To reveal the intricate mechanisms underlying the melting and dissolution processes of scraps in the iron ladle, the melting characteristics of three carbon steels with different C concentrations at the bath temperatures of 1623 and 1723 K were studied. Upon immersing scraps into the molten metal, the liquid metal immediately froze around the submerged parts of scrap cylinders. Whereafter, the solid shell completely melted at both bath temperatures after the immersion time of 5 s. The maximum thickness of solidified steel shells significantly decreased with increasing the bath temperature. The findings also suggested that the melting rate of scrap cylinder exhibited a positive correlation with the C concentration in the scrap and the bath temperature. Quantitatively, the mass transfer coefficients of C for the low carbon (0.18 wt.%), medium carbon (0.32 wt.%), and high carbon (0.61 wt.%) concentrations in the scrap cylinders at 1723 K were determined by a kinetic model, which were 8.78 × 10−5, 9.57 × 10−5 and 10.00 × 10−5 m s−1, respectively, and those corresponding values decreased to 3.87 × 10−5, 4.49 × 10−5 and 3.54 × 10−5 m s−1 at 1623 K. However, there was little difference observed among the heat transfer coefficients of hot metal for the three carbon steels, which were estimated to have an average value of 16.36 and 18.82 kW m−2 K−1 at the experimental temperatures of 1623 and 1723 K, respectively. The results from the experiments and mathematical models showed good consistency at both bath temperatures, providing feasible guidance for efficient melting of steel scraps in the iron ladle.
为了揭示废钢在铁水包中熔化和溶解过程的复杂机制,我们研究了三种不同C浓度的碳钢在1623和1723 K熔池温度下的熔化特性。将废料浸入熔融金属后,废料圆柱体浸没部分周围的液态金属立即冻结。此后,在两种熔池温度下,浸入时间均为 5 秒后,固态外壳完全熔化。研究结果还表明,废钢圆柱体的熔化率与废钢中的 C 浓度和熔池温度呈正相关。通过动力学模型定量测定了 1723 K 时废钢圆柱体中低碳(0.18 wt.%)、中碳(0.32 wt.%)和高碳(0.61 wt.%)浓度下的碳传质系数,分别为 8.78 × 10-5、9.57 × 10-5 和 10.00 × 10-5 m s-1,相应的数值分别下降到 3.不过,三种碳钢的热金属传热系数差别不大,在 1623 和 1723 K 的实验温度下,估计平均值分别为 16.36 和 18.82 kW m-2 K-1。实验结果和数学模型在两种熔池温度下都显示出良好的一致性,为在铁水包中高效熔化钢渣提供了可行的指导。
{"title":"Effect of carbon concentration on melting behavior of steel scraps in hot metal baths","authors":"Wei Liu, Cheng-song Liu, Cheng-jie Song, Yong Wang, Wan-jun Zhu, Hua Zhang, Hong-wei Ni","doi":"10.1007/s42243-024-01273-8","DOIUrl":"https://doi.org/10.1007/s42243-024-01273-8","url":null,"abstract":"<p>To reveal the intricate mechanisms underlying the melting and dissolution processes of scraps in the iron ladle, the melting characteristics of three carbon steels with different C concentrations at the bath temperatures of 1623 and 1723 K were studied. Upon immersing scraps into the molten metal, the liquid metal immediately froze around the submerged parts of scrap cylinders. Whereafter, the solid shell completely melted at both bath temperatures after the immersion time of 5 s. The maximum thickness of solidified steel shells significantly decreased with increasing the bath temperature. The findings also suggested that the melting rate of scrap cylinder exhibited a positive correlation with the C concentration in the scrap and the bath temperature. Quantitatively, the mass transfer coefficients of C for the low carbon (0.18 wt.%), medium carbon (0.32 wt.%), and high carbon (0.61 wt.%) concentrations in the scrap cylinders at 1723 K were determined by a kinetic model, which were 8.78 × 10<sup>−5</sup>, 9.57 × 10<sup>−5</sup> and 10.00 × 10<sup>−5</sup> m s<sup>−1</sup>, respectively, and those corresponding values decreased to 3.87 × 10<sup>−5</sup>, 4.49 × 10<sup>−5</sup> and 3.54 × 10<sup>−5</sup> m s<sup>−1</sup> at 1623 K. However, there was little difference observed among the heat transfer coefficients of hot metal for the three carbon steels, which were estimated to have an average value of 16.36 and 18.82 kW m<sup>−2</sup> K<sup>−1</sup> at the experimental temperatures of 1623 and 1723 K, respectively. The results from the experiments and mathematical models showed good consistency at both bath temperatures, providing feasible guidance for efficient melting of steel scraps in the iron ladle.</p>","PeriodicalId":16151,"journal":{"name":"Journal of Iron and Steel Research International","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141551897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-03DOI: 10.1007/s42243-024-01269-4
Xiao-hui Fan, Zhi-an Zhou, Bin-bin Huang, Zhi-yun Ji, Min Gan, Zeng-qing Sun, Xu-ling Chen, Xiao-xian Huang, Guo-jing Wang
The municipal solid waste incineration fly ash (MSWI-FA) contains a large amount of heavy metals, and the process of iron ore sintering and treating fly ash needs to pay attention to the migration characteristics of heavy metals. The impact of the application of MSWI-FA in the sintering process on the emission law of heavy metals in the collaborative treatment process was studied, and corresponding control technologies were proposed. The results showed that the direct addition of water washing fly ash (WM-FA) powder resulted in varying degrees of increase in heavy metal elements in the sinter. As the amount of WM-FA added increases, the content of heavy metal elements correspondingly increases, and an appropriate amount of WM-FA added is 0.5%–1.0%. The migration mechanism of heavy metals during the sintering treatment of WM-FA was clarified. Heavy metals are mainly removed through direct and indirect chlorination reactions, and Cu and Cr can react with SiO2 and Fe2O3 in the sintered material to solidify in the sinter. Corresponding control techniques have been proposed to reduce the heavy metal elements in WM-FA through the pre-treatment of WM-FA. When the WM-FA was fed in the middle and lower layers of the sintered material, the high temperature of the lower layer was utilized to promote the removal of heavy metals. The Ni element content has decreased from 130 to 90 mg kg−1, and the Cd removal rate has increased by 23%. The removal rates of Cd and Cr elements increase by 2.4 and 5.5 times, respectively. There is no significant change in sintering indexes.
{"title":"Emission characteristics and control technology of heavy metals during collaborative treatment of municipal solid waste incineration fly ash in iron ore sintering process","authors":"Xiao-hui Fan, Zhi-an Zhou, Bin-bin Huang, Zhi-yun Ji, Min Gan, Zeng-qing Sun, Xu-ling Chen, Xiao-xian Huang, Guo-jing Wang","doi":"10.1007/s42243-024-01269-4","DOIUrl":"https://doi.org/10.1007/s42243-024-01269-4","url":null,"abstract":"<p>The municipal solid waste incineration fly ash (MSWI-FA) contains a large amount of heavy metals, and the process of iron ore sintering and treating fly ash needs to pay attention to the migration characteristics of heavy metals. The impact of the application of MSWI-FA in the sintering process on the emission law of heavy metals in the collaborative treatment process was studied, and corresponding control technologies were proposed. The results showed that the direct addition of water washing fly ash (WM-FA) powder resulted in varying degrees of increase in heavy metal elements in the sinter. As the amount of WM-FA added increases, the content of heavy metal elements correspondingly increases, and an appropriate amount of WM-FA added is 0.5%–1.0%. The migration mechanism of heavy metals during the sintering treatment of WM-FA was clarified. Heavy metals are mainly removed through direct and indirect chlorination reactions, and Cu and Cr can react with SiO<sub>2</sub> and Fe<sub>2</sub>O<sub>3</sub> in the sintered material to solidify in the sinter. Corresponding control techniques have been proposed to reduce the heavy metal elements in WM-FA through the pre-treatment of WM-FA. When the WM-FA was fed in the middle and lower layers of the sintered material, the high temperature of the lower layer was utilized to promote the removal of heavy metals. The Ni element content has decreased from 130 to 90 mg kg<sup>−1</sup>, and the Cd removal rate has increased by 23%. The removal rates of Cd and Cr elements increase by 2.4 and 5.5 times, respectively. There is no significant change in sintering indexes.</p>","PeriodicalId":16151,"journal":{"name":"Journal of Iron and Steel Research International","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141500910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The La1.7Pr0.3Mg16Ni hydrogen storage alloy was prepared by medium-frequency induction melting, and then the composite hydrogen storage alloy powder of La1.7Pr0.3Mg16Ni + x wt.% (x = 0, 2, 4, and 6) graphene was prepared by ball milling for 10 h. The effect of the addition of graphene on the activation and hydrogen de/absorption properties of La1.7Pr0.3Mg16Ni alloy was studied. The result demonstrated that these composite alloys were composed of La2Mg17, La2Ni3, and Mg2Ni phases. After saturated hydrogen absorption, it was composed of LaH3, Mg2NiH4, and MgH2 phases, while during the dehydrogenation process, it was composed of LaH3, Mg, and Mg2Ni phases. The addition of graphene can help get a more homogeneous granule after ball milling and accelerate the first activation of dehydrogenation/hydrogen absorption. The hydrogen release activation energy of the alloys first decreases and then increases as the graphene content increases from x = 0 wt.% to x = 6 wt.%. The minimum activation energy of the composite hydrogen storage alloy is 51.22 kJ mol−1 when x = 4 wt.%.
{"title":"Effect of graphene addition on activation and kinetic properties of La–Mg–Ni-based hydrogen storage alloys","authors":"Dian-chen Feng, Chun-ling Zheng, Zhi-yuan Zhao, Dong-sheng Zhou, Hui-ping Ren, Yang-huan Zhang","doi":"10.1007/s42243-024-01262-x","DOIUrl":"https://doi.org/10.1007/s42243-024-01262-x","url":null,"abstract":"<p>The La<sub>1.7</sub>Pr<sub>0.3</sub>Mg<sub>16</sub>Ni hydrogen storage alloy was prepared by medium-frequency induction melting, and then the composite hydrogen storage alloy powder of La<sub>1.7</sub>Pr<sub>0.3</sub>Mg<sub>16</sub>Ni + <i>x</i> wt.% (<i>x</i> = 0, 2, 4, and 6) graphene was prepared by ball milling for 10 h. The effect of the addition of graphene on the activation and hydrogen de/absorption properties of La<sub>1.7</sub>Pr<sub>0.3</sub>Mg<sub>16</sub>Ni alloy was studied. The result demonstrated that these composite alloys were composed of La<sub>2</sub>Mg<sub>17</sub>, La<sub>2</sub>Ni<sub>3</sub>, and Mg<sub>2</sub>Ni phases. After saturated hydrogen absorption, it was composed of LaH<sub>3</sub>, Mg<sub>2</sub>NiH<sub>4</sub>, and MgH<sub>2</sub> phases, while during the dehydrogenation process, it was composed of LaH<sub>3</sub>, Mg, and Mg<sub>2</sub>Ni phases. The addition of graphene can help get a more homogeneous granule after ball milling and accelerate the first activation of dehydrogenation/hydrogen absorption. The hydrogen release activation energy of the alloys first decreases and then increases as the graphene content increases from <i>x</i> = 0 wt.% to <i>x</i> = 6 wt.%. The minimum activation energy of the composite hydrogen storage alloy is 51.22 kJ mol<sup>−1</sup> when <i>x</i> = 4 wt.%.</p>","PeriodicalId":16151,"journal":{"name":"Journal of Iron and Steel Research International","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141500941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-01DOI: 10.1007/s42243-024-01263-w
Tao-tao Li, Hong-de Ding, Rui-feng Li, Kai Qi, Zhen-guang Liu, Xiao-qiang Zhang, Yue Zhao, Lei Qiao
Pinless friction stir spot welding (P-FSSW) was performed to manufacture Mg/steel lap joints. Orthogonal tests for P-FSSW of Mg/steel were investigated, and the main factors affecting the properties of Mg/steel lap joints were derived. The shear force of the Mg/steel lap joints gradually increased and then decreased as the welding time increased. Maximum shear force was 5.3 kN. Fe–Al intermetallic compound (IMC) was formed at the Mg/steel interface near the steel side, and Mg–Al IMCs were formed at the Mg/steel interface near the Mg alloy side. Mg/steel lap joint was transformed from an initial solid-state welding to fusion-brazing welding as the welding time increased. No hole defects were formed in Mg/steel solid-state welding joints, whereas hole defects appeared in Mg/steel fusion-brazing welding joints. The temperature field of Mg/steel lap joints was simulated to analyze hole defects generated during the welding process. Hole defects can be eliminated by changing the spindle deflection angle, and the shear force decreased. Excessive spindle deflection can also lead to failure to form a stable joint. Hole defects were removed because the spindle deflection angle reduced the interfacial reaction temperature, and a solid-state welding joint was formed, which resulted in an absence of fusion-brazing welding hole formation.
{"title":"Hole inhibition mechanisms of Mg/steel lap joint by pinless friction stir spot welding","authors":"Tao-tao Li, Hong-de Ding, Rui-feng Li, Kai Qi, Zhen-guang Liu, Xiao-qiang Zhang, Yue Zhao, Lei Qiao","doi":"10.1007/s42243-024-01263-w","DOIUrl":"https://doi.org/10.1007/s42243-024-01263-w","url":null,"abstract":"<p>Pinless friction stir spot welding (P-FSSW) was performed to manufacture Mg/steel lap joints. Orthogonal tests for P-FSSW of Mg/steel were investigated, and the main factors affecting the properties of Mg/steel lap joints were derived. The shear force of the Mg/steel lap joints gradually increased and then decreased as the welding time increased. Maximum shear force was 5.3 kN. Fe–Al intermetallic compound (IMC) was formed at the Mg/steel interface near the steel side, and Mg–Al IMCs were formed at the Mg/steel interface near the Mg alloy side. Mg/steel lap joint was transformed from an initial solid-state welding to fusion-brazing welding as the welding time increased. No hole defects were formed in Mg/steel solid-state welding joints, whereas hole defects appeared in Mg/steel fusion-brazing welding joints. The temperature field of Mg/steel lap joints was simulated to analyze hole defects generated during the welding process. Hole defects can be eliminated by changing the spindle deflection angle, and the shear force decreased. Excessive spindle deflection can also lead to failure to form a stable joint. Hole defects were removed because the spindle deflection angle reduced the interfacial reaction temperature, and a solid-state welding joint was formed, which resulted in an absence of fusion-brazing welding hole formation.</p>","PeriodicalId":16151,"journal":{"name":"Journal of Iron and Steel Research International","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141500911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ti3SiC2 ceramic and SUS430 ferritic stainless steel were welded by the transient liquid phase (TLP) diffusion bonding method using an Al interlayer at 850–1050 °C in vacuum. The evolution of phase and morphology at the interface and bonding strength were systematically investigated. The results show that Ti3SiC2 and SUS430 were well bonded at 900–950 °C. Three reaction zones were observed at the interface. At the joint interface area adjacent to alloy, the alloy completely reacted with liquid Al to form Al86Fe14. At Ti3SiC2/Al interface, Ti and Si diffused outward from Ti3SiC2 into the molten Al to form Fe3Al + Al5FeSi + TiAl3 zone. Adjacent to Ti3SiC2 matrix, Ti3Si(Al)C2 + TiCx zone was formed by the loss of Si. The evolution mechanism of TLP-bonded joints was discussed based on the interface microstructure and product phases. In addition, the tensile strength of the joint increased with increasing bonding temperature. The corresponding maximum value of 59.7 MPa was obtained from SUS430/Al (10 μm)/Ti3SiC2 joint prepared at 950 °C.
采用瞬态液相(TLP)扩散键合方法,在 850-1050 °C 真空条件下使用铝中间膜焊接了 Ti3SiC2 陶瓷和 SUS430 铁素体不锈钢。系统地研究了界面上的相和形态演变以及结合强度。结果表明,Ti3SiC2 和 SUS430 在 900-950 ℃ 时结合良好。在界面上观察到三个反应区。在邻近合金的接合界面区域,合金与液态铝完全反应形成 Al86Fe14。在 Ti3SiC2/Al 界面,Ti 和 Si 从 Ti3SiC2 向外扩散到熔融 Al 中,形成 Fe3Al + Al5FeSi + TiAl3 区。紧邻 Ti3SiC2 基体的 Ti3Si(Al)C2 + TiCx 区则因 Si 的流失而形成。根据界面微观结构和产物相讨论了 TLP 粘合接头的演变机制。此外,接头的抗拉强度随着粘合温度的升高而增加。在 950 °C 下制备的 SUS430/Al (10 μm)/Ti3SiC2 接头的相应最大值为 59.7 MPa。
{"title":"Microstructure and mechanical properties of transient liquid phase bonding Ti3SiC2 ceramic to SUS430 steel using an Al interlayer","authors":"Jing-xiang Zhao, Xi-chao Li, Jing Shi, Qiang Cheng, Bin Xu, Ming-yue Sun, Li-li Zheng","doi":"10.1007/s42243-024-01265-8","DOIUrl":"https://doi.org/10.1007/s42243-024-01265-8","url":null,"abstract":"<p>Ti<sub>3</sub>SiC<sub>2</sub> ceramic and SUS430 ferritic stainless steel were welded by the transient liquid phase (TLP) diffusion bonding method using an Al interlayer at 850–1050 °C in vacuum. The evolution of phase and morphology at the interface and bonding strength were systematically investigated. The results show that Ti<sub>3</sub>SiC<sub>2</sub> and SUS430 were well bonded at 900–950 °C. Three reaction zones were observed at the interface. At the joint interface area adjacent to alloy, the alloy completely reacted with liquid Al to form Al<sub>86</sub>Fe<sub>14</sub>. At Ti<sub>3</sub>SiC<sub>2</sub>/Al interface, Ti and Si diffused outward from Ti<sub>3</sub>SiC<sub>2</sub> into the molten Al to form Fe<sub>3</sub>Al + Al<sub>5</sub>FeSi + TiAl<sub>3</sub> zone. Adjacent to Ti<sub>3</sub>SiC<sub>2</sub> matrix, Ti<sub>3</sub>Si(Al)C<sub>2</sub> + TiC<sub><i>x</i></sub> zone was formed by the loss of Si. The evolution mechanism of TLP-bonded joints was discussed based on the interface microstructure and product phases. In addition, the tensile strength of the joint increased with increasing bonding temperature. The corresponding maximum value of 59.7 MPa was obtained from SUS430/Al (10 μm)/Ti<sub>3</sub>SiC<sub>2</sub> joint prepared at 950 °C.</p>","PeriodicalId":16151,"journal":{"name":"Journal of Iron and Steel Research International","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141500942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-22DOI: 10.1007/s42243-024-01243-0
Wei Zhang, Wen-yong Dai
Lightweight refractories for the working lining of high-temperature furnaces play an important role in the smelting of advanced steels and superalloys. To prepare lightweight refractories for the working lining of high-temperature furnaces, the synthesis of lightweight aggregates is the basis. Recently, the research on the synthesis of lightweight aggregates with high service temperature, low thermal conductivity, high strength, and good slag resistance has received widespread attention. The available literature on the synthesis of lightweight aggregates was summarized, including corundum, mullite, mullite–corundum, spinel, corundum–spinel, cordierite, cordierite–mullite, calcium hexaluminate, corundum–calcium hexaluminate, bauxite, magnesia, magnesia-based, and forsterite-based aggregates. Finally, the future development trend of lightweight aggregates was proposed.
{"title":"State of the art of lightweight aggregates used in lightweight refractories for working lining of high-temperature furnaces","authors":"Wei Zhang, Wen-yong Dai","doi":"10.1007/s42243-024-01243-0","DOIUrl":"https://doi.org/10.1007/s42243-024-01243-0","url":null,"abstract":"<p>Lightweight refractories for the working lining of high-temperature furnaces play an important role in the smelting of advanced steels and superalloys. To prepare lightweight refractories for the working lining of high-temperature furnaces, the synthesis of lightweight aggregates is the basis. Recently, the research on the synthesis of lightweight aggregates with high service temperature, low thermal conductivity, high strength, and good slag resistance has received widespread attention. The available literature on the synthesis of lightweight aggregates was summarized, including corundum, mullite, mullite–corundum, spinel, corundum–spinel, cordierite, cordierite–mullite, calcium hexaluminate, corundum–calcium hexaluminate, bauxite, magnesia, magnesia-based, and forsterite-based aggregates. Finally, the future development trend of lightweight aggregates was proposed.</p>","PeriodicalId":16151,"journal":{"name":"Journal of Iron and Steel Research International","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141500943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-21DOI: 10.1007/s42243-024-01235-0
Ming Li, Jun Fu, Neng Ren, Biao Tao, Alan Scholes, Jun Li, Jian-guo Li, Hong-biao Dong
We proposed a new technique route of directional solidification for the manufacture of super slab. A 7-t laboratory-scale thick slab was casted and characterised for trial. To further understand the process, the evolution of the multiple physical fields during the directional solidification was simulated and verified. Similar to the convectional ingot casting, a negative segregated cone of equiaxed grains was formed at the bottom, and a seriously positive segregated region was formed beneath the top surface of the slab. Specific measures on the lateral walls, base plate, and free surface were strongly recommended to ensure that the slab is relatively directionally casted. A water-cooling copper base plate accelerates the solidification rate and the columnar growth along the vertical direction. It inhibits the sedimentation of equiaxed grains and enlarges the columnar zone. Based on the simulation analysis, it can be concluded that the directional solidification technique route is promising to manufacture super slab with lower segregation level, and less porosities and inclusions.
{"title":"Numerical simulation and experimental investigation of manufacturing route of directional casting super slab","authors":"Ming Li, Jun Fu, Neng Ren, Biao Tao, Alan Scholes, Jun Li, Jian-guo Li, Hong-biao Dong","doi":"10.1007/s42243-024-01235-0","DOIUrl":"https://doi.org/10.1007/s42243-024-01235-0","url":null,"abstract":"<p>We proposed a new technique route of directional solidification for the manufacture of super slab. A 7-t laboratory-scale thick slab was casted and characterised for trial. To further understand the process, the evolution of the multiple physical fields during the directional solidification was simulated and verified. Similar to the convectional ingot casting, a negative segregated cone of equiaxed grains was formed at the bottom, and a seriously positive segregated region was formed beneath the top surface of the slab. Specific measures on the lateral walls, base plate, and free surface were strongly recommended to ensure that the slab is relatively directionally casted. A water-cooling copper base plate accelerates the solidification rate and the columnar growth along the vertical direction. It inhibits the sedimentation of equiaxed grains and enlarges the columnar zone. Based on the simulation analysis, it can be concluded that the directional solidification technique route is promising to manufacture super slab with lower segregation level, and less porosities and inclusions.</p>","PeriodicalId":16151,"journal":{"name":"Journal of Iron and Steel Research International","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141500944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The phase volume fraction has an important role in the match of the strength and plasticity of dual phase steel. The different bainite contents (18–53 vol.%) in polygonal ferrite and bainite (PF + B) dual phase steel were obtained by controlling the relaxation finish temperature during the rolling process. The effect of bainite volume fraction on the tensile deformability was systematically investigated via experiments and crystal plasticity finite element model (CPFEM) simulation. The experimental results showed that the steel showed optimal strain hardenability and strength–plasticity matching when the bainite reached 35%. The 3D-CPFEM models with the same grain size and texture characters were established to clarify the influence of stress/strain distribution on PF + B dual phase steel with different bainite contents. The simulation results indicated that an appropriate increase in the bainite content (18%–35%) did not affect the interphase strain difference, but increased the stress distribution in both phases, as a result of enhancing the coordinated deformability of two phases and improving the strength–plasticity matching. When the bainite content increased to 53%, the stress/strain difference between the two phases was greatly increased, and plastic damage between the two phases was caused by the reduction of the coordinated deformability.
{"title":"Effect of phase content on deformation compatibility in ferrite and bainite dual-phase steel: experimental and crystal plasticity finite element analysis","authors":"Xian-bo Shi, Xing-yang Tu, Bing-chuan Yan, Yi Ren, Wei Yan, Yi-yin Shan","doi":"10.1007/s42243-024-01232-3","DOIUrl":"https://doi.org/10.1007/s42243-024-01232-3","url":null,"abstract":"<p>The phase volume fraction has an important role in the match of the strength and plasticity of dual phase steel. The different bainite contents (18–53 vol.%) in polygonal ferrite and bainite (PF + B) dual phase steel were obtained by controlling the relaxation finish temperature during the rolling process. The effect of bainite volume fraction on the tensile deformability was systematically investigated via experiments and crystal plasticity finite element model (CPFEM) simulation. The experimental results showed that the steel showed optimal strain hardenability and strength–plasticity matching when the bainite reached 35%. The 3D-CPFEM models with the same grain size and texture characters were established to clarify the influence of stress/strain distribution on PF + B dual phase steel with different bainite contents. The simulation results indicated that an appropriate increase in the bainite content (18%–35%) did not affect the interphase strain difference, but increased the stress distribution in both phases, as a result of enhancing the coordinated deformability of two phases and improving the strength–plasticity matching. When the bainite content increased to 53%, the stress/strain difference between the two phases was greatly increased, and plastic damage between the two phases was caused by the reduction of the coordinated deformability.</p>","PeriodicalId":16151,"journal":{"name":"Journal of Iron and Steel Research International","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141500946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-18DOI: 10.1007/s42243-024-01225-2
Ao Zhu, Chen-ying Shi, Pei-yuan Ni, Teng-fei Deng
Understanding the phase equilibria of the Fe3O4–Cr2O3–CaO system is essential for the efficient recycling of stainless steel pickling sludge. The isothermal section of this system at 1473 K under oxygen partial pressure of 0.15 Pa was investigated. Key experiments on the relevant binary systems were conducted using a combination of equilibrium-quenching techniques, X-ray diffraction, high-resolution transmission electron microscope, and electron probe microanalysis. These systems were rigorously assessed using the CALPHAD (CALculation of Phase Diagram) method, incorporating the present experimental data. The liquid phase was modeled using the ionic two-sublattice model, represented as (Ca2+, Cr3+, Fe2+)P(O2−, Va, FeO1.5)Q, where Va represents vacancy, and P and Q denote the number of sites on the cation and anion sublattices, respectively. To ensure electroneutrality, the values of P and Q adjust according to the composition of the mixture. From this, the isothermal section of the Fe3O4–Cr2O3–CaO system at 1473 K under the specified oxygen partial pressure was obtained based on the thermodynamic parameters of the binary systems. The present experimental data and calculation results hold significant implications for the comprehensive recycling of stainless steel pickling sludge.
了解 Fe3O4-Cr2O3-CaO 体系的相平衡对于高效回收不锈钢酸洗污泥至关重要。研究了该体系在 1473 K 氧分压为 0.15 Pa 条件下的等温段。结合使用平衡淬火技术、X 射线衍射、高分辨率透射电子显微镜和电子探针显微分析,对相关二元体系进行了关键实验。结合目前的实验数据,使用 CALPHAD(相图计算)方法对这些体系进行了严格评估。液相模型采用离子双亚晶格模型,表示为 (Ca2+, Cr3+, Fe2+)P(O2-, Va, FeO1.5)Q,其中 Va 代表空位,P 和 Q 分别表示阳离子和阴离子亚晶格上的位点数。为确保电中性,P 和 Q 的值会根据混合物的成分进行调整。由此,根据二元体系的热力学参数,得出了 Fe3O4-Cr2O3-CaO 体系在指定氧分压下于 1473 K 的等温段。本实验数据和计算结果对不锈钢酸洗污泥的综合回收利用具有重要意义。
{"title":"Phase equilibria of Fe3O4–Cr2O3–CaO system: experimental measurements and thermodynamic calculations","authors":"Ao Zhu, Chen-ying Shi, Pei-yuan Ni, Teng-fei Deng","doi":"10.1007/s42243-024-01225-2","DOIUrl":"https://doi.org/10.1007/s42243-024-01225-2","url":null,"abstract":"<p>Understanding the phase equilibria of the Fe<sub>3</sub>O<sub>4</sub>–Cr<sub>2</sub>O<sub>3</sub>–CaO system is essential for the efficient recycling of stainless steel pickling sludge. The isothermal section of this system at 1473 K under oxygen partial pressure of 0.15 Pa was investigated. Key experiments on the relevant binary systems were conducted using a combination of equilibrium-quenching techniques, X-ray diffraction, high-resolution transmission electron microscope, and electron probe microanalysis. These systems were rigorously assessed using the CALPHAD (CALculation of Phase Diagram) method, incorporating the present experimental data. The liquid phase was modeled using the ionic two-sublattice model, represented as (Ca<sup>2+</sup>, Cr<sup>3+</sup>, Fe<sup>2+</sup>)<sub><i>P</i></sub>(O<sup>2−</sup>, Va, FeO<sub>1.5</sub>)<sub><i>Q</i></sub>, where Va represents vacancy, and <i>P</i> and <i>Q</i> denote the number of sites on the cation and anion sublattices, respectively. To ensure electroneutrality, the values of <i>P</i> and <i>Q</i> adjust according to the composition of the mixture. From this, the isothermal section of the Fe<sub>3</sub>O<sub>4</sub>–Cr<sub>2</sub>O<sub>3</sub>–CaO system at 1473 K under the specified oxygen partial pressure was obtained based on the thermodynamic parameters of the binary systems. The present experimental data and calculation results hold significant implications for the comprehensive recycling of stainless steel pickling sludge.</p>","PeriodicalId":16151,"journal":{"name":"Journal of Iron and Steel Research International","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141500947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-18DOI: 10.1007/s42243-024-01255-w
Xi-qing Chen, Pu Wang, Shun Liu, Hong Xiao, Lin-lin Lei, Jia-quan Zhang
Obtaining a reasonable mold flow field for casting slabs with different sections is challenging by solely modifying the nozzle structure and continuous casting process. Research was conducted on small-sectioned (1000 mm × 220 mm) and large-sectioned (3250 mm × 220 mm) slab continuous casting molds with a fixed nozzle form (concave bottom nozzle, side port inclination angle of 0°). A three-dimensional electromagnetic model is established to analyze the current frequency, installation position, and rotation angle under the active deceleration mode and acceleration mode. The results indicate that, regardless of the deceleration mode for small-sectioned slabs or the acceleration mode for large-sectioned slabs, the magnetic flux density in the mold decreases with increasing current frequency. However, the maximum electromagnetic force initially increases and then decreases, suggesting that both electromagnetic modes have the same optimal current frequency (3 Hz). The optimal mechanical design parameters for the deceleration mode of electromagnetic variable flow device (EM-VFD) with the small-sectioned slab are as follows: installation position Z = 115 mm and rotation angle of 15°, ensuring that the maximum electromagnetic force is applied to the nozzle jet area. For the acceleration mode of the large-sectioned slab EM-VFD, the optimal mechanical design parameters are as follows: Z = 115 mm and rotation angle of 10°, ensuring that the maximum electromagnetic force is applied to 1/4 and 3/4 areas of the wide face. These findings indicate that the new electromagnetic variable flow device, which can actively adjust the flow rate and angle of the steel even under given working conditions, provides the possibility for reasonable control of the mold’s flow field.
{"title":"New electromagnetic variable flow device for slab continuous casting mold: mechanical design and magnetic field analysis","authors":"Xi-qing Chen, Pu Wang, Shun Liu, Hong Xiao, Lin-lin Lei, Jia-quan Zhang","doi":"10.1007/s42243-024-01255-w","DOIUrl":"https://doi.org/10.1007/s42243-024-01255-w","url":null,"abstract":"<p>Obtaining a reasonable mold flow field for casting slabs with different sections is challenging by solely modifying the nozzle structure and continuous casting process. Research was conducted on small-sectioned (1000 mm × 220 mm) and large-sectioned (3250 mm × 220 mm) slab continuous casting molds with a fixed nozzle form (concave bottom nozzle, side port inclination angle of 0°). A three-dimensional electromagnetic model is established to analyze the current frequency, installation position, and rotation angle under the active deceleration mode and acceleration mode. The results indicate that, regardless of the deceleration mode for small-sectioned slabs or the acceleration mode for large-sectioned slabs, the magnetic flux density in the mold decreases with increasing current frequency. However, the maximum electromagnetic force initially increases and then decreases, suggesting that both electromagnetic modes have the same optimal current frequency (3 Hz). The optimal mechanical design parameters for the deceleration mode of electromagnetic variable flow device (EM-VFD) with the small-sectioned slab are as follows: installation position <i>Z</i> = 115 mm and rotation angle of 15°, ensuring that the maximum electromagnetic force is applied to the nozzle jet area. For the acceleration mode of the large-sectioned slab EM-VFD, the optimal mechanical design parameters are as follows: <i>Z</i> = 115 mm and rotation angle of 10°, ensuring that the maximum electromagnetic force is applied to 1/4 and 3/4 areas of the wide face. These findings indicate that the new electromagnetic variable flow device, which can actively adjust the flow rate and angle of the steel even under given working conditions, provides the possibility for reasonable control of the mold’s flow field.</p>","PeriodicalId":16151,"journal":{"name":"Journal of Iron and Steel Research International","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141500945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}