Abrupt Casting Failures Due to Sub Entry Nozzle Clogging in Calcium Treated Aluminum Killed Steel

Kumar, Sanjeev; Keshari, K. K.; Deva, A.; Singh, Rajeev Kumar; Roy, S.; Kumar, Vikash; Toppo, S.; Kumar, Abhishek; Pradhan, N.

doi:10.1007/s11668-022-01569-5

Cited by 7 publications

(3 citation statements)

References 19 publications

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“…As the Ca treatment progress continues, the C x A y inclusions evolved in this order: CA 6 → CA 2 → C 12 A 7 . Eventually, the C x A y were transformed into liquid inclusions (C 12 A 7 ), which facilitated the smooth casting of the molten steel. − With the decrease of molten steel temperature, the thickness of CaS in the outer layer of the inclusions increased. This was due to the fact that, after the Ca treatment, excess calcium reacted with S to form CaS and adhered to the surface of the inclusions (as shown in eq 13) .…”

Section: Resultsmentioning

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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Section: Resultsmentioning

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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“…Domizzi et al 34) suggested that it was not necessary to reach costly extra low values of sulfur (≤ 0.002%) to obtain a good HIC resistance if there was no elongated MnS in steel. However, under the conditions of ideal modification of MnS inclusions, the oxygen content in steel was related to the sulfur content, which could be deduced by combining equation (1) and equation ( 2): 17 The mass ratio of T.Ca/T.O in sample A and sample B met the equation ( 1), illustrating that C 12 A 7 could be generated in molten steel.…”

Section: Figure 13mentioning

confidence: 95%

“…Many researchers [14][15][16] have found that MnS inclusions could be modified into high melting point sulfides which were not as readily deformable by adding elements into steel, such as calcium, and rare earth. As calcium has strong affinity with oxygen and sulfur, CaS and even CaO inclusions will be produced if excessive calcium is fed into molten steel, which may cause severe clogging of nozzle or the shutdown of continuous casting 17,18) . The MnS inclusions will not be completely modified after solidification of molten steel due to the insufficient calcium addition.…”

Section: Introductionmentioning

confidence: 99%

Cause of Bending Fracture and Control of Inclusions in High-strength Fasteners Made of Al-bearing High Carbon Steel

Zhang,

Long,

Cheng

et al. 2023

ISIJ Int.

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In this paper, the cause of bending fracture of high-strength fasteners after electroplating and the effect of T.Ca, T.O, and T.S contents in Al-bearing high carbon steel on the type, size, and shape of inclusions were studied. The fracture surface of fastener exhibited stepwise cracks and a lot of intergranular facets associated with ductile tearing, which were typical of hydrogen embrittlement. The agminated elongated MnS inclusions in the center of fasteners could aggravate the susceptibility of hydrogen embrittlement. Thermodynamic calculation showed that the ideal modification of MnS inclusions needed to meet the conditions that the inclusions in molten steel before solidification should be C 12 A 7 , and the mass ratio of CaS/MnS at the end of solidification was 23.7. Based on the above conditions, the quantitative relationships between the contents of T.

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Nanoindentation Hardness and Modulus of Al2O3–SiO2–CaO and MnO–SiO2–FeO Inclusions in Iron

Slagter,

Setyadji,

Vogt

et al. 2024

Metall Mater Trans A

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Oxide inclusions appear in steel as a subproduct of steelmaking. These are generally detrimental to alloy properties; however, variations exist in the extent to which different inclusions are harmful because their properties vary as a function of their chemical composition. We use nanoindentation to measure the local elastic modulus and hardness of individual oxide particles, produced by precipitation within liquid iron, that belong to the systems Al2O3–SiO2–CaO and MnO–SiO2–FeO. Measured inclusion hardness values are typically in the range of 8 to 13 GPa and can reach 26 GPa for alumina-rich inclusions. Calcium aluminates rich in alumina are significantly stiffer than iron, with elastic moduli that can reach 350 GPa. On the contrary, calcium aluminates that are expected as a result of successful calcium treatment (i.e., with less than about 80 wt pct Al2O3 content) have elastic moduli below that of iron. This is also the case for the wide range of calcium aluminosilicates and of manganese silicates studied here. In addition, silicates containing about 70 to 80 wt pct MnO are observed to have a fine multiphase structure and an elastic modulus of ≈ 180 GPa. Those inclusions thus emerge as possible candidates if one aims to minimise, in loaded steel, stress concentrations associated with matrix-inclusion elastic mismatch.

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Abrupt Casting Failures Due to Sub Entry Nozzle Clogging in Calcium Treated Aluminum Killed Steel

Cited by 7 publications

References 19 publications

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

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

Cause of Bending Fracture and Control of Inclusions in High-strength Fasteners Made of Al-bearing High Carbon Steel

Nanoindentation Hardness and Modulus of Al2O3–SiO2–CaO and MnO–SiO2–FeO Inclusions in Iron

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