Inclusions modification by rare earth in steel and the resulting properties: A review

Wang, Xiaoqiang; Wu, Zhiwei Steven; Li, Bing; Chen, Wenxiong; Zhang, Jun; Mao, Jian

doi:10.1016/j.jre.2023.04.015

Cited by 15 publications

(6 citation statements)

References 152 publications

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“…The modification of inclusions by rare earth elements effectively reduces the size of the inclusions and reduces the stress concentration between the inclusions and the matrix, which helps to increase the plasticity of the material. In addition, the Cottrell atmosphere formed by the aggregation of carbon atoms facilitates the expansion of the Lüders strain region to increase the ductile shape of the material [28].…”

Section: Discussionmentioning

confidence: 99%

“…It indicates that the addition of rare earths can effectively optimize the ferrite and pearlite. It has been observed that the mechanism of refinement by rare earths is primarily explained by the fact that rare earth inclusions act as heterogeneous nucleation sites during solidification, which can effectively refine the austenite grain size (PAGS) [28,29]. In order to verify the organization of the materials even further, the EBSD data with and without rare earth materials were compared (Figure 2).…”

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: Discussionmentioning

confidence: 99%

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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“…In the lab, the evolution was simple, such as following Al 2 O 3 →CeAl 11 O 18 →CeAlO 3 →Ce 2 O 3 in labs. [11][12][13] And in industry, the evolution was complex, such as following CaO-Al 2 O 3 → (Ca-Ce-S-O) + (Al-Ca-O-Ce) and following MnS + Al 2 O 3 -MnS → MnS + Ce-Al-O-MnS + Ce-O-MnS → MnS + Ce-S-MnS + Ce-S + Ce-O-S-MnS + Ce-O-S → Ce-S + Ce-O-S. [14][15] As known, a key of research value was industrial application. Considering complexity of actual inclusions in steelmaking process, it was meaningful to research the formation of Ce-based complex inclusions.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of cerium-based inclusion formation and influence on impact toughness in industrial Al-killed steel

Zhang,

Zhi,

Song

et al. 2024

Ironmaking & Steelmaking: Processes, Products and Applicati

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Mechanism of cerium-based inclusion formation and influence on impact toughness were researched in industrial Al-killed steel. In the final product, actual inclusions were complex, consisting of Al-O-Ce (Ce-poor), Al-O-Ce (Ce-rich), Al-O-Ce-S(Al-poor) and S-Ca (Mn-rich) from inside to outside. Results of thermodynamic balance calculation were completely inconsistent with the actual inclusions. Considering decomposing or disappearing of formed inclusions in steel difficult, new computing results showed that inclusions were formed by firstly Al2O3 (exist in molten steel before adding Ce), AlCeO3, Ce2O2S, CaS, Ca (Mn)S and MnS in turn, in better agreement with the actual inclusions. Outside of the actual inclusions, Ce2O2S and CaS had a smaller disregistry with ferrite, which could offer effective nucleation sites. And small inclusion was surrounded in a grain and bigger inclusion was surrounded in two grains at least. Microstructures were observed that grains with Ce were finer than grains without Ce. Moreover, V-notch impact toughness of samples was tested at 0 and −60°C, respectively. Compared with samples without Ce, the values of impact toughness were increased by 161% at 0°C and 225% at −60°C, respectively. And fracture surface with Ce had more and finer dimples and finer cleavages than that without Ce.

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“…Rare earth resources are abundant in China, and they are widely used to modify inclusions and enhance steel cleanliness. − Wang et al demonstrated that 0.021% rare earth effectively reduced the number density and the area rate of inclusions in stainless steel, and the modified RE x O y and RE 2 O 2 inclusions inhibited the anodic activity and displayed a good repassivation capability. Dong et al found that 0.0047% rare-earth-modified Al 2 O 3 •CaO inclusions into REAlO 3 •CaO inclusions in high strength low alloy (HSLA) steel, and the corrosion rate of which could exceed the weathering steel in the same corrosive solution.…”

Section: Introductionmentioning

confidence: 99%

Effect of Cerium on Inclusion Evolution and Pitting Corrosion of Nb-Microalloyed Steel

Zhang,

Yu,

Zhang

et al. 2024

Langmuir

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Nb-microalloyed steels are widely used in construction engineering fields due to their excellent mechanical properties, but they face serious corrosion problems in service environments. Pitting corrosion is the severest form of corrosion, and the types of inclusions are the leading cause to induce pitting corrosion. A new strategy is proposed to enhance the corrosion resistance of steels by achieving a beneficial transformation of inclusions with Ce treatment. In this paper, two types of Nbmicroalloyed steels (0% Ce and 0.0058% Ce steel) were prepared to study the modification effect on inclusions in industrial production. The spherical CaS•C 12 A 7 inclusions were modified to smaller ellipsoidal Ce 2 O 2 S inclusions, and the proportion of inclusions (0−2 μm) increased significantly from 27 to 66%, while large inclusions (>6 μm) disappeared. A kinetic model of inclusion evolution was established. The results of electrochemical tests indicated that the corrosion potential was positively shifted, and the corrosion current was reduced after Ce treatment. Additionally, the number of defects in the passivation film was decreased, and the corrosion resistance of the steel was significantly improved. The addition of Ce changed the types of inclusions and reduced the number of pitting nucleation points, which led to a remarkable reduction in the number and size of pitting pits. The mechanism of pitting corrosion induced by different types of inclusions was further investigated, and a pitting corrosion model was modeled based on the immersion experiments. Research results provide theoretical support for enhancing the corrosion resistance of steel.

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Inclusions modification by rare earth in steel and the resulting properties: A review

Cited by 15 publications

References 152 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

Mechanism of cerium-based inclusion formation and influence on impact toughness in industrial Al-killed steel

Effect of Cerium on Inclusion Evolution and Pitting Corrosion of Nb-Microalloyed Steel

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