Mykyta Levchenko, Oleksandr Kovtun, Alberto Angelini, Hans Peter Markus, Dariusz Sosin, Rie Endo, Olena Volkova
Viscosity, density, and surface tension of an industrial electric arc furnace (EAF) slag from production of construction steel with varying SiO2 and Al2O3 contents are investigated using a rotating viscometer and the maximum bubble pressure method. In addition, influence of thermophysical properties on foaming index is discussed. To predict the behavior of the solid phase in the slag at different temperatures, thermodynamic calculations are performed using FactSage 8.1 software. The experiments demonstratethat SiO2 and Al2O3 act as network formers in the studied slag systems, resulting in increased viscosity values in the liquid‐dominant region and decreased density of the slag. The presence of alumina and silica altered the behavior of the slag in the liquid‐dominant region, shifting the breaking point of the slags. Furthermore, the addition of silica decreases the surface tension of the slag, confirming its role as a surfactant. However, the addition of Al2O3 increases the surface tension due to the high surface tension of pure alumina. Consequently, the foaming index of the slag can increase by ≈40%, primarily due to the polymerization of the slag.
{"title":"Effect of SiO2 and Al2O3 on the Thermophysical Properties and the Foaming Index of Electric Arc Interface Slag from the Production of Construction Steel","authors":"Mykyta Levchenko, Oleksandr Kovtun, Alberto Angelini, Hans Peter Markus, Dariusz Sosin, Rie Endo, Olena Volkova","doi":"10.1002/srin.202400476","DOIUrl":"https://doi.org/10.1002/srin.202400476","url":null,"abstract":"Viscosity, density, and surface tension of an industrial electric arc furnace (EAF) slag from production of construction steel with varying SiO<jats:sub>2</jats:sub> and Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> contents are investigated using a rotating viscometer and the maximum bubble pressure method. In addition, influence of thermophysical properties on foaming index is discussed. To predict the behavior of the solid phase in the slag at different temperatures, thermodynamic calculations are performed using FactSage 8.1 software. The experiments demonstratethat SiO<jats:sub>2</jats:sub> and Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> act as network formers in the studied slag systems, resulting in increased viscosity values in the liquid‐dominant region and decreased density of the slag. The presence of alumina and silica altered the behavior of the slag in the liquid‐dominant region, shifting the breaking point of the slags. Furthermore, the addition of silica decreases the surface tension of the slag, confirming its role as a surfactant. However, the addition of Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> increases the surface tension due to the high surface tension of pure alumina. Consequently, the foaming index of the slag can increase by ≈40%, primarily due to the polymerization of the slag.","PeriodicalId":21929,"journal":{"name":"steel research international","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, the thermophysical properties of low‐sulfur manganese–boron steel with varying boron and sulfur contents at different temperatures are investigated. Density and surface tension are measured between 1550 and 1650 °C using the maximum bubble pressure method, while viscosity is examined between 1530 and 1570 °C using an improved oscillating crucible viscometer. The methods yield results with low error, consistent with existing literature. The density of the base steel decreases from 7057 ± 25 kg m−3 at 1550 °C to 6843 ± 85 kg m−3 at 1650 °C. The addition of boron (up to 57 ppm) and sulfur (up to 130 ppm) does not significantly change the density. Sulfur, increasing from 39 to 130 ppm, reduces the surface tension from 1416 ± 12 to 1302 ± 9 mN m−1 at 1650 °C. Boron's effect on surface tension varies, possibly influenced by other elements like oxygen. Viscosity ranges from 5.74 to 6.44 mPa s, with boron and sulfur additions causing minimal changes, the largest deviation being 8%. In these results, valuable data for the simulation, modeling, control, and optimization of liquid steel processing are provided.
{"title":"Density, Surface Tension, and Viscosity of Liquid Low‐Sulfur Manganese–Boron Steel via Maximum Bubble Pressure and Oscillating Crucible Methods","authors":"Matheus Roberto Bellé, Lukas Neubert, Anastasiia Sherstneva, Taisei Yamamoto, Tsuyoshi Nishi, Hidemasa Yamano, Matthias Weinberg, Olena Volkova","doi":"10.1002/srin.202400252","DOIUrl":"https://doi.org/10.1002/srin.202400252","url":null,"abstract":"In this study, the thermophysical properties of low‐sulfur manganese–boron steel with varying boron and sulfur contents at different temperatures are investigated. Density and surface tension are measured between 1550 and 1650 °C using the maximum bubble pressure method, while viscosity is examined between 1530 and 1570 °C using an improved oscillating crucible viscometer. The methods yield results with low error, consistent with existing literature. The density of the base steel decreases from 7057 ± 25 kg m<jats:sup>−3</jats:sup> at 1550 °C to 6843 ± 85 kg m<jats:sup>−3</jats:sup> at 1650 °C. The addition of boron (up to 57 ppm) and sulfur (up to 130 ppm) does not significantly change the density. Sulfur, increasing from 39 to 130 ppm, reduces the surface tension from 1416 ± 12 to 1302 ± 9 mN m<jats:sup>−1</jats:sup> at 1650 °C. Boron's effect on surface tension varies, possibly influenced by other elements like oxygen. Viscosity ranges from 5.74 to 6.44 mPa s, with boron and sulfur additions causing minimal changes, the largest deviation being 8%. In these results, valuable data for the simulation, modeling, control, and optimization of liquid steel processing are provided.","PeriodicalId":21929,"journal":{"name":"steel research international","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tae Sung Kim, Geun Ho Park, Dong Woon Kim, Joo Hyun Park
The effects of Si content of steel melts containing 1.5% Al as well as alloying sequence of Si and Al on the evolution of inclusions are investigated. The SiO2 inclusion is primarily formed when Si (=0.5–3.0 wt%) is added to the melts at 1873 K, and the area fraction (AF) of the inclusions decreases over time. The subsequent addition of 1.5% Al to the Si‐alloyed steel (i.e., 3.0Si→1.5Al) increases the AF of inclusions due to the formation of Al2O3. The population density function (PDF) analysis for the preferential Si alloying shows a fractal distribution, indicating that the inclusions grow by a collision mechanism. PDF analysis shows a lognormal distribution because Al2O3 inclusion is formed and grows after subsequent Al alloying. Alternatively, when 1.5% Al is preferentially added to steel, Al2O3 clusters are formed. The AF of Al2O3 cluster decreases over time. When 3.0% Si is subsequently added to the Al‐alloyed steel (i.e., 1.5Al→3.0Si), singular Al2O3 particles are mainly observed. Because the Al alloying results in the formation of Al2O3 regardless of the alloying sequence and Si content, it is important to float up and separate Al2O3 cluster to improve the cleanliness of high‐Si‐Al‐alloyed steels such as electrical steels.
研究了含 1.5% Al 的钢熔体中 Si 含量以及 Si 和 Al 的合金化顺序对夹杂物演变的影响。当在 1873 K 时向熔体中添加 Si（=0.5-3.0 wt%）时，主要会形成 SiO2 夹杂，并且夹杂物的面积分数 (AF) 会随着时间的推移而降低。随后在硅合金钢中加入 1.5% Al（即 3.0Si→1.5Al），由于 Al2O3 的形成，夹杂物的面积分数增加。优先硅合金化的种群密度函数（PDF）分析显示出分形分布，表明夹杂物是通过碰撞机制生长的。PDF 分析显示出对数正态分布，这是因为 Al2O3 包裹体在随后的 Al 合金后形成并增长。另外，在钢中优先添加 1.5% Al 时，会形成 Al2O3 簇。随着时间的推移，Al2O3 簇的 AF 会逐渐减少。当随后向铝合金钢中添加 3.0% 的 Si 时（即 1.5Al→3.0Si），主要会观察到单个的 Al2O3 颗粒。由于无论合金化顺序和 Si 含量如何，Al 合金都会导致 Al2O3 的形成，因此浮起和分离 Al2O3 簇对于提高高 SiAl 合金钢（如电工钢）的清洁度非常重要。
{"title":"Evolution Mechanism of Nonmetallic Inclusions in Fe‐1.5Al‐xSi (x = 0.5–3.0 wt%) Alloyed Steels","authors":"Tae Sung Kim, Geun Ho Park, Dong Woon Kim, Joo Hyun Park","doi":"10.1002/srin.202400491","DOIUrl":"https://doi.org/10.1002/srin.202400491","url":null,"abstract":"The effects of Si content of steel melts containing 1.5% Al as well as alloying sequence of Si and Al on the evolution of inclusions are investigated. The SiO<jats:sub>2</jats:sub> inclusion is primarily formed when Si (=0.5–3.0 wt%) is added to the melts at 1873 K, and the area fraction (AF) of the inclusions decreases over time. The subsequent addition of 1.5% Al to the Si‐alloyed steel (i.e., 3.0Si→1.5Al) increases the AF of inclusions due to the formation of Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>. The population density function (PDF) analysis for the preferential Si alloying shows a fractal distribution, indicating that the inclusions grow by a collision mechanism. PDF analysis shows a lognormal distribution because Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> inclusion is formed and grows after subsequent Al alloying. Alternatively, when 1.5% Al is preferentially added to steel, Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> clusters are formed. The AF of Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> cluster decreases over time. When 3.0% Si is subsequently added to the Al‐alloyed steel (i.e., 1.5Al→3.0Si), singular Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> particles are mainly observed. Because the Al alloying results in the formation of Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> regardless of the alloying sequence and Si content, it is important to float up and separate Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> cluster to improve the cleanliness of high‐Si‐Al‐alloyed steels such as electrical steels.","PeriodicalId":21929,"journal":{"name":"steel research international","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ida B. G. S. Adhiwiguna, Gökhan Karagülmez, Onur Keskin, Rüdiger Deike
In this study, the prospective application of lime as a desulfurization agent for the cast‐iron industry is technically examined. This investigation encompasses a series of laboratory experiments conducted under atmospheric conditions, mirroring industrial settings by exploring two distinct methods for introducing lime powder onto and into molten cast iron using surface addition and gas injection techniques. Deoxidation agents (FeSi, SiC, and Al) are also incorporated to enhance the lime‐based desulfurization results. Based on the findings of this study, it is indicated that lime can be a reliable cast‐iron desulfurization agent by reaching an end‐sulfur concentration of <0.015 wt%, thus providing an opportunity for a sustainable alternative for the foundry industry. In this study, it is also revealed that adding a small quantity of Al is more effective at enhancing desulfurization results than Si due to its role in increasing the proportion of liquid slag during desulfurization. However, caution is advised regarding the limit of aluminum concentration in cast iron (0.1 wt%), and treatment temperatures should be kept above 1400 °C to prevent counterproductive effects and undesirable defects in the product.
本研究从技术上考察了石灰作为脱硫剂在铸铁工业中的应用前景。这项研究包括一系列在大气条件下进行的实验室实验，通过探索使用表面添加和气体注入技术将石灰粉引入熔融铸铁的两种不同方法，反映了工业环境。此外，还加入了脱氧剂（FeSi、SiC 和 Al），以提高石灰脱硫效果。根据这项研究的结果，石灰可以成为一种可靠的铸铁脱硫剂，其最终硫含量可达到 0.015 wt%，从而为铸造业提供了一种可持续的替代方法。这项研究还表明，添加少量 Al 比添加 Si 更能有效提高脱硫效果，因为 Al 在脱硫过程中能增加液态渣的比例。不过，建议注意铸铁中铝浓度的限制（0.1 wt%），处理温度应保持在 1400 °C 以上，以防止产生反作用和产品中的不良缺陷。
{"title":"Investigation on Applicability of Lime as Desulfurization Agent for Molten Cast Iron","authors":"Ida B. G. S. Adhiwiguna, Gökhan Karagülmez, Onur Keskin, Rüdiger Deike","doi":"10.1002/srin.202400416","DOIUrl":"https://doi.org/10.1002/srin.202400416","url":null,"abstract":"In this study, the prospective application of lime as a desulfurization agent for the cast‐iron industry is technically examined. This investigation encompasses a series of laboratory experiments conducted under atmospheric conditions, mirroring industrial settings by exploring two distinct methods for introducing lime powder onto and into molten cast iron using surface addition and gas injection techniques. Deoxidation agents (FeSi, SiC, and Al) are also incorporated to enhance the lime‐based desulfurization results. Based on the findings of this study, it is indicated that lime can be a reliable cast‐iron desulfurization agent by reaching an end‐sulfur concentration of <0.015 wt%, thus providing an opportunity for a sustainable alternative for the foundry industry. In this study, it is also revealed that adding a small quantity of Al is more effective at enhancing desulfurization results than Si due to its role in increasing the proportion of liquid slag during desulfurization. However, caution is advised regarding the limit of aluminum concentration in cast iron (0.1 wt%), and treatment temperatures should be kept above 1400 °C to prevent counterproductive effects and undesirable defects in the product.","PeriodicalId":21929,"journal":{"name":"steel research international","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Davide Mombelli, Gianluca Dall’Osto, Sara Scolari, Carlo Mapelli, Roberto Moreschi, Roberto Marras, Riccardo Morandi
Among the steelmaking slag, secondary metallurgy slag (SMS) is the most problematic to be recycled. Several attempts to recover such slag as lime replacement, slag flux, pozzolanic materials have been made for long time with pros and cons. However, the amount of recyclable slag is limited and often their employment requires higher energy demand than traditional materials. Nevertheless, the use of SMS in agriculture is poorly or never considered. In this article, the legal and technical evaluation of SMS as raw material for fertilizers production is investigated. Compliance of technical specification, toxic metals concentration, and leaching behavior allows to confirm the technical feasibility of SMS use as a raw material for fertilizers manufacture. Both from the literature data and the experimental results on 16 industrial SMS samples, the requirements for calcium‐magnesium‐sulfur‐based fertilizers, soil correctives and for sanitizing agricultural sewage sludge, appear fully satisfied. The CaO concentration in SMS (35–60 wt%) is abundantly higher than the requirements (≥15 wt%) and CaO is present in most part as water‐soluble complexes such as calcium aluminates (70 wt%), silicates (10 wt%), and sulfide (4 wt%). The pH of the SMS samples leachate is comparable to that of fresh lime (12.35 vs 12.46), highlighting a better behavior for sewage sludge sanitation with respect to limestone (9.98). The measured toxic metals and leachate elements concentration over the corresponding admittable threshold are always lower than 0.5 and 1.0 (mg kg−1/mg kg−1) for liming materials. Finally, these results lead to officially approve the use of SMS as soil corrective according to the Italian Fertilizer Regulation.
{"title":"The Use of Secondary Metallurgy Slag as Soil Corrective in Agriculture: Approval of Their Application in Italy","authors":"Davide Mombelli, Gianluca Dall’Osto, Sara Scolari, Carlo Mapelli, Roberto Moreschi, Roberto Marras, Riccardo Morandi","doi":"10.1002/srin.202400310","DOIUrl":"https://doi.org/10.1002/srin.202400310","url":null,"abstract":"Among the steelmaking slag, secondary metallurgy slag (SMS) is the most problematic to be recycled. Several attempts to recover such slag as lime replacement, slag flux, pozzolanic materials have been made for long time with pros and cons. However, the amount of recyclable slag is limited and often their employment requires higher energy demand than traditional materials. Nevertheless, the use of SMS in agriculture is poorly or never considered. In this article, the legal and technical evaluation of SMS as raw material for fertilizers production is investigated. Compliance of technical specification, toxic metals concentration, and leaching behavior allows to confirm the technical feasibility of SMS use as a raw material for fertilizers manufacture. Both from the literature data and the experimental results on 16 industrial SMS samples, the requirements for calcium‐magnesium‐sulfur‐based fertilizers, soil correctives and for sanitizing agricultural sewage sludge, appear fully satisfied. The CaO concentration in SMS (35–60 wt%) is abundantly higher than the requirements (≥15 wt%) and CaO is present in most part as water‐soluble complexes such as calcium aluminates (70 wt%), silicates (10 wt%), and sulfide (4 wt%). The pH of the SMS samples leachate is comparable to that of fresh lime (12.35 vs 12.46), highlighting a better behavior for sewage sludge sanitation with respect to limestone (9.98). The measured toxic metals and leachate elements concentration over the corresponding admittable threshold are always lower than 0.5 and 1.0 (mg kg<jats:sup>−1</jats:sup>/mg kg<jats:sup>−1</jats:sup>) for liming materials. Finally, these results lead to officially approve the use of SMS as soil corrective according to the Italian Fertilizer Regulation.","PeriodicalId":21929,"journal":{"name":"steel research international","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Christian Bernhard, Georg Gaiser, Michael Bernhard, Johann Winkler, Maximilian Kern, Peter Presoly, Youn‐Bae Kang
In the course of the decarbonization of steel production, electric steel production will continue to gain importance. The processing of low‐quality scrap will also play an important role, which may lead to an increase in the content of so‐called tramp elements in steel production and further processing. This article examines the effect of the elements Cu, Sn, and Ni on the formation of surface cracks under the conditions of the continuous casting process. Results of an in situ bending test are compared with the results of the experimental simulation of high‐temperature oxidation and thermodynamic analysis based on the CALculation of PHase Diagrams (CALPHAD) approach. For a temperature of 900 °C, an equivalent Cu content of 0.20 wt% must be considered as the critical upper limit. The presumable reason is the existence of Cu‐ and Sn‐rich liquid phases at the austenite grain boundaries. The results clearly show the effect of the investigated elements but also point to the importance of the gas atmosphere and cooling conditions on the results. This can be a groundbreaking result for extending the process window for casting steels with increased tramp element contents.
在钢铁生产去碳化的过程中，电炉钢生产将继续占据重要地位。劣质废钢的加工也将发挥重要作用，这可能导致钢铁生产和深加工中所谓杂质元素含量的增加。本文研究了铜、锡和镍元素在连铸工艺条件下对表面裂纹形成的影响。原位弯曲试验结果与高温氧化实验模拟结果以及基于相图计算（CALPHAD）方法的热力学分析结果进行了比较。对于 900 °C 的温度，必须将 0.20 wt% 的等效铜含量视为临界上限。原因可能是奥氏体晶界存在富含铜和锡的液相。结果清楚地显示了所研究元素的影响，但也指出了气体环境和冷却条件对结果的重要性。这对于延长杂散元素含量增加的铸钢的工艺窗口来说，可能是一个突破性的结果。
{"title":"On the Role of Tramp Elements for Surface Defect Formation in Continuous Casting of Steel","authors":"Christian Bernhard, Georg Gaiser, Michael Bernhard, Johann Winkler, Maximilian Kern, Peter Presoly, Youn‐Bae Kang","doi":"10.1002/srin.202400494","DOIUrl":"https://doi.org/10.1002/srin.202400494","url":null,"abstract":"In the course of the decarbonization of steel production, electric steel production will continue to gain importance. The processing of low‐quality scrap will also play an important role, which may lead to an increase in the content of so‐called tramp elements in steel production and further processing. This article examines the effect of the elements Cu, Sn, and Ni on the formation of surface cracks under the conditions of the continuous casting process. Results of an in situ bending test are compared with the results of the experimental simulation of high‐temperature oxidation and thermodynamic analysis based on the CALculation of PHase Diagrams (CALPHAD) approach. For a temperature of 900 °C, an equivalent Cu content of 0.20 wt% must be considered as the critical upper limit. The presumable reason is the existence of Cu‐ and Sn‐rich liquid phases at the austenite grain boundaries. The results clearly show the effect of the investigated elements but also point to the importance of the gas atmosphere and cooling conditions on the results. This can be a groundbreaking result for extending the process window for casting steels with increased tramp element contents.","PeriodicalId":21929,"journal":{"name":"steel research international","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dongyue Zheng, Wenzeng Zhao, Xingfu Yu, Yong Su, Yinghua Wei
By means of microstructure observation, phase analysis, and mechanical‐property tests, the effect of martensite–bainite (M–B) duplex microstructure on carbide precipitation and mechanical properties of M50 steel is studied. In that results, it is shown that the distribution of secondary carbides in specimens with M–B duplex microstructure is more uniform and finer, and the stability of retained austenite (RA) in the steel is also improved, so that the content of RA in specimens with M–B duplex microstructure is 2.34%, which is higher than the 0.94% of the specimens with full martensite microstructure. The M–B duplex microstructure leads to the reduction of tempering hardness of M50 steel to 60.9 unit of Rockwell hardness (HRC), compared to the 61.6 HRC of the specimens with full martensite microstructure, but the wear resistance is slightly enhanced. Moreover, the M–B duplex microstructure effectively improves the impact toughness and fatigue properties by refining the microstructure and carbides in the steel, and the increase amplitude is 47.4% and 41.0%, respectively.
{"title":"Effect of Martensite–Bainite Duplex Microstructure on Carbide Precipitation and Mechanical Properties of M50 Steel","authors":"Dongyue Zheng, Wenzeng Zhao, Xingfu Yu, Yong Su, Yinghua Wei","doi":"10.1002/srin.202400570","DOIUrl":"https://doi.org/10.1002/srin.202400570","url":null,"abstract":"By means of microstructure observation, phase analysis, and mechanical‐property tests, the effect of martensite–bainite (M–B) duplex microstructure on carbide precipitation and mechanical properties of M50 steel is studied. In that results, it is shown that the distribution of secondary carbides in specimens with M–B duplex microstructure is more uniform and finer, and the stability of retained austenite (RA) in the steel is also improved, so that the content of RA in specimens with M–B duplex microstructure is 2.34%, which is higher than the 0.94% of the specimens with full martensite microstructure. The M–B duplex microstructure leads to the reduction of tempering hardness of M50 steel to 60.9 unit of Rockwell hardness (HRC), compared to the 61.6 HRC of the specimens with full martensite microstructure, but the wear resistance is slightly enhanced. Moreover, the M–B duplex microstructure effectively improves the impact toughness and fatigue properties by refining the microstructure and carbides in the steel, and the increase amplitude is 47.4% and 41.0%, respectively.","PeriodicalId":21929,"journal":{"name":"steel research international","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For sintering pot productive process with various fuel particle size distributions, a transient numerical simulation sintering model based on the computational fluid dynamics approach is developed using Fluent 2021R1. The model combines chemical reaction, mass and heat transfer, Euler–Euler model, and fluid flow in porous media. In this study, CO is employed as the combustion's intermediate product, which is further oxidized by secondary combustion in the high‐temperature zone. Through calculations, the solid fuel combustion behavior of the sintering is explained collectively with the changing bed temperature, CO emission, and solid fuel combustion efficiency of the process under various fuel particle size distribution. In the sintering process, the fuel particle size distribution is crucial for lowering CO emissions and increasing combustion efficiency. The combustion efficiency shows a tendency of increasing initially before decreasing with the reduction of solid fuel particle size, while CO emissions show a trend of reducing first and then increasing. It is advantageous to lower the CO emission in the sintering process, and the combustion efficiency of the sintering process is greatly boosted by 5.13% when the proportion of solid fuel with 5 mm particle size decreases and the proportion of solid fuel with 3 mm particle size increases.
针对各种燃料粒度分布的烧结锅生产过程，使用 Fluent 2021R1 开发了基于计算流体动力学方法的瞬态数值模拟烧结模型。该模型结合了化学反应、传质和传热、欧拉-欧拉模型以及多孔介质中的流体流动。本研究采用 CO 作为燃烧的中间产物，在高温区通过二次燃烧进一步氧化。通过计算，对不同燃料粒度分布下烧结过程中的床温变化、CO 排放和固体燃料燃烧效率等固体燃料燃烧行为进行了综合解释。在烧结过程中，燃料粒度分布对降低 CO 排放和提高燃烧效率至关重要。随着固体燃料粒度的减小，燃烧效率呈现先升高后降低的趋势，而 CO 排放量则呈现先降低后升高的趋势。降低烧结过程中的 CO 排放量是有利的，当粒径为 5 毫米的固体燃料比例减少，粒径为 3 毫米的固体燃料比例增加时，烧结过程的燃烧效率将大大提高 5.13%。
{"title":"Numerical Simulation of CO Generation and Combustion Efficiency in Sintering Process: Effect of Solid Fuel Particle Size","authors":"Zhen Li, Yaozu Wang, Jianliang Zhang, Sida Li, Lele Niu, Zhengjian Liu, Hao Liu","doi":"10.1002/srin.202400094","DOIUrl":"https://doi.org/10.1002/srin.202400094","url":null,"abstract":"For sintering pot productive process with various fuel particle size distributions, a transient numerical simulation sintering model based on the computational fluid dynamics approach is developed using Fluent 2021R1. The model combines chemical reaction, mass and heat transfer, Euler–Euler model, and fluid flow in porous media. In this study, CO is employed as the combustion's intermediate product, which is further oxidized by secondary combustion in the high‐temperature zone. Through calculations, the solid fuel combustion behavior of the sintering is explained collectively with the changing bed temperature, CO emission, and solid fuel combustion efficiency of the process under various fuel particle size distribution. In the sintering process, the fuel particle size distribution is crucial for lowering CO emissions and increasing combustion efficiency. The combustion efficiency shows a tendency of increasing initially before decreasing with the reduction of solid fuel particle size, while CO emissions show a trend of reducing first and then increasing. It is advantageous to lower the CO emission in the sintering process, and the combustion efficiency of the sintering process is greatly boosted by 5.13% when the proportion of solid fuel with 5 mm particle size decreases and the proportion of solid fuel with 3 mm particle size increases.","PeriodicalId":21929,"journal":{"name":"steel research international","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yiming Duan, Shuai Chao, Xi Zhang, Junguo Li, Yaling Zhang, Chunhui Gu, Jiale He
As a byproduct of the steelmaking process, ladle slag has the potential to be used as an auxiliary cement material in the construction field. However, ladle slag generated after secondary refining is typically handled by air cooling and stacking, leading to the presence of the typical mineral phase mayenite (Ca12Al14O33, abbreviated as C12A7) in a crystalline form within the slag. This reduces its early hydration activity, which adversely affects the compressive strength of concrete and consequently lowers the resource utilization rate of ladle slag. Based on this, this article provides a comprehensive review of the generation process and composition of ladle slag. By discussing the hydration process and hydration products of the typical mineral phase C12A7 in ladle slag, as well as the mutual transformation of hydration products, it is shown that hydration products undergo transformation with increasing temperature. Compared to crystalline C12A7, amorphous, C12A7 exhibits excellent hydration activity. Building upon this, methods for amorphizing C12A7 are elucidated, wherein thermal activation or chemical activation is employed to alter the ordered arrangement of atoms within the crystal structure, thereby reducing the stability of the crystal structure to achieve amorphization of C12A7.
{"title":"The Hydration Activity Enhancement Method of Mayenite in Ladle Slag: A Review","authors":"Yiming Duan, Shuai Chao, Xi Zhang, Junguo Li, Yaling Zhang, Chunhui Gu, Jiale He","doi":"10.1002/srin.202400355","DOIUrl":"https://doi.org/10.1002/srin.202400355","url":null,"abstract":"As a byproduct of the steelmaking process, ladle slag has the potential to be used as an auxiliary cement material in the construction field. However, ladle slag generated after secondary refining is typically handled by air cooling and stacking, leading to the presence of the typical mineral phase mayenite (Ca<jats:sub>12</jats:sub>Al<jats:sub>14</jats:sub>O<jats:sub>33</jats:sub>, abbreviated as C<jats:sub>12</jats:sub>A<jats:sub>7</jats:sub>) in a crystalline form within the slag. This reduces its early hydration activity, which adversely affects the compressive strength of concrete and consequently lowers the resource utilization rate of ladle slag. Based on this, this article provides a comprehensive review of the generation process and composition of ladle slag. By discussing the hydration process and hydration products of the typical mineral phase C<jats:sub>12</jats:sub>A<jats:sub>7</jats:sub> in ladle slag, as well as the mutual transformation of hydration products, it is shown that hydration products undergo transformation with increasing temperature. Compared to crystalline C<jats:sub>12</jats:sub>A<jats:sub>7</jats:sub>, amorphous, C<jats:sub>12</jats:sub>A<jats:sub>7</jats:sub> exhibits excellent hydration activity. Building upon this, methods for amorphizing C<jats:sub>12</jats:sub>A<jats:sub>7</jats:sub> are elucidated, wherein thermal activation or chemical activation is employed to alter the ordered arrangement of atoms within the crystal structure, thereby reducing the stability of the crystal structure to achieve amorphization of C<jats:sub>12</jats:sub>A<jats:sub>7</jats:sub>.","PeriodicalId":21929,"journal":{"name":"steel research international","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hongchao Ji, Wei Liu, Weimin Liu, Xiaomin Huang, Changzhe Song, Shengqiang Liu
The liner is affixed to the inner side of the ball mill cylinder to protect the cylinder. Through isothermal compression experiments, Arrhenius constitutive models, peak strain models, critical strain models, dynamic recrystallization dynamic models, and grain size models suitable for the forging process of Mn–Cr–Ni–Mo steel used in ball mill liners were established. By utilizing Deform software, a 3D thermo‐force‐structure coupling model for the hot forging process of ball mill liners was constructed, and the volume fraction of dynamic recrystallization and average grain size during forging was predicted. The response surface model was employed to investigate how process parameters interacted with each other and affected microstructure uniformity in ball mill liners. After optimization, the optimal parameters were determined: initial forging temperature at 1200 °C, forging speed at 30 mm s−1, and friction coefficient at 0.3. Subsequently, a hot forging experiment on ball mill liners was conducted using these optimized parameters; samples were analyzed through backscattered electron diffraction device experiments and microscopic tissue observations. Results demonstrated that microstructural changes observed during actual forging processes aligned with numerical simulation results—thus verifying both the accuracy of the Mn–Cr–Ni–Mo steel material model and numerical simulation method.
{"title":"Prediction of Microstructure Evolution in Ball Mill Liner Forging Process","authors":"Hongchao Ji, Wei Liu, Weimin Liu, Xiaomin Huang, Changzhe Song, Shengqiang Liu","doi":"10.1002/srin.202400479","DOIUrl":"https://doi.org/10.1002/srin.202400479","url":null,"abstract":"The liner is affixed to the inner side of the ball mill cylinder to protect the cylinder. Through isothermal compression experiments, Arrhenius constitutive models, peak strain models, critical strain models, dynamic recrystallization dynamic models, and grain size models suitable for the forging process of Mn–Cr–Ni–Mo steel used in ball mill liners were established. By utilizing Deform software, a 3D thermo‐force‐structure coupling model for the hot forging process of ball mill liners was constructed, and the volume fraction of dynamic recrystallization and average grain size during forging was predicted. The response surface model was employed to investigate how process parameters interacted with each other and affected microstructure uniformity in ball mill liners. After optimization, the optimal parameters were determined: initial forging temperature at 1200 °C, forging speed at 30 mm s<jats:sup>−1</jats:sup>, and friction coefficient at 0.3. Subsequently, a hot forging experiment on ball mill liners was conducted using these optimized parameters; samples were analyzed through backscattered electron diffraction device experiments and microscopic tissue observations. Results demonstrated that microstructural changes observed during actual forging processes aligned with numerical simulation results—thus verifying both the accuracy of the Mn–Cr–Ni–Mo steel material model and numerical simulation method.","PeriodicalId":21929,"journal":{"name":"steel research international","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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