Evolution and deformability of inclusions in Al-killed steel with rare earth-alkali metals (Ca or Mg) combined treatment

Wang, Yeguang; Liu, Chengjun

doi:10.1016/j.jre.2022.08.005

Cited by 9 publications

(4 citation statements)

References 45 publications

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“…According to the EBSD grain-size statistics (Figure 2b,d), the average grain sizes of the base steel and the rare earth microalloyed steel are about 5.01 µm and 4.47 µm, respectively, which indicates the refinement behavior in RE microalloyed steel; this is similar to other reports in the literature [30]. In addition, the shape, size, and distribution of inclusions in microalloyed steels have a significant effect on the material properties [31,32]. Figure 1b,d illustrate the presence of inclusions with sizes around 3 µm in two microalloyed steels.…”

Section: Microstructure Characteristics Of Re-containing and Re-free ...supporting

confidence: 84%

“…To further investigate the effect of rare earth microalloying on the organization, the inclusions were partially exposed by electrolysis of the substrate with nonaqueous solution, and the EDS technique was used to characterize the inclusions in the microalloyed steels, which will be discussed in the next section. In addition, the shape, size, and distribution of inclusions in microalloyed steels have a significant effect on the material properties [31,32]. Figure 1b,d illustrate the presence of inclusions with sizes around 3 µm in two microalloyed steels.…”

Section: Microstructure Characteristics Of Re-containing and Re-free ...mentioning

confidence: 99%

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Effect of Rare Earth Elements on Microstructure and Tensile Behavior of Nb-Containing Microalloyed Steels

Cheng,

Hou,

Zheng

et al. 2024

Materials

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The present investigation endeavors to explore the influence of rare earth elements on the strength and plasticity characteristics of low-carbon microalloyed steel under tensile loading conditions. The findings from the conducted tensile tests indicate that the incorporation of rare earths leads to a notable enhancement in the yield strength, ultimate tensile strength, and ductility properties of the steel. A comparative analysis of the microstructures reveals that the presence of rare earths significantly refines and optimizes the microstructure of the microalloyed steel. This optimization is manifested through a reduction in grain size, diminution of inclusion sizes, and a concomitant rise in their number density. Moreover, the addition of rare earths is observed to foster an increase in the volumetric fraction of carbides within the steel matrix. These multifaceted microstructural alterations collectively contribute to a substantial strengthening of the microalloyed steel. Furthermore, it is elucidated that the synergistic interaction between rare earth elements and both carbon (C) and niobium (Nb) in the steel matrix augments the extent of the Lüders strain region during the tensile deformation of specimens. This phenomenon is accompanied by the effective modification of inclusions by the rare earths, which serves to mitigate stress concentrations at the interfaces between the inclusions and the surrounding matrix. This article systematically evaluates the modification mechanism of rare earth microalloying, which provides a basis for broadening the application of rare earth microalloying in microalloyed steel.

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Section: Microstructure Characteristics Of Re-containing and Re-free ...supporting

confidence: 84%

Section: Microstructure Characteristics Of Re-containing and Re-free ...mentioning

confidence: 99%

Effect of Rare Earth Elements on Microstructure and Tensile Behavior of Nb-Containing Microalloyed Steels

Cheng,

Hou,

Zheng

et al. 2024

Materials

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“…Since ZnO and C do not belong to the same crystal structure, the two-dimensional disregistry equation is used to describe the crystallographic matching relationship between the substrate phase (C) and the nucleation phase (ZnO), which can reflect the matching degree between different crystal faces between the substrate phase and the nucleation phase. 26 The calculation formula of the two-dimensional disregistry equation is as follows:…”

Section: Crystallographic Analysis Of Zn Eroded Carbon Bricksmentioning

confidence: 99%

Erosion mechanism of harmful elements K and Zn on carbon brick in a 4000 m³ industrial blast furnace hearth

Cao,

Wang,

Zhang

et al. 2024

Ironmaking & Steelmaking: Processes, Products and Applicati

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The carbon bricks eroded by harmful elements after dissection investigation in a Chinese 4000m3 blast furnace hearth is studied in detail. The occurrence state of harmful elements is characterized by chemical analysis, X-ray diffraction and scanning electron microscopy-energy dispersive spectroscopy. The results show that the content of K and Zn in the carbon brick at the tuyere of blast furnace is the highest. ZnO is the main reason for the formation of macro cracks and brittle layer of carbon brick., and K2O and KCl generated by liquid K and blast furnace gas may be the inducements for the formation of brittle layers. The nucleation and growth of ZnO in carbon bricks will undergo three processes: the heterogeneous nucleation of ZnO cell on the surface of C, the heterogeneous nucleation of ZnO cell on the surface of ZnO, and the continuous collision and growth of ZnO cell.

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“…For this reason, researchers have tried to reduce the detriment by changing the phase equilibrium of non-metallic inclusions [22] and controlling the basicity of the refining slag [23]. In addition, calcium treatment is also frequently applied in the control of inclusions in Al-killed steel since calcium treatment can modify clustered Al 2 O 3 inclusions into low-melting point calcium aluminate inclusions [24][25][26], which facilitates the upward removal of inclusions and improves the steel quality. However, Ca wires fed into sulfur-containing steel will react with the sulfur to form CaS, which causes clogging of SENs [27].…”

Section: Introductionmentioning

confidence: 99%

Study on the Evolution Law of Inclusions in the Whole Process and Evaluation of Cleanliness in Start and End of Casting Billets of 42CrMo-S Steel

et al. 2023

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To investigate the evolution law of inclusions in 42CrMo-S steel, this paper samples and analyzes the steel during its refining process as well as the head and tail billets. An oxygen and nitrogen analyzer, a scanning electron microscope (SEM) equipped with energy-dispersive X-ray spectrometry (EDS), and an ASPEX automatic inclusion scanning electron microscope are employed to analyze the cleanliness level of the molten steel in the refining stage and the head and tail billets. The results demonstrate that the total oxygen content at the end of LF slagging is 10.2 ppm, indicating that the refining slag has an excellent deoxygenation effect. During the RH refining process, the total oxygen content of the molten steel diminishes to less than 10 ppm and reaches 6.3 ppm at end-RH. The nitrogen content in the molten steel gradually increases during the smelting process and attains 65 ppm at end-RH. Upon arrival at LF, pure Al2O3 plays the role of the primary inclusions in the molten steel. Afterwards, the pure Al2O3 inclusions transform into Mg-Al spinel-type inclusions, Al2O3-MgO-CaO inclusions, and Al2O3-CaO inclusions. The number of CaS-type inclusions in the steel reaches the maximum after feeding the S wire. In the RH refining stage, the percentage of inclusions with a size less than 5 μm is maintained above 90%. Finally, the cleanliness level of the head and tail billets (the start and end of a casting sequence) is analyzed, and it is recommended that the cut scrap length for the head billet is 0.3 m and the reasonable cutting scrap length for the tail billet is 1 m.

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Evolution and deformability of inclusions in Al-killed steel with rare earth-alkali metals (Ca or Mg) combined treatment

Cited by 9 publications

References 45 publications

Effect of Rare Earth Elements on Microstructure and Tensile Behavior of Nb-Containing Microalloyed Steels

Effect of Rare Earth Elements on Microstructure and Tensile Behavior of Nb-Containing Microalloyed Steels

Erosion mechanism of harmful elements K and Zn on carbon brick in a 4000 m³ industrial blast furnace hearth

Study on the Evolution Law of Inclusions in the Whole Process and Evaluation of Cleanliness in Start and End of Casting Billets of 42CrMo-S Steel

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Evolution and deformability of inclusions in Al-killed steel with rare earth-alkali metals (Ca or Mg) combined treatment

Cited by 9 publications

References 45 publications

Effect of Rare Earth Elements on Microstructure and Tensile Behavior of Nb-Containing Microalloyed Steels

Effect of Rare Earth Elements on Microstructure and Tensile Behavior of Nb-Containing Microalloyed Steels

Erosion mechanism of harmful elements K and Zn on carbon brick in a 4000 m3 industrial blast furnace hearth

Study on the Evolution Law of Inclusions in the Whole Process and Evaluation of Cleanliness in Start and End of Casting Billets of 42CrMo-S Steel

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Erosion mechanism of harmful elements K and Zn on carbon brick in a 4000 m³ industrial blast furnace hearth