates Using Artificial Neural Networks
by Kuluthupalayam Maruthavanan Eazhil, Ranganathan Sudhakaran, Elumalai Perumal Venkatesan, Abdul Aabid and Muneer Baig
Metals 2023, 13(2), 436; https://doi.org/10.3390/met13020436 - 20 Feb 2023
Cited by 6 | Viewed by 2456
Abstract
The manufacturing of structures ranging from bridges and machinery to all types of seaborne vehicles to nuclear reactors and space rockets has made considerable use of arc welding technologies. This is as a result of benefits including increased joint efficiency, air and water [...] Read more.
The manufacturing of structures ranging from bridges and machinery to all types of seaborne vehicles to nuclear reactors and space rockets has made considerable use of arc welding technologies. This is as a result of benefits including increased joint efficiency, air and water tightness, no thickness restriction (0.6 to 25 mm), decreased fabrication time and cost, etc. when compared to alternative fabrication methods. Gas metal arc welding (GMAW) is a frequently used welding technology in industries due to its inherent benefits, including deeper penetration, a smooth bead, etc. Local heating and cooling that takes place during the multi-pass welding process causes complicated stresses to develop at the weld zone, which ultimately causes angular distortion in the weldment. Angular distortion is a major flaw that affects the weld’s properties as well as the cracking and misalignment of the welded joints. The issue of angular distortion can be successfully solved by predicting it in relation to certain GMAW process variables. A neural network model was created in this research to predict angular distortion. A fractional factorial approach with 125 runs was used to conduct the exploratory experiments. A neural network model with feed forward and backward propagation was developed using the experimental data. To train the neural network model, the Levenberg–Marquardt method was utilised. The results indicate that the model based on network 4-9-3 is more effective in forecasting angular distortion with time gaps between two, three, and four passes than the other three networks (4-2-3, 4-4-3, 797 and 4-8-3). Prediction accuracy is more than 95 percent. The neural network model developed in this study can be used to manage the welding cycle in structural steel weld plates to achieve the best possible weld quality with the least amount of angular distortion. Full article
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19 pages, 6819 KiB  
Article
Analysis of Lead Smelting Technology in the Early Bronze Age Based on Smelting Slag from the Central Plains of China
by Shuoyang Li, Yanxiang Li, Rong Zhu and Hongyang Wang
Metals 2023, 13(2), 435; https://doi.org/10.3390/met13020435 - 20 Feb 2023
Cited by 2 | Viewed by 1900
Abstract
To explore the source of Pb in Bronze Age artefacts from the Central Plains (Zhongyuan) in China, we investigated non-ferrous minerals from the Qingyuan archaeological site in Yuanqu County near the Zhongtiao Mountains. Fragments of smelting slag from the Erlitou cultural layer were [...] Read more.
To explore the source of Pb in Bronze Age artefacts from the Central Plains (Zhongyuan) in China, we investigated non-ferrous minerals from the Qingyuan archaeological site in Yuanqu County near the Zhongtiao Mountains. Fragments of smelting slag from the Erlitou cultural layer were collected. The smelting slag was investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and lead isotope analysis. The SEM and EDS results confirmed that the slag contained Pb, Pb–As, and Cu–Pb–Sn inclusions and non-metal impurities such as low-Zn spinels. The XRD results signified that the bulk of the slag comprised Fe–Mn–Si phases. The chemical state of Pb was mainly Pb–O with some metallic Pb, as identified by XPS. The theoretical melting point was calculated using FactSage7.1 based on the composition and phase characterisation. The calculated temperature was 1100–1200 °C, which agreed well with the actual melting point of 1114–1354 °C. The slag composition and inclusion phases indicated that Pb–Zn–O ores with Mn and As were added during reduction smelting in Qingyuan. The raw materials of smelting included crude Pb with minor amounts of Cu, As, and Sn. Lead isotope analysis revealed that the lead materials produced in Qingyuan were likely transferred to Yanshi City in the Shang Dynasty. The findings of this study provide significant clues for exploring lead mineral production in the Central Plains during the Early Bronze Age. Full article
(This article belongs to the Special Issue Metals for Art and Cultural Heritage)
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16 pages, 11054 KiB  
Article
Flexural Behavior of Stainless Steel V-Stiffened Lipped Channel Beams
by Shuang-E Huangfu, Zhong Tao, Ji Zhang, Wahab Abdul Ghafar, Zihao Wang, Caifeng Ye and Md Mehedi Hasan
Metals 2023, 13(2), 434; https://doi.org/10.3390/met13020434 - 20 Feb 2023
Cited by 1 | Viewed by 1134
Abstract
Six groups of austenitic 022Cr19Ni10 stainless steel bending specimens with three types of cross-sectional forms were used to study the impact of V-stiffeners on the failure mode and flexural behavior of stainless steel lipped channel beams. These cross-sectional forms included V-stiffeners in the [...] Read more.
Six groups of austenitic 022Cr19Ni10 stainless steel bending specimens with three types of cross-sectional forms were used to study the impact of V-stiffeners on the failure mode and flexural behavior of stainless steel lipped channel beams. These cross-sectional forms included V-stiffeners in the web compression zone at 1/3 height near the compressed flange and no V-stiffeners on the flange, V-stiffeners in the web compression zone at 1/3 height near the compressed flange and V-stiffeners in the middle of the compressed flange, and V-stiffeners on the web at 1/2 height and V-stiffeners in the middle of the compressed and tensioned flange. The findings show that the specimens without a V-stiffener on the flange and with a V-stiffener in the web compression zone at 1/3 height near the compressed flange have a lower ultimate bearing capacity as a result of local–distortional interaction buckling. The test specimen’s flexural bearing capacity will rise with an increase in web height under the same stiffening form and other fixed cross-sectional parameters. Furthermore, the additional V-stiffeners in the middle of the flange effectively lower the width-to-thickness ratio of the stainless steel specimen with a flange that has been V-stiffened, thus increasing the specimen’s bending bearing capacity by 13% and emphasizing the distortional buckling issue. Buckling first manifests in the compression flange and is caused by the stress evolution on the web of the bending specimen, which is constrained by the V-stiffeners. The specimen’s capacity to withstand bending loads can be improved more successfully through the use of V-stiffeners in the web compression zone at 1/3 height close to the compressed flange and V-stiffeners in the middle of the compressed flange. For the test data, a finite element simulation was established, and the results are generally consistent with the test results. Full article
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17 pages, 3113 KiB  
Article
Reduction of Residual Stresses in Cold Drawn Pearlitic Steel by a Soft Secondary Wire Diameter Reduction
by Jesús Toribio and Miguel Lorenzo
Metals 2023, 13(2), 433; https://doi.org/10.3390/met13020433 - 20 Feb 2023
Cited by 3 | Viewed by 1221
Abstract
In this paper, the effects of the skin pass technique on the residual stress and plastic strain fields generated in cold drawn pearlitic steel wires are analyzed. The aim is to find out the optimal conditions to be used in the design of [...] Read more.
In this paper, the effects of the skin pass technique on the residual stress and plastic strain fields generated in cold drawn pearlitic steel wires are analyzed. The aim is to find out the optimal conditions to be used in the design of a manufacturing process for obtaining more reliable structural components in terms of the main cause of failure: the hydrogen embrittlement (HE). To achieve this goal, diverse numerical simulations were performed by using finite elements (FE) and considering, on one hand, the first step of a real cold drawing chain, using (i) a conventional drawing die and (ii) modified drawing dies with different soft diameter reductions, and, on the other hand, numerical simulations by FE of the hydrogen diffusion assisted by stress and strain states to estimate the hydrogen distributions. Obtained results revealed the secondary reduction degree as a key parameter in the die design for reducing the drawing-induced residual stress. According to the results, low values of the reduction ratio cause radial distributions of residual stress with significant reductions at both the wire core and at the wire surface. In addition, the hydrogen accumulation at the prospective damage zone (near the wire surface) given by FE simulations is lower in the wires drawn with modified drawing dies including a skin pass zone. Full article
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13 pages, 8504 KiB  
Article
Preparation and Microstructure of Multi-Component High Entropy Alloy Powders Fabricated by Gas Atomization Method
by Zhiqiang Ren, Sheng Zhu, Xiaoming Wang, Yang Zhao, Guofeng Han, Kebing Zhou, Wenyu Wang and Gen Tian
Metals 2023, 13(2), 432; https://doi.org/10.3390/met13020432 - 20 Feb 2023
Cited by 4 | Viewed by 1592
Abstract
As an attractive high-entropy alloy, AlCrCoNiCu high-entropy alloy has excellent corrosion resistance, wear resistance, and anti-bacterial capabilities, and is considered to be a potential substitute material for marine and nuclear industry materials with great potential. One key to further optimizing the performance of [...] Read more.
As an attractive high-entropy alloy, AlCrCoNiCu high-entropy alloy has excellent corrosion resistance, wear resistance, and anti-bacterial capabilities, and is considered to be a potential substitute material for marine and nuclear industry materials with great potential. One key to further optimizing the performance of high entropy alloy was to prepare high entropy alloy powder materials with uniform composition, good flow-ability, and stable performance. In this work, the AlCrCoNiCu high entropy alloy powder was prepared by the gas atomization method. The results indicated that the powder was spherical in shape, homogeneous in composition, and composed of a face-center cubic (FCC) phase. After adding Fe and Mn elements, FCC and body-center cubic (BCC) phases appeared and the particle size of the powder was mainly located at 10–50 μm. Furthermore, the larger the particle size was, the more obvious the surface roughness was. With the decreasing powder size, its shape became relatively regular, and the surface roughness decreased. This work provided an experimental and theoretical reference for preparing high-performance single-phase and multi-phase high entropy alloy spherical powders. Full article
(This article belongs to the Special Issue Amorphous and High-Entropy Alloy Coatings)
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15 pages, 7375 KiB  
Article
Effect of TiO2 Addition on the Melting Behaviors of CaO-SiO2-30%Al2O3-5%MgO System Refining Slags
by Xiaomeng Zhang, Ziwen Yan, Zhiyin Deng and Miaoyong Zhu
Metals 2023, 13(2), 431; https://doi.org/10.3390/met13020431 - 20 Feb 2023
Cited by 3 | Viewed by 1537
Abstract
To improve the yield of titanium alloy, a certain amount of TiO2 can be added to the refining slag system of Ti-bearing steel grades. With the aim of understanding the effect of TiO2 addition on the melting behaviors of CaO-SiO2 [...] Read more.
To improve the yield of titanium alloy, a certain amount of TiO2 can be added to the refining slag system of Ti-bearing steel grades. With the aim of understanding the effect of TiO2 addition on the melting behaviors of CaO-SiO2-30%Al2O3-5%MgO refining slags, the melting points of the slags and the phases in the slags are herein studied at different temperatures in the laboratory. It is found that with the increase in TiO2 content (0~10%) in slag, the melting point of the slags drops first, and then rises. The effect of slag basicity (R = w(CaO)/w(SiO2), 2~10) shows a similar tendency. The TiO2 content and slag basicity evidently affect the precipitated phases in the slags at a lower temperature (e.g., 1310 °C). With the increase in basicity, the liquid areal fraction increases first, and then decreases. Moreover, the CaO-TiOx-Al2O3 phase (CTA) and its TiOx content show a declining trend at 1310 °C. When R = 10, large amounts of solid calcium aluminates are precipitated. With TiO2 addition in the slags, the TiOx contents in both liquid and CTA phases increase. Excessive TiO2 addition (e.g., 10%) leads to the large precipitation of CTA, as well. To improve the melting properties of the slag and the yield of Ti alloys during the refinement of Ti-bearing steel grades, a small TiO2 addition (e.g., 5%) may be considered. Full article
(This article belongs to the Special Issue Non-metallic Inclusions in Steelmaking)
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19 pages, 6095 KiB  
Article
Tribo-Mechanical Behavior of Films and Modified Layers Produced by Cathodic Cage and Glow Discharge Plasma Nitriding Techniques
by Bruna C. E. Schibicheski Kurelo, Gelson Biscaia De Souza, Silvio Luiz Rutz Da Silva, Carlos Maurício Lepienski, Clodomiro Alves Júnior, Rafael Fillus Chuproski and Giuseppe Pintaúde
Metals 2023, 13(2), 430; https://doi.org/10.3390/met13020430 - 19 Feb 2023
Cited by 1 | Viewed by 1339
Abstract
Two surface modification techniques, the glow discharge plasma nitriding (GDPN) and the cathodic cage plasma nitriding (CCPN), were compared regarding the mechanical and tribological behavior of layers produced on AISI 316 stainless-steel surfaces. The analyses were carried out at the micro/nanoscale using nanoindentation [...] Read more.
Two surface modification techniques, the glow discharge plasma nitriding (GDPN) and the cathodic cage plasma nitriding (CCPN), were compared regarding the mechanical and tribological behavior of layers produced on AISI 316 stainless-steel surfaces. The analyses were carried out at the micro/nanoscale using nanoindentation and nanoscratch tests. The nitriding temperature (°C) and time (h) parameters were 350/6, 400/6, and 450/6. Morphology, structure, and microstructure were evaluated by X-ray diffraction, scanning electron and optical interferometry microscopies, and energy-dispersive X-ray spectroscopy. GDPN results in stratified modified surfaces, solidly integrated with the substrate, with a temperature-dependent composition comprising nitrides (γ’-Fe4N, ε-Fe2+xN, CrN) and N-solid solution (γN phase). The latter prevails for the low treatment temperatures. Hardness increases from ~2.5 GPa (bare surface) to ~15.5 GPa (450 °C). The scratch resistance of the GDPN-modified surfaces presents a strong correlation with the layer composition and thickness, with the result that the 400 °C condition exhibits the highest standards against microwear. In contrast, CCPN results in well-defined dual-layers for any of the temperatures. A top 0.3–0.8 µm-thick nitride film (most ε-phase), brittle and easily removable under scratch with loads as low as 63 mN, covers a γN-rich case with hardness of 10 GPa. The thickness of the underneath CCPN layer produced at 450 °C is similar to that from GDPN at 400 °C (3 µm); on the other hand, the average roughness is much lower, comparable to the reference surface (Ra ~10 nm), while the layer formation involves no chromium depletion. Moreover, edge effects are absent across the entire sample´s surface. In conclusion, among the studied conditions, the GDPN 400 °C disclosed the best tribo-mechanical performance, whereas CCPN resulted in superior surface finishing for application purposes. Full article
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24 pages, 6148 KiB  
Article
Effect of Heat Treatment on the Electrochemical Behavior of AA2055 and AA2024 Alloys for Aeronautical Applications
by Heriberto Rivera-Cerezo, Citlalli Gaona-Tiburcio, Jose Cabral-Miramontes, Raúl Germán Bautista-Margulis, Demetrio Nieves-Mendoza, Erick Maldonado-Bandala, Francisco Estupiñán-López and Facundo Almeraya-Calderón
Metals 2023, 13(2), 429; https://doi.org/10.3390/met13020429 - 19 Feb 2023
Cited by 4 | Viewed by 1306
Abstract
Since their development, third-generation aluminum–lithium alloys have been used in aeronautical and other applications due to their good properties, replacing conventional Al-Cu and Al-Zn alloys and resulting in an increase in payload and fuel efficiency. The aim of this work was to investigate [...] Read more.
Since their development, third-generation aluminum–lithium alloys have been used in aeronautical and other applications due to their good properties, replacing conventional Al-Cu and Al-Zn alloys and resulting in an increase in payload and fuel efficiency. The aim of this work was to investigate the influence of different heat treatments on the electrochemical corrosion behavior of the alloys AA2055 and AA2024 in the presence of three different electrolytes at room temperature, using an electrochemical noise (EN) technique in accordance with the ASTM-G199 standard. In the time domain, the polynomial method was employed to obtain the noise resistance (Rn), the localization index (IL), skewness, and kurtosis, and in the frequency domain, employing power spectral density analysis (PSD). The microstructure and mechanical properties of the alloys were characterized using scanning electron microscopy (SEM) and the Vickers microhardness test (HV). The results demonstrated better mechanical properties of the AA2055 alloy, which had a Vickers hardness of 77, 174, and 199 in the heat treatments T0, T6, and T8, respectively. An electrochemical noise resistance (Rn) of 2.72 × 105 Ω·cm2 was obtained in the AA2055 T8 alloy evaluated in a NaCl solution, while the lowest Rn resistance of 2.87 × 101 Ω·cm2 occurred in the AA2024 T8 alloy, which was evaluated in a HCl solution. The highest electrochemical noise resistance (Rn) was obtained in the AA2055 alloys, which had received the T6 and T8 heat treatments in the three solutions. Full article
(This article belongs to the Section Corrosion and Protection)
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14 pages, 15704 KiB  
Article
Selective Laser Melting of (Fe-Si-B)/Cu Composite: Structure and Magnetic Properties Study
by Danil Erutin, Anatoly Popovich and Vadim Sufiiarov
Metals 2023, 13(2), 428; https://doi.org/10.3390/met13020428 - 19 Feb 2023
Cited by 1 | Viewed by 1108
Abstract
A mixture of original 1CP powder and 10 wt.% of pure Cu-powder was prepared and 1CP-Cu composite samples were obtained by selective laser melting using different process parameters. Comparison of pure 1CP and composite samples showed that addition of Cu halved the porosity [...] Read more.
A mixture of original 1CP powder and 10 wt.% of pure Cu-powder was prepared and 1CP-Cu composite samples were obtained by selective laser melting using different process parameters. Comparison of pure 1CP and composite samples showed that addition of Cu halved the porosity percentage of the obtained material. Distribution of Cu-phase in 1CP-matrix can be recognized as uniform in all the samples. X-ray diffraction of samples showed the presence of α-Fe solid solution, iron boride Fe2B, and crystal Cu. Scanning electron microscopy analysis also allowed to discover ordered solid solution Fe3Si in samples microstructure. Differential scanning calorimetry data showed that composite sample contains amorphous phase as opposed to pure 1CP sample manufactured using the same process parameters. Magnetic properties of samples were studied, and it was found that addition of 10 wt.% of Cu allowed to reduce magnetic field energy losses by approximately four times. Full article
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11 pages, 5568 KiB  
Article
Evaluation of Mechanical Properties of Different Casing Drilling Steels
by Xiaoyu He, Min Zhang, Tianhan Xu, Longyu Lei and Yi Li
Metals 2023, 13(2), 427; https://doi.org/10.3390/met13020427 - 19 Feb 2023
Viewed by 1239
Abstract
An investigation into the mechanical properties of K55, N80, and P110 steels commonly used for casing drilling was carried out together with microstructural and fractographic analysis. The results show that P110 steel consisted of almost fully tempered martensite and exhibited a synergy combination [...] Read more.
An investigation into the mechanical properties of K55, N80, and P110 steels commonly used for casing drilling was carried out together with microstructural and fractographic analysis. The results show that P110 steel consisted of almost fully tempered martensite and exhibited a synergy combination of static tensile, dynamic impact, and fatigue crack propagation properties among the three steels, possessing a higher fatigue limit and deeper crack tolerance before failure occurred. The K55 steel consisted of the pearlite and network structure of ferrite and possessed a high strain hardening exponent and low impact property, which led to the more suitable application under incidental large overload and temperature change, but it was unsuitable under the condition of higher impact force. The properties of N80 steel were moderate, and its fatigue property was higher than that of K55 and lower than that of P110; its incidental overload resistance was also higher than that of P110. The casing drilling steel can be selected according to the environment. Full article
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16 pages, 6107 KiB  
Article
Study on Denitration Performance of Mn-Ce/TiO2 Low-Temperature SCR Catalyst
by Ran Liu, Yanting Liu, Yanjia Gao and Qian Hu
Metals 2023, 13(2), 426; https://doi.org/10.3390/met13020426 - 18 Feb 2023
Cited by 3 | Viewed by 1433
Abstract
Low sintering flue gas temperatures and large temperature fluctuations require the development of low-temperature and efficient SCR (selective catalytic reduction) catalysts suitable for the sintering process. It has been shown that modified Mn-Ce/TiO2 catalysts have good denitration capability and have potential commercial [...] Read more.
Low sintering flue gas temperatures and large temperature fluctuations require the development of low-temperature and efficient SCR (selective catalytic reduction) catalysts suitable for the sintering process. It has been shown that modified Mn-Ce/TiO2 catalysts have good denitration capability and have potential commercial use. In this experiment, TiO2-loaded Mn and Ce SCR catalysts were prepared using the impregnation method, and a series of characterizations of the samples were carried out to illustrate the effect of the active material on the denitration efficiency. The kinetic analysis provides theoretical as well as data support for the subsequent optimization of the SCR catalysts. The results show that the denitration efficiency of the catalysts can reach 93.86% when the Mn content is 10% and the Ce content is 3%. The doping of active substances can increase the specific surface area, total pore volume and average aperture of the catalysts and improve the adsorption capacity of the catalysts. Full article
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18 pages, 8334 KiB  
Article
Research on Simulation and Optimization of Traveling Induction Heating Process for Welding Deformation Rectification in High Strength Steel Sheet
by Yulong Feng, Yujun Liu, Ji Wang and Rui Li
Metals 2023, 13(2), 425; https://doi.org/10.3390/met13020425 - 18 Feb 2023
Viewed by 1334
Abstract
To observe the evolution mechanism of physical fields in the welding deformation rectification process by a traveling induction heating, research on simulation models of welding—induction heating continuous process were carried out. High-strength steel plates were selected for welding deformation experiment and induction heating [...] Read more.
To observe the evolution mechanism of physical fields in the welding deformation rectification process by a traveling induction heating, research on simulation models of welding—induction heating continuous process were carried out. High-strength steel plates were selected for welding deformation experiment and induction heating rectification experiment in turn, and the stress field and strain field distribution after various processes were measured and recorded. Then, according to the construction process, an integrated model of welding-induction heating based on moving mesh method was analyzed and established by Ansys FE software, moreover, another progressive integrated model established based on the re-defined element attributes method was studied, and the calculation accuracy of these models were compared as well as the characteristics were analyzed. The research results show that these two integrated models can accurately reflect the evolution law of each physical field in the process of welding and induction heating, and the re-defined element attributes method is more suitable for the research of welding deformation and induction heating rectification process. Full article
(This article belongs to the Special Issue Numerical Simulation of Metals Welding Process)
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22 pages, 2352 KiB  
Review
Current Status and Challenges of Powder Bed Fusion-Based Metal Additive Manufacturing: Literature Review
by Naol Dessalegn Dejene and Hirpa G. Lemu
Metals 2023, 13(2), 424; https://doi.org/10.3390/met13020424 - 18 Feb 2023
Cited by 17 | Viewed by 6242
Abstract
Powder bed fusion (PBF) is recognized as one of the most common additive manufacturing technologies because of its attractive capability of fabricating complex geometries using many possible materials. However, the quality and reliability of parts produced by this technology are observed to be [...] Read more.
Powder bed fusion (PBF) is recognized as one of the most common additive manufacturing technologies because of its attractive capability of fabricating complex geometries using many possible materials. However, the quality and reliability of parts produced by this technology are observed to be crucial aspects. In addition, the challenges of PBF-produced parts are hot issues among stakeholders because parts are still insufficient to meet the strict requirements of high-tech industries. This paper discusses the present state of the art in PBF and technological challenges, with a focus on selective laser melting (SLM). The review work focuses mainly on articles that emphasize the status and challenges of PBF metal-based AM, and the study is primarily limited to open-access sources, with special attention given to the process parameters and flaws as a determining factor for printed part quality and reliability. Moreover, the common defects due to an unstrained process parameter of SLM and those needed to monitor and sustain the quality and reliability of components are encompassed. From this review work, it has been observed that there are several factors, such as laser parameters, powder characteristics, material properties of powder and the printing chamber environments, that affect the SLM printing process and the mechanical properties of printed parts. It is also concluded that the SLM process is not only expensive and slow compared with conventional manufacturing processes, but it also suffers from key drawbacks, such as its reliability and quality in terms of dimensional accuracy, mechanical strength and surface roughness. Full article
(This article belongs to the Special Issue 3D Printing of Metal)
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12 pages, 2010 KiB  
Article
The Effect of Welding Mode Parameters on the Operational Properties of Flexible Compensating Elements Made of Austenitic Stainless Steels
by Vitaliy Petrovich Ivanov, Elena Vladimirovna Lavrova, Fedor Viktorovich Morgay, Dmitry Pavlovich Ilyashenko and Viktoria Yuryevna Ivashchenko
Metals 2023, 13(2), 423; https://doi.org/10.3390/met13020423 - 17 Feb 2023
Cited by 3 | Viewed by 1553
Abstract
The paper investigates the effect of welding mode parameters on the uniformity of the deformation capacity of AISI 316 austenitic steel samples, namely, the influence of the welding current and purging gas consumption on the samples’ ability to perceive the force of cold [...] Read more.
The paper investigates the effect of welding mode parameters on the uniformity of the deformation capacity of AISI 316 austenitic steel samples, namely, the influence of the welding current and purging gas consumption on the samples’ ability to perceive the force of cold cupping. Punch diameters of 3 and 8 mm were employed for the Erikson test to establish the dependence of the purge gas flow rate on the depth of the hole before the formation of cracks. The conducted metallographic studies confirmed an increase in the homogeneity of the dendritic structure in the weld zone due to the redistribution of heat input, as well as the absence of uneven grains and a decrease in the spread of grain sizes, which were in the range of 0.068–0.045 mm. The study resulted in determining the optimal range of technological parameters for the manufacture of flexible expansion elements to ensure their high operational properties. Full article
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16 pages, 3714 KiB  
Article
Elemental Fluctuation in Gd3Al2Ga3O12:Ce Crystals Imposed by Li+ and Mg2+ Co-Doping: The Impact on Defects, Luminescence, and Scintillation Properties
by Karol Bartosiewicz
Metals 2023, 13(2), 422; https://doi.org/10.3390/met13020422 - 17 Feb 2023
Cited by 2 | Viewed by 1114
Abstract
This research revealed the response of Ga and Al sublattices to the incorporation of mismatching substituents in Gd3Al2Ga3O12:Ce single crystals. Incompatible in size and charge, Li+ and Mg2+ substituents violated configurational entropy. This [...] Read more.
This research revealed the response of Ga and Al sublattices to the incorporation of mismatching substituents in Gd3Al2Ga3O12:Ce single crystals. Incompatible in size and charge, Li+ and Mg2+ substituents violated configurational entropy. This led to lattice distortion and triggered structural rearrangements. The radial fluctuation of the Ga and Al elements was proven by multi-elemental energy-dispersive X-ray spectroscopy mapping and elemental composition analysis. Further evidence was observed by the shift of the exciton creation energy toward higher energy in the vacuum ultraviolet excitation spectra recorded with synchrotron radiation. In the Li+ and Mg2+ co-doped samples, the crystal core was depleted with Ga atoms and enriched with Al elements. The crystal rim showed the opposite behavior. The change in thermoluminescence peak positions revealed a different mechanism for the formation of localized traps. As a result, Li+ co-doping slightly improved the light yield value, but at the same time decelerated the scintillation decay time. On the contrary, Mg2+ co-doping markedly diminished scintillation parameters. Full article
(This article belongs to the Section Crystallography and Applications of Metallic Materials)
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19 pages, 18566 KiB  
Article
Dissolution of Microalloying Elements in a Ladle Metallurgy Furnace
by Ogochukwu Queeneth Duruiheme, Xipeng Guo, Nicholas Walla and Chenn Zhou
Metals 2023, 13(2), 421; https://doi.org/10.3390/met13020421 - 17 Feb 2023
Cited by 1 | Viewed by 1527
Abstract
Industrial fusion of microalloying elements in steelmaking is imperative in defining and optimizing certain steel properties due to their strengthening and significant grain refinements effects at minute quantities. Copper, vanadium, and columbium are explored in this investigation to monitor their respective dissolution processes [...] Read more.
Industrial fusion of microalloying elements in steelmaking is imperative in defining and optimizing certain steel properties due to their strengthening and significant grain refinements effects at minute quantities. Copper, vanadium, and columbium are explored in this investigation to monitor their respective dissolution processes in a ladle metallurgy furnace (LMF), with concise parametric studies on effects of number of plugs and variations in argon gas flow rates for stirring. To track particle disintegration in the molten bath inside, intricate numerical processing was carried out with the use of mathematical models and to simulate the mixing process; turbulent multiphase computational fluid dynamics (CFD) models were combined with a user-defined function. The numerical findings highlight the connection between mixing time and gas blowing since the quantity of stirring plugs employed and the gas flow rates directly affect mixing effectiveness. The amount of particles to be injected and their total injection time were validated using industrial measurement; an average difference of 9.9% was achieved. In order to establish the need for an exceptionally high flow rate and inevitably reduce resource waste, extreme charging of flow rates for gas stirring were compared to lesser gas flow rates in both dual- and single-plug ladles. The results show that a single-plug ladle with a flow rate of 0.85 m3/min and a dual-plug ladle with a total flow rate of 1.13 m3/min have the same mixing time of 5.6 min, which was the shortest among all scenarios. Full article
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17 pages, 8024 KiB  
Article
High-Throughput Investigation of Multiscale Deformation Mechanism in Additively Manufactured Ni Superalloy
by Abhijeet Dhal, Priyanka Agrawal, Ravi Sankar Haridas, Supreeth Gaddam, Aishani Sharma, Digvijay Parganiha, Rajiv S. Mishra, Hirotsugu Kawanaka, Shinji Matsushita, Yusuke Yasuda, Seung Hwan C. Park and Wei Yuan
Metals 2023, 13(2), 420; https://doi.org/10.3390/met13020420 - 17 Feb 2023
Cited by 1 | Viewed by 1697
Abstract
In this paper, Inconel 718 (IN718) superalloy was processed by laser powder-bed fusion additive manufacturing (L-PBFAM), followed by heat treatment. High-resolution nanoindentation was used to investigate the complex deformation mechanisms that occurred at various length scales in both conditions. The nanoindentation elastoplastic maps [...] Read more.
In this paper, Inconel 718 (IN718) superalloy was processed by laser powder-bed fusion additive manufacturing (L-PBFAM), followed by heat treatment. High-resolution nanoindentation was used to investigate the complex deformation mechanisms that occurred at various length scales in both conditions. The nanoindentation elastoplastic maps show a strong crystal orientation dependency of modulus and hardness, which is attributed to the high mechanical anisotropy of IN718. The hardness map effectively resolves complex microscale strength variation imparted due to the hierarchical heat distribution associated with the thermal cycles of L-PBFAM. The disproportionately high hardening effect of Nb, Mo-rich chemical segregations and Laves phases in dendritic structures is also observed. The heat treatment resulted in a 67% increase in yield strength (from 731 MPa in the L-PBFAM condition to 1217 MPa in the heat-treated condition) due to the activation of multiple precipitation-strengthening mechanisms. The nanoindentation mapping of a heat-treated sample delineates the orientation-dependent hardness distribution, which apart from high mechanical anisotropy of the alloy, is also contributed to by a high degree of coherency strengthening of the D022 γ″-precipitates oriented parallel to the <001> crystal plane of the γ-matrix. The mean hardness of the sample increased from 13.3 GPa to 14.8 GPa after heat treatment. Evidence of extensive deformation of twin networks and dislocation cells was revealed by transmission electron microscopy of the deformed region under the nanoindentation tip. Full article
(This article belongs to the Special Issue Deformation of Metals and Alloys: Theory, Simulations and Experiments)
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17 pages, 1525 KiB  
Article
Research on Sinter Quality Prediction System Based on Granger Causality Analysis and Stacking Integration Algorithm
by Xin Li, Xiaojie Liu, Hongyang Li, Ran Liu, Zhifeng Zhang, Hongwei Li, Qing Lyu and Liangyixin Wen
Metals 2023, 13(2), 419; https://doi.org/10.3390/met13020419 - 17 Feb 2023
Cited by 2 | Viewed by 1221
Abstract
Sinter ore quality directly affects the stability of blast furnace production. In terms of both physical and chemical properties, the main indicators of sinter quality are the TFe content, alkalinity, and drum index. By analyzing the massive historical data on the sinter production [...] Read more.
Sinter ore quality directly affects the stability of blast furnace production. In terms of both physical and chemical properties, the main indicators of sinter quality are the TFe content, alkalinity, and drum index. By analyzing the massive historical data on the sinter production of a steel company, this study proposes a sinter quality prediction system based on Granger causality analysis and a stacking integration algorithm. First, based on real historical data of sintering production in steel enterprises (including coal gas pressure, ignition temperature, combustion air pressure, etc.), data preprocessing of raw data was carried out using a combination of feature engineering and the sintering process. Second, Pearson correlation analysis, Spearman correlation analysis, and Granger causality analysis were used to screen out the characteristic parameters with a strong influence on the target variable of sinter quality (drum Index, TFe, alkalinity). Third, a prediction model for sinter quality parameters was developed using a stacking integration algorithm pair for training. Finally, a program development tool was used to realize the establishment and online operation of a sinter ore quality prediction system. The test results showed that the predicted goodness of fit of the model for the TFe content, alkalinity (R), and drum index were 0.942, 0.958, and 0.987, respectively, and the model calculation time met the actual production requirements. By establishing a suitable model and running the program online, the real-time prediction of the main indicators of sinter quality was realized to guide production promptly. Full article
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21 pages, 10774 KiB  
Article
Hydrogen Embrittlement of Inconel 718 Manufactured by Laser Powder Bed Fusion Using Sustainable Feedstock: Effect of Heat Treatment and Microstructural Anisotropy
by Naveen Karuthodi Mohandas, Alex Giorgini, Matteo Vanazzi, Ton Riemslag, Sean Paul Scott and Vera Popovich
Metals 2023, 13(2), 418; https://doi.org/10.3390/met13020418 - 17 Feb 2023
Cited by 5 | Viewed by 2863
Abstract
This study investigated the in-situ gaseous (under 150 bar) hydrogen embrittlement behaviour of additively manufactured (AM) Inconel 718 produced from sustainable feedstock. Here, sustainable feedstock refers to the Inconel 718 powder produced by vacuum induction melting inert gas atomisation of failed printed parts [...] Read more.
This study investigated the in-situ gaseous (under 150 bar) hydrogen embrittlement behaviour of additively manufactured (AM) Inconel 718 produced from sustainable feedstock. Here, sustainable feedstock refers to the Inconel 718 powder produced by vacuum induction melting inert gas atomisation of failed printed parts or waste from CNC machining. All Inconel 718 samples, namely AM-as-processed, AM-heat-treated and conventional samples showed severe hydrogen embrittlement. Additionally, it was found that despite its higher yield strength (1462 ± 8 MPa) and the presence of δ phase, heat-treated AM Inconel 718 demonstrates 64% lower degree of hydrogen embrittlement compared to the wrought counterpart (Y.S. 1069 ± 4 MPa). This was linked to the anisotropic microstructure induced by the AM process, which was found to cause directional embrittlement unlike the wrought samples showing isotropic embrittlement. In conclusion, this study shows that AM Inconel 718 produced from recycled feedstock shows better hydrogen embrittlement resistance compared to the wrought sample. Furthermore, the unique anisotropic properties, seen in this study for Inconel 718 manufactured by laser powder bed fusion, could be considered further in component design to help minimise the degree of hydrogen embrittlement. Full article
(This article belongs to the Special Issue Additive Manufacturing of High Temperature Alloys)
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14 pages, 13518 KiB  
Article
Reactions and Morphologies of Mg and Mg/Teflon/Viton Particles during Oxidation
by Yifan Li, Jie Wang, Dong Shen, Haoying Liu, Dongming Song and Yanchun Li
Metals 2023, 13(2), 417; https://doi.org/10.3390/met13020417 - 17 Feb 2023
Cited by 2 | Viewed by 1222
Abstract
A thorough investigation on the reactions and morphologies of Mg particles and Mg/Teflon/Viton (MTV) during oxidation were conducted via thermal gravity-differential scanning calorimetry (TG-DSC) and scanning electronic microscopy. The results showed that the oxidation of Mg is fast. It merely changed the metallic [...] Read more.
A thorough investigation on the reactions and morphologies of Mg particles and Mg/Teflon/Viton (MTV) during oxidation were conducted via thermal gravity-differential scanning calorimetry (TG-DSC) and scanning electronic microscopy. The results showed that the oxidation of Mg is fast. It merely changed the metallic luster of Mg before 550 °C, and only a few particles changed to a white irregular shape at 600 °C. However, all of the Mg particles oxidized to porous irregular shaped MgO at 650 °C. Herein, the oxidation of Mg particles ended by its melting point, and the whole process is a solid–gas-phase reaction. On the other hand, when MTV reacted in air, the reaction could be divided into two stages: the fluorination of Mg and the oxidation of the exceeded Mg. In the first stage, a dense MgF2 shell was formed by the solid–solid fluorination. The dense MgF2 shell could impede the oxidation of Mg. As a result, the oxidation of Mg began after its melting. Furthermore, liquid Mg could vaporize at higher temperature, which could burst out from the MgF2 shell and react with oxygen. The MgF2 shell exhibited a dense feature, not only protecting the Mg particles from the heterogeneous oxidation at lower temperature, but also facilitates the homogeneous oxidation at higher temperature. Full article
(This article belongs to the Special Issue Advanced Nano Metallic Fuels Used in Energetic Materials)
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11 pages, 8229 KiB  
Article
The Microstructural Degradation of Ni-Based Superalloys with Segregation under the Super-Gravity Condition
by Guo Yang, Hui Zhou, Xueqiao Li, Wenshuai Wang, Haibo Long, Shengcheng Mao, Ze Zhang and Xiaodong Han
Metals 2023, 13(2), 416; https://doi.org/10.3390/met13020416 - 17 Feb 2023
Viewed by 1547
Abstract
The Ni-based superalloy is used as the turbine blade, which is subject to the coupling effect of temperature and super-gravity during service. As the Ni-based superalloys are difficult to become homogenous after using the solid solution heat treatment, a study on morphology and [...] Read more.
The Ni-based superalloy is used as the turbine blade, which is subject to the coupling effect of temperature and super-gravity during service. As the Ni-based superalloys are difficult to become homogenous after using the solid solution heat treatment, a study on morphology and composition distribution of Ni-base superalloys with segregation during microstructural degradation is necessary. This study investigates the microstructure of the ex-service turbine blade and cast samples subjected to the high-temperature centrifugal test. The difference in the size and shape factor of the γ′ phase decreased with the stress caused by the super-gravity condition, indicating a higher magnitude of homogenization degree. The higher stress will also promote the merge of the sub-grain boundaries, leading to a lower density and higher orientational deviation of the sub-grain boundaries. Full article
(This article belongs to the Special Issue Metal Plasticity and Deformation Mechanism of Metallic Materials)
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10 pages, 3208 KiB  
Article
LaSCA: A Visualization Analysis Tool for Microstructure of Complex Systems
by Zean Tian, Zhongyang Zhang, Xiao Jiang, Feng Wei, Shen Ping and Fan Wu
Metals 2023, 13(2), 415; https://doi.org/10.3390/met13020415 - 17 Feb 2023
Cited by 8 | Viewed by 1239
Abstract
Over the past few decades, plenty of visualization software for the structural analysis of disordered/complex systems has been developed, but the uniqueness and correctness of structural quantification for such systems are still challenging. This paper introduces a visualization analysis tool based on the [...] Read more.
Over the past few decades, plenty of visualization software for the structural analysis of disordered/complex systems has been developed, but the uniqueness and correctness of structural quantification for such systems are still challenging. This paper introduces a visualization analysis tool based on the largest standard cluster analysis (LaSCA), which satisfies the three essential requirements for general structural analysis: physical correctness, objective identification, and injective representation. The specific functionalities of LaSCA include the directed graph model of complex systems, novel structural parameters, topologically close-packed structures, arbitrary partial pair distribution functions, the identification of long-range ordered structures, the adaptive selection of graphical elements, the tracking display of atom ID, user-defined view angles, various options for atom selection, and so on. The program is efficiently based on OpenGL hardware acceleration, employing special algorithms to treat bonds as cylinders or lines and treat atoms as spheres, icosahedrons, tetrahedrons, or points. LaSCA can process more than 1.2 million atoms within 50 s on a PC with 1 GB memory and four cores (Intel Core i7-9700). It is robust and low-cost for surveying short-, medium-, and long-range ordered structures and tracking their evolutions. Full article
(This article belongs to the Section Computation and Simulation on Metals)
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10 pages, 2686 KiB  
Article
Experimental Study on Desulfurization and Removal of Alkali Behavior of BF Slag System in Low-Slag Ironmaking
by Lei Xu, Gele Qing, Xiangfeng Cheng, Meng Xu, Baojun Zhao and Jinfa Liao
Metals 2023, 13(2), 414; https://doi.org/10.3390/met13020414 - 16 Feb 2023
Cited by 1 | Viewed by 1696
Abstract
The increased utilization of pellets in blast furnaces is one of the directions for low-carbon ironmaking. As a result, the low slag rate may affect the desulfurization of the hot metal and the removal of alkali in the blast furnace. Effective desulfurization and [...] Read more.
The increased utilization of pellets in blast furnaces is one of the directions for low-carbon ironmaking. As a result, the low slag rate may affect the desulfurization of the hot metal and the removal of alkali in the blast furnace. Effective desulfurization and the removal of alkali in the low slag ironmaking process have become the focus of the steel industry. In this paper, the effects of slag quantity, temperature, reaction time and slag composition on the desulfurization and removal of alkali were studied using the slag-metal reaction method. It was found that the slag quantity had the same influence trend on the desulfurization and the removal of alkali. The greater the slag quantity, the more effective the desulfurization and the removal of alkali. The slag composition, temperature and reaction time had the opposite effect on the desulfurization and the removal of alkali. High temperature, long reaction time, high MgO concentration, high CaO/SiO2 ratio and low Al2O3 concentration increased the desulfurization of hot metal but reduced the removal rate of alkali from the blast furnace. Applications of the experimental results on high-proportion pellet blast furnace operation are discussed. Full article
(This article belongs to the Special Issue Fundamentals of Advanced Pyrometallurgy)
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14 pages, 3794 KiB  
Article
The Nitrate-Dependent Impact of Carbon Source Starvation on EH40 Steel Corrosion Induced by the Coexistence of Desulfovibrio vulgaris and Pseudomonas aeruginosa
by Wenkai Wang, Zhihua Sun, Jiajia Wu, Dun Zhang, Peng Wang, Ce Li, Liyang Zhu, Yaohua Gao and Yan Sun
Metals 2023, 13(2), 413; https://doi.org/10.3390/met13020413 - 16 Feb 2023
Cited by 1 | Viewed by 1143
Abstract
Carbon source starvation can promote steel corrosion in the presence of a pure culture through extracellular electron transfer (EET). However, the impact of carbon source starvation on corrosion induced by mixed strains is still unknown. This work investigated the impact of carbon source [...] Read more.
Carbon source starvation can promote steel corrosion in the presence of a pure culture through extracellular electron transfer (EET). However, the impact of carbon source starvation on corrosion induced by mixed strains is still unknown. This work investigated the impact of carbon source starvation on EH40 steel corrosion in the presence of Desulfovibrio vulgaris and Pseudomonas aeruginosa, typical species of sulfate- and nitrate-reducing bacteria. It was found that the impact of carbon source starvation on corrosion depended on nitrate addition. When nitrate (5 g∙L−1 NaNO3) was not added, the corrosion was promoted by carbon source starvation. However, the corrosion was initially promoted by carbon source starvation, but later inhibited with nitrate addition. The corrosion behaviors in different systems were closely related to different numbers of the strains in biofilms and their metabolic activities, and the mechanisms were revealed. Full article
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14 pages, 1130 KiB  
Article
Effect of Annealing on the Magnetic Properties of Co2MnSi-Based Heusler Alloy Glass-Coated Microwires
by Mohamed Salaheldeen, Mihail Ipatov, Paula Corte-Leon, Valentina Zhukova and Arcady Zhukov
Metals 2023, 13(2), 412; https://doi.org/10.3390/met13020412 - 16 Feb 2023
Cited by 8 | Viewed by 1304
Abstract
In the current study, we concentrated on the influence of annealing on the magnetic behavior of Co2MnSi-based Heusler microwires. We set the annealing temperature at 1023 K for 2 h, as the sample did not show any significant changes in the [...] Read more.
In the current study, we concentrated on the influence of annealing on the magnetic behavior of Co2MnSi-based Heusler microwires. We set the annealing temperature at 1023 K for 2 h, as the sample did not show any significant changes in the magnetic properties at lower temperatures, while annealing at temperatures above 1023 K damages the glass coating. Strong in-plane magnetocrystalline anisotropy parallel to the microwire axis was evident in the magnetic behavior at room temperature for as-prepared and annealed samples. The coercivity of the annealed sample was four times higher than that of the as-prepared sample across a wide range of measuring temperatures. Both annealed and as-prepared samples exhibit quite stable coercivity behavior with temperature, which may have interesting applications. The an nealed sample did not exhibit magnetic saturation for M-H loops measured below 50 K. Sharp irreversible magnetic behavior has been detected for annealed samples at a blocking temperature of 220 K; at the same time, the blocking temperature for the as-prepared sample was 150 K. The strong internal mechanical stress induced during the fabrication of Co2MnSi microwires in addition to the internal stress relaxation caused by the annealing induced the onset of magnetic phases resulting in unusual and irreversible magnetic behavior. Full article
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14 pages, 4164 KiB  
Article
Effect of Tool Rotation Direction on Mechanical Strength of Single Lap Friction Stir Welded Joints between AA5083 Aluminum Alloy and S355J0 Steel for Maritime Applications
by Guido Di Bella, Chiara Borsellino, Amani Khaskhoussi and Edoardo Proverbio
Metals 2023, 13(2), 411; https://doi.org/10.3390/met13020411 - 16 Feb 2023
Cited by 3 | Viewed by 1204
Abstract
This study aims to investigate a friction stir welded joint between steel and aluminum alloy that is employed in maritime applications (i.e., connection between the ship over-structures and the hull or deck). By changing the tool rotational direction, or the advancing or retreating [...] Read more.
This study aims to investigate a friction stir welded joint between steel and aluminum alloy that is employed in maritime applications (i.e., connection between the ship over-structures and the hull or deck). By changing the tool rotational direction, or the advancing or retreating side, a single lap configuration was studied. Tensile tests were conducted to evaluate the mechanical resistance and the surface fracture after a preliminary investigation consisting of morphological and microstructural analyses and microhardness measurements, with the goal of considering the possibility of replacing the typical joining processes, such as traditional welding or explosion welding, with friction stir welding. The testing showed that the joint produced on the advancing side performed better (+23.5% of the maximum load) than the joint made on the retreating side. Full article
(This article belongs to the Special Issue Environmental Effect on Metal Joining)
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