Crystallography of graphite spheroids in cast iron

Theuwissen, Koenraad; Laffont, Lydia; Véron, M.; Lacaze, Jacques

doi:10.1080/13640461.2016.1142233

Cited by 6 publications

(7 citation statements)

References 18 publications

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“…Based on previous observations [9] and literature review, it has already been pointed out that nuclei may have a rounded shape and be amorphous [6]. In the present study, the rounded nucleus seen in Fig.…”

Section: Discussionsupporting

confidence: 73%

Analysis of Nuclei in a Heavy-Section Nodular Iron Casting

Celis

Domengès²,

Hug

et al. 2018

MSF

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The microstructure of heavy section nodular graphite cast irons often presents a bimodal distribution of nodule size associated with so-called primary and secondary graphite nucleation. It has been found that the nuclei in both types of nodules consist mainly in magnesium sulphide. However, nuclei in primary nodules contain some traces of calcium and are thus related with the inoculation treatment. On the contrary, nuclei in secondary nodules do not contain any element that could be associated to inoculation. It is suggested they form in the late stage of the eutectic reaction as a result of microsegregation build-up in magnesium and sulphur.

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Section: Discussionsupporting

confidence: 73%

Analysis of Nuclei in a Heavy-Section Nodular Iron Casting

Celis

Domengès²,

Hug

et al. 2018

MSF

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“…A last note concerning Figure 2 is that graphite developed as sectors right at the surface of the nucleus, but no epitaxy could be found between any of the dark crystalline precipitates and the graphite around. 17 This suggests that graphite could certainly nucleate on any heterogeneous substrate and that the most important step in the nodularizing process is graphite growth as already pointed out by various authors. 10,11 This will be further elaborated in the next section.…”

Section: Graphite Nucleationmentioning

confidence: 74%

“…Figure 2 shows the nucleus of a graphite spheroid found in an industrial nodular cast iron. 17 This nucleus consists mainly of (Ca,Mg)S, but is amorphous and was certainly liquid when graphite nucleated. As mentioned above, several small particles of crystalline phases can be seen at the periphery of this nucleus.…”

Section: Graphite Nucleationmentioning

confidence: 99%

Trace Elements and Graphite Shape Degeneracy in Nodular Graphite Cast Irons

Lacaze

2016

Inter Metalcast

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Graphite degeneracy in spheroidal graphite cast iron is a common issue faced by foundries. It is generally associated with the presence of so-called poisoning elements and may in some cases be suppressed by the addition of other elements. Mastering these additions is not simple in practice since industrial alloys do generally contain many elements that can affect graphite shape even when present at low or trace levels. In this work, trace and low-level elements are considered in relation with three steps of microstructure formation: (1) nucleation of graphite; (2) growth of graphite; and (3) solid-state transformations.

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“…The formation of white cast iron was eluded, injection of magnesium additions makes graphite nodular in shape and ferrosilicon promotes graphitization during solidification. As compared to flaky graphite in grey cast iron, spheroidal graphite does not weaken the matrix significantly; hence, the mechanical properties are of better quality compared to the grey iron [12].…”

Section: Materials Melting Processesmentioning

confidence: 97%

Spheroidal graphite iron production of furnace roof hangers

et al. 2021

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The wire rod mill of the Ajaokuta Steel Company Limited produces coils, wire rods and re-bars of different sizes. Without the furnace hangers, it will be difficult for the mill to continue to operate. This paper describes the production of furnace roof hangers that are required for re-heating furnace using the spheroidal graphite iron (SGI), highlighting the sand-casting process, charge calculation, and the chemical compositions. The facilities within the foundry shop of the steel company are used to produce furnace roof hangers. The available materials used for the casting of the hangers are the pig iron, scrap ends, foundry returns and magnesium. The process of production was performed through the reheating furnace for the heating of 120 m x 120 m x 120 m billets. One ton induction furnace of low frequency was used as the melting vessel. Also, 6 kg of magnesium was introduced in the ladle before the liquid metal was teemed into it. A Spectro analytical instrument was used to determine the chemical compositions of the materials before and after the casting processes. The analysis of the chemical compositions of produced sample of SGI are presented and discussed.

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Crystallography of graphite spheroids in cast iron

Cited by 6 publications

References 18 publications

Analysis of Nuclei in a Heavy-Section Nodular Iron Casting

Analysis of Nuclei in a Heavy-Section Nodular Iron Casting

Trace Elements and Graphite Shape Degeneracy in Nodular Graphite Cast Irons

Spheroidal graphite iron production of furnace roof hangers

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