Investigation of Dendrite Coarsening in Complex Shaped Lamellar Graphite Iron Castings

Svidró, Péter; Diószegi, Attila; Pour, Mohsen Saffari; Jönsson, Pär G.

doi:10.3390/met7070244

Cited by 4 publications

(3 citation statements)

References 15 publications

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“…In this work, the amount of latent heat release due to solidification was related to the solid fraction curves, seen in Figure 4, for the studied alloys. These curves were calculated from the registered experimental cooling curves by using the Fourier thermal analysis method [16,17]. The latent heat of solidification was considered equal to 240 kJ/kg for all studied alloys [18].…”

Section: Simulation Model and Assumptionsmentioning

confidence: 99%

Strength Prediction for Pearlitic Lamellar Graphite Iron: Model Validation

Fourlakidis

Belov

Diószegi

2018

Metals

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The present work provides validation of the ultimate tensile strength computational models, based on full-scale lamellar graphite iron casting process simulation, against previously obtained experimental data. Microstructure models have been combined with modified Griffith and Hall–Petch equations, and incorporated into casting simulation software, to enable the strength prediction for four pearlitic lamellar cast iron alloys with various carbon contents. The results show that the developed models can be successfully applied within the strength prediction methodology along with the simulation tools, for a wide range of carbon contents and for different solidification rates typical for both thin- and thick-walled complex-shaped iron castings.

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Section: Simulation Model and Assumptionsmentioning

confidence: 99%

Strength Prediction for Pearlitic Lamellar Graphite Iron: Model Validation

Fourlakidis

Belov

Diószegi

2018

Metals

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“…Investigators have also found that zones experiencing penetration of metal into the sand mold, or conversely, penetration of mold gases into the casting, tend to contain locally coarser dendrites. 69 This highlights that the dendrite coarsening process contributes to growth of interdendritic channels and thereby facilitates transfer of fluids between metal and mold. The impact of the coarsening process on the interdendritic permeability is well-recognized for other technical alloys.…”

Section: Effects Of Dendrite Microstructurementioning

confidence: 97%

A Review of Dendritic Austenite in Cast Irons

Domeij,

Diószegi

2024

Inter Metalcast

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Solidification of cast irons usually involves dendritic growth of austenite. This article presents a literature survey about the dendrites in cast irons, their consequences and how they may be manipulated. The literature review is supplemented with relevant micrographs from our research. While austenite usually transforms into ferrite or pearlite, the dendrites limit where liquid flows, where eutectic grows, and where segregated elements go. The amount and shape of dendrites show correlations with tensile strength in pearlitic gray and compacted graphite irons. There are also indications that a coarse dendrite grain structure may be beneficial to tensile strength. The dendrite grain structure depends on melting process parameters and shows sensitivity to melt treatment. The evolution of scale of dendrite arms and their spacing under isothermal condition is by now fairly well-understood; however, work remains to better understand its evolution during cooling and its interaction with the eutectic. The amount and shape of dendrites are less understood in irons of near-eutectic and hypereutectic composition, in particular mixtures of dendrites of distinct scales, associated with regions of distinct graphite morphology. While significant advances have been made in recent years, the role and control of dendrites remain a relatively unexplored area of research with potential to improve production and properties of cast irons.

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“…It should be noted that there is another important indicator of the course of inoculation, which, however, in practice is the most difficult to assess, namely: the characteristics of changes in the formation of primary austenitic dendrites. Primary austenite is the least investigated microstructural component of grey cast iron [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. It is the first phase to be nucleated in the liquid metal and it grows in a dendritic manner, followed by growth of the eutectic phase.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Undercooling ΔT on the Structure and Tensile Strength of Grey Cast Iron

et al. 2021

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Inoculation of cast iron has become a commonly used metallurgical process, which is carried out in a foundry in order to improve the mechanical properties of utility alloys. It consists in changing the physicochemical state of the melted alloy. This change is caused by the introduction of cast iron with a low ability to nucleate graphite, shortly before pouring a small mass of the substance—an inoculant that increases the number of active nuclei. It is also justified that the literature often connects an increase in the tensile strength UTS of the inoculated grey cast iron, with changes in the characteristics of the particles of graphite. However, in strongly hypoeutectic cast iron, in which a large number of primary austenite grains crystallize, the interdendritic distribution of graphite is usually the result. It also follows that the nature of the graphite precipitates is determined by the mutual relations between the interfacial distances in eutectic grains and the interdendritic distances in the grains of primary austenite occurring in the Fe–C alloys. The article presents the influence of the inoculant on the characteristics of the precipitation of primary austenite grains in relation to the sulphur content in grey cast iron with flake graphite. The study also showed that primary grains in grey cast iron have a great influence on mechanical properties, such as the tensile strength UTS. In this case, the key is to know the value of the degree of undercooling ΔT. The type of inoculant used affects the ΔT value. The study related the number of N primary austenite grains with the degree of undercooling ΔT and the tensile strength UTS with the number of primary austenite N grains.

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Investigation of Dendrite Coarsening in Complex Shaped Lamellar Graphite Iron Castings

Cited by 4 publications

References 15 publications

Strength Prediction for Pearlitic Lamellar Graphite Iron: Model Validation

Strength Prediction for Pearlitic Lamellar Graphite Iron: Model Validation

A Review of Dendritic Austenite in Cast Irons

The Influence of Undercooling ΔT on the Structure and Tensile Strength of Grey Cast Iron

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