The Oxide Produced by Addition of Aluminium to Molten Iron

Watanabe, Shunroku; Takano, Katutoshi; Moriya, Kaoru; Tu, Yasuhide; Shiroishi, Yutaka

doi:10.2355/tetsutohagane1955.65.3_383

Cited by 4 publications

(7 citation statements)

References 3 publications

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“…[1][2][3][4][5][6][7] As was reported in the latest report, 2) the d and g-alumina were observed as secondary inclusions formed during cooling of iron. However, the d, g, k, and qaluminas are not stable at steelmaking temperatures and are metastable at ordinary temperatures, whilst the a-alumina is stable.…”

Section: Introductionsupporting

confidence: 53%

“…(3-1)-(3-4), (3)(4)(5)(6), and (3-13)-(3-21) are shown in Table 1. Table 1 shows that a, g and liquid-alumina all nucleate at a similar rate and the rate of d-alumina is the largest in the case of liquid iron with initial contents of 0.1 mass% Al and 0.0200 mass% O.…”

Section: Modified Classical Homogeneous Nucleationmentioning

confidence: 99%

“…The s Fe-i calculated from the molar enthalpies of aluminas, H i°, 14) using Eqs. (3-10)- (3)(4)(5)(6)(7)(8)(9)(10)(11)(12) are shown as functions of temperature in Fig. 3.…”

Section: Classical Homogeneous Nucleation Theorymentioning

confidence: 99%

“…From Eqs. (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)-(3-21), the s°F e-i s, which depend on oxygen content and curvature of alumina nucleus, can be calculated.…”

Section: Modified Classical Homogeneous Nucleationmentioning

confidence: 99%

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Thermodynamic Analysis on Metastable Alumina Formation in Aluminum Deoxidized Iron Based on Ostwald's Step Rule and Classical Homogeneous Nucleation Theories.

Wasai

Mukai

2002

ISIJ International

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A mechanism for the formation of unstable alumina (d, g, and k-alumina) in Al-deoxidized iron has been investigated on the basis of Ostwald's Step Rule and two homogeneous nucleation theories. The two homogeneous nucleation theories include a simplified theory in widespred use and the other is a modified theory in which the Gibbs free energy change of the parent iron phase is taken into consideration.Comparison of the chemical potential of various aluminas from the standpoint of the Ostwald'sStep Rule showed that the unstable alumina could form from the liquid iron alloy supersaturated with oxygen. Moreover, the rule revealed that there is a possibility of liquid alumina formation. The two homogeneous nucleation theories also proved the possibility of the formation of unstable and liquid alumina. The latter nucleation theory indicated the easier nucleation of liquid and unstable aluminas than that for a-alumina from the liquid iron containing oxygen contents in excess of the critical value of nucleation at 1 873 K. In contrast, nucleation was rare for oxygen contents less than the critical point at 1 873 K. However, unstable alumina can be formed during cooling and solidification since the oxygen contents of the critical point decreases with temperature decrease. When iron solidifies whilst in the supercooled condition, the nucleation rates of unstable and liquid alumina can be accelerated as a result of the oxygen enrichment at the solidifying front. The authors propose a mechanism of the network-like or coral like inclusion formation by taking into consideration of the liquid alumina formation.

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Section: Introductionsupporting

confidence: 53%

Section: Modified Classical Homogeneous Nucleationmentioning

confidence: 99%

“…The s Fe-i calculated from the molar enthalpies of aluminas, H i°, 14) using Eqs. (3-10)- (3)(4)(5)(6)(7)(8)(9)(10)(11)(12) are shown as functions of temperature in Fig. 3.…”

Section: Classical Homogeneous Nucleation Theorymentioning

confidence: 99%

“…From Eqs. (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)-(3-21), the s°F e-i s, which depend on oxygen content and curvature of alumina nucleus, can be calculated.…”

Section: Modified Classical Homogeneous Nucleationmentioning

confidence: 99%

See 2 more Smart Citations

Thermodynamic Analysis on Metastable Alumina Formation in Aluminum Deoxidized Iron Based on Ostwald's Step Rule and Classical Homogeneous Nucleation Theories.

Wasai

Mukai

2002

ISIJ International

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“…(2) The presence of g, d, q and k-alumina inclusions has been reported [6][7][8][9][10] in iron solidified immediately after aluminum-deoxidation. The g, d, q and k-alumina are unstable at steelmaking temperatures, whereas the a-alumina is a stable crystal phase.…”

Section: Introductionmentioning

confidence: 99%

Observation of Inclusion in Aluminum Deoxidized Iron.

2002

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Aluminum-deoxidized iron at 1 873 K was solidified at 3 different cooling speed; (1) the ultra-rapid cooling of iron using twin rollers, (2) the quenching of iron into copper mold, and (3) the quenching of the iron-bearing crucible in a water bath; the most rapid cooling rate achieved with (1), which was probably about 10 5 K/s, followed (2) and (3). Dendritic, maple-like, polygonal, network-like, coral-like and spherical inclusions were observed in the samples. The dendritic, maple-like and polygonal inclusions varied in size from several tens to a few mm and were classified as primary inclusions since their sizes were independent of cooling speed. However, the network-like and coral-like inclusions (in the sample cooled ultra-rapidly and quenched into copper mold), and spherical inclusions were classified as secondary inclusions since they decreased in size with increased cooling speed. A few large spherical inclusions, which would be primary inclusions, were also present.The analysis of the electronic diffraction of the inclusions established that the a, g, d-alumina were present as secondary inclusions. An amorphous silica spherical inclusion was also observed.

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Inclusions in Iron Ingots Deoxidized with Aluminum and Solidified Unidirectionally

Aritomi

Gunji

1981

Trans. JIM

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The Oxide Produced by Addition of Aluminium to Molten Iron

Cited by 4 publications

References 3 publications

Thermodynamic Analysis on Metastable Alumina Formation in Aluminum Deoxidized Iron Based on Ostwald's Step Rule and Classical Homogeneous Nucleation Theories.

Thermodynamic Analysis on Metastable Alumina Formation in Aluminum Deoxidized Iron Based on Ostwald's Step Rule and Classical Homogeneous Nucleation Theories.

Observation of Inclusion in Aluminum Deoxidized Iron.

Inclusions in Iron Ingots Deoxidized with Aluminum and Solidified Unidirectionally

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