Effect of Cerium on the Microstructure and Inclusion Evolution of C-Mn Cryogenic Vessel Steels

Wu, Liping; Zhi, Junge; Zhang, Jiangshan; Zhao, Bin; Liu, Qing

doi:10.3390/ma14185262

Cited by 8 publications

(7 citation statements)

References 29 publications

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“…The inclusions of 55SiCrA spring steel were identified to be Al 2 O 3 –SiO 2 , CaO–Al 2 O 3 –SiO 2 , MgO–CaO–Al 2 O 3 –SiO 2 , and MnS. Some studies have shown MnS precipitates during solidification process, [ 30,31 ] which are related to the cooling rate, and S and Mn contents in steel. [ 32,33 ] In this study, the analysis and discussion are focused on the evolution of the oxide inclusions.…”

Section: Resultsmentioning

confidence: 99%

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Evolution Mechanism of MgO–Al₂O₃–SiO₂–CaO Inclusions During Continuous Casting of Si‐Killed Spring Steel

Wang

Wei

Zhang

et al. 2022

steel research int.

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Spring steel is extensively utilized in various sectors, such as automotive, engineering machinery, and electric power sectors, owing to its excellent elasticity. [1][2][3] The industries have stringent fatigue performances requirement for their products. [4] Inclusions are common sources of early fatigue faults, [5] which can cause premature spring fracture. For manufacturing highquality spring steel, a deep understanding of the formation and evolution of the inclusions in spring steel is essential.Si and Mn are commonly used as deoxidizers in high-quality spring steel. [6] Si-Mn-killed spring steel has inclusions with a low melting point, which deform more easily during rolling than the inclusions of Al-killed spring steel, thereby decreasing the damage of the inclusions on the fatigue life of the spring. [7] Al 2 O 3 and MgO-Al 2 O 3 inclusions with a high melting point can be formed with an excessively high Al content in steel. These inclusions can block the nozzle and shorten the fatigue life of spring. [8] Thus, alloys with a low Al content and refining slag are used to regulate the Al content in molten steel. [9][10][11] Inclusions form and evolve dynamically during continuous casting (CC) because of the continuous variations in the thermodynamic equilibrium between molten steel and inclusions in CC. According to Choudhary et al., [12] MnO-SiO 2 -Al 2 O 3 and Al 2 O 3 inclusions are formed during the solidification of Si-Mn-killed lowcarbon steel. They [13] further investigated the formation and evolution of the inclusions in low-carbon Al-killed steel during CC and predicted the types of precipitates with varying Mg contents. From their results, the Mg content in molten steel during ladle treatment should be kept below 0.8 ppm to prevent the formation of MgO•Al 2 O 3 spinel inclusions, which is consistent with the results of Ben. [14] Sonja et al. [15] observed an increase in the number of liquid inclusions in the steel and the formation of MnO-Al 2 O 3 spinel inclusions when the temperature dropped during the solidification of Si-Mn-killed steel. Goto et al. [16] investigated the influence of the initial oxides on the precipitation and growth of oxides during the solidification of Mn-killed steel. During solidification, the formation and growth of MnO-FeO oxides were independent of the initial oxide. Saburo et al. [17] discovered the relationship between the initial contents of Al and O in molten steel and changes in the Al 2 O 3 content in the MnO-SiO 2 -Al 2 O 3 inclusions during solidification. The inclusions were more stable during cooling with high initial amounts of Al and O. Zhong et al. [18] investigated the cooling process of silicon steel, whereby the precipitates were found to be mullite. The cooling rate had a significant impact on the precipitation and growth of the oxides. In particular, a slower cooling rate was beneficial for reducing the number of inclusions. Holappa et al. [19] investigated the evolution of the inclusions in Ca-treated Al-killed steels during solidification. They found ...

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Section: Resultsmentioning

confidence: 99%

“…MnS. Some studies have shown MnS precipitates during solidification process, [30,31] which are related to the cooling rate, and S and Mn contents in steel. [32,33] In this study, the analysis and discussion are focused on the evolution of the oxide inclusions.…”

Section: Andmentioning

confidence: 99%

Evolution Mechanism of MgO–Al₂O₃–SiO₂–CaO Inclusions During Continuous Casting of Si‐Killed Spring Steel

Wang

Wei

Zhang

et al. 2022

steel research int.

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“…As a result, the criteria for cryogenic vessel steels have become increasingly stringent. [1][2][3] The choice of steel for cryogenic vessels necessitates high strength, high ductility, and exceptional low-temperature toughness. [4,5] To date, the most extensively studied cryogenic vessel material is nickel steel.…”

Section: Introductionmentioning

confidence: 99%

Tailoring Low‐Alloyed Cryogenic Steel Strong and Tough Introduces Fine‐Grained Equiaxed Ferrite by Intercritical Subquenching

Ding,

Wang,

Liu

et al. 2024

steel research int.

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Herein, a novel approach is developed to enhance the strength, ductility, and low‐temperature toughness of high‐strength low‐alloy steels, overcoming the traditional trade‐off. By incorporating an intercritical subquenching step during the conventional quenching and tempering (QT) process, a microstructure featuring refined lath bainite and a small amount of fine equiaxed ferrite is achieved. The resulting steel exhibits a strength similar to that of QT steel with significantly improved ductility and low‐temperature impact toughness. Compared to traditional QT steel, the new process steel maintains a similar strength. In addition, the elongation increases from ~22.2% to ~24.9%, and the impact energy significantly increases at −50 °C from ~233 to ~347 J. The fine grain size and dense lath structure contribute to the minimal reduction in strength. The presence of equiaxed ferrite and bainite improves the ductility, while plastic deformation and special grain boundaries play a crucial role in enhancing the low‐temperature toughness. This innovative heat treatment method offers an economical solution for producing high‐strength low‐alloy cryogenic vessel steels without compromising strength while greatly improving ductility and low‐temperature toughness.

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“…Furthermore, calcium, rare earths, etc. were utilized to promote the formation of fine sulfides which are more stable and have a higher melting point than that of manganese sulfides [13][14][15]. Imagumbai et al [16] proposed that the quantity of MnS inclusions increased with the increase in cooling rate, while the average size decreased.…”

Section: Introductionmentioning

confidence: 99%

Study on MnS Inclusion Aggregation along Continuous Casting Slab Thickness of Medium Carbon Structural Steel

Yang

Lai

et al. 2021

Metals

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Precipitation of MnS inclusions in steel affects the mechanical properties of the material significantly. The evolution of MnS inclusions along the continuous casting slab thickness and its influencing factors has not been clearly established and comprehensively studied. In this paper, solidification macrostructure, sulfur segregation and MnS inclusions in the continuous casting slab of medium carbon structural steel 45# were studied by various methods, including the metallographic observations, elemental analysis, scanning electron microscope (SEM) with Energy Dispersive Spectrometer (EDS) observation, automatic particle analysis, and thermodynamic calculations. The 2D/3D morphologies of MnS inclusions suggest that the sulfides turn from globular to rodlike, and further to dendritic shape along the slab thickness progressively. Furthermore, it was found that MnS inclusions are remarkably aggregated in the columnar crystals and the equiaxed crystals mixed zone, where the sulfides have the largest average diameter of 6.35 μm and the second maximum area fraction of 0.025% along the slab thickness. In order to reveal the mechanism of this phenomenon, the precipitation temperature of MnS inclusion in the 45# steel was clarified by thermodynamic calculation and experimental observation, and the quantitative relationships among the distribution of sulfur content, secondary dendrite arm spacing (SDAS), and precipitation area fraction of MnS inclusions were discussed. Moreover, the inclusion size was numerically predicted to compare with the measured value. The results indicate that the large SDAS, high sulfur content and low cooling rate accounting for the large-size aggregated MnS inclusions in the mixed zone. Unfortunately, the dendritic MnS inclusions, even if the average diameter exceeds 52 μm, can act as the nucleation sites for ferrites, and the distribution of the sulfides promotes uneven microstructure in the steel.

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Effect of Cerium on the Microstructure and Inclusion Evolution of C-Mn Cryogenic Vessel Steels

Cited by 8 publications

References 29 publications

Evolution Mechanism of MgO–Al₂O₃–SiO₂–CaO Inclusions During Continuous Casting of Si‐Killed Spring Steel

Evolution Mechanism of MgO–Al₂O₃–SiO₂–CaO Inclusions During Continuous Casting of Si‐Killed Spring Steel

Tailoring Low‐Alloyed Cryogenic Steel Strong and Tough Introduces Fine‐Grained Equiaxed Ferrite by Intercritical Subquenching

Study on MnS Inclusion Aggregation along Continuous Casting Slab Thickness of Medium Carbon Structural Steel

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Effect of Cerium on the Microstructure and Inclusion Evolution of C-Mn Cryogenic Vessel Steels

Cited by 8 publications

References 29 publications

Evolution Mechanism of MgO–Al2O3–SiO2–CaO Inclusions During Continuous Casting of Si‐Killed Spring Steel

Evolution Mechanism of MgO–Al2O3–SiO2–CaO Inclusions During Continuous Casting of Si‐Killed Spring Steel

Tailoring Low‐Alloyed Cryogenic Steel Strong and Tough Introduces Fine‐Grained Equiaxed Ferrite by Intercritical Subquenching

Study on MnS Inclusion Aggregation along Continuous Casting Slab Thickness of Medium Carbon Structural Steel

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Evolution Mechanism of MgO–Al₂O₃–SiO₂–CaO Inclusions During Continuous Casting of Si‐Killed Spring Steel

Evolution Mechanism of MgO–Al₂O₃–SiO₂–CaO Inclusions During Continuous Casting of Si‐Killed Spring Steel