Relationship Between Inoculants and the Morphologies of MnS and Graphite in Gray Cast Iron

Muhmond, Haji Muhammad; Fredriksson, Hasse

doi:10.1007/s11663-012-9768-6

Cited by 35 publications

(17 citation statements)

References 16 publications

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“…Their chemistry should then depend on microsegregation build-up and, in turn, their precipitation will affect the composition of the remaining liquid. That microsegregation during solidification can lead to formation of oxides or sulphides prone to trigger nucleation of graphite has often been mentioned in the literature and recently substantiated theoretically by Muhmond and Fredriksson [1]. However, this does not seem to have been challenged experimentally.…”

Section: Introductionmentioning

confidence: 89%

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: Introductionmentioning

confidence: 89%

Analysis of Nuclei in a Heavy-Section Nodular Iron Casting

Celis

Domengès²,

Hug

et al. 2018

MSF

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“…A Figura 1 mostra as matrizes das amostras inoculadas respectivamente com G-20, IM-22 e IMSR75, onde se presencia a distribuição de grafita tamanho 4 em sua forma lamelar do tipo A e C em matrizes essencialmente perliticas [6,7]. Entretanto o ferro fundido inoculado com IM-22 apresentou pequeno percentual de grafita de super-resfriamento (tipo D), também distribuídas finamente na matriz perlitica.…”

Section: Análise Microestruturalunclassified

Efeitos De Diferentes Inoculantes Nas Caracteristicas Microestruturais Do Ferro Fundido Cinzento Gg-25, Na Dureza E Vida Util Da Ferramenta De Usinagem

Martin¹,

Moreno²

2018

ABM Proceedings

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ResumoEste trabalho objetivou comparar, por meio de experimentos desenvolvidos em uma fundição, através da adição de três inoculantes diferentes (IM-22 com FeSi-Ba/Zr, G 20 com FeSi-Ba) e IMSR 75 com FeSi-Sr), para observar as características da vida util de ferramentas na usinabilidade das peças, microestrutura e propriedade mecânica. A metodologia da pesquisa se baseou em analisar principalmente pelo processo de fresamento o ferro fundido cinzento GG-25 inoculado diferentemente, denominado de acordo com a Norma DIN EN 1561. As formas de avaliação dos resultados terão como base uma análise quanto ao desgaste da ferramenta, acabamento superficial, análise microestrutural, composição química e propriedades mecânicas do material da peça. Os resultados mostraram que dentre os inoculantes aplicados o com Sulfeto de Estrôncio (SrS) apresentou-se mais estável termodinamicamente que as amostras inoculadas com os outros dois inoculantes, pois ele levou a uma variação da energia livre de Gibbs mais negativa e portanto mais favorável a formação de núcleos com raio crítico (rc) maiores, o que permitirá uma solidificação com nucleação heterogênea. Todavia o respectivo inoculante também foi mais eficiente na formação de uma microestrutura mais estável, com maiores quantidades de células eutéticas e vida útil do inserto mais longa quando usinado. Palavras-chave: Usinabilidade; Ferro fundido cinzento; Desgaste de ferramenta; Células eutéticas. EFFECTS OF DIFFERENT INOCULANTS IN THE MICROSTRUCTURAL CHARACTERISTICS OF GRAY CAST IRON GG-25, HARDNESS AND USEFUL LIFE OF THE MACHINE TOOL AbstractThis study aimed to compare, by means of experiments carried out in a melt, by addition of three different inoculants (IM-22 with Ba-Fe-Si/Zr, G-20 and Ba-FeSi) and IMSR 75 with FeSi-Sr), to observe the characteristics of the useful life of tools in the machinability of the pieces, microstructure and mechanical property. The search methodology is mainly based on analyzing the milling process gray cast iron GG-25 inoculated differently called according to DIN EN 1561. The forms of assessment of the results will be based on an analysis regarding the tool wear, microstructural analysis, chemical composition and mechanical property of the material. The results showed that among the inoculant applied to strontium was found to be more thermodynamically stable than the samples inoculated with the other two inoculants as it led to a more negative variation in Gibbs free energy and hence a more favorable training centers with critical radius (rc) higher, allowing a solidification with heterogeneous nucleation. However its inoculant was also more efficient in forming a more stable microstructure with larger amounts of eutectic cells and longer life of the insert when machined.

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“…Also Nb has been shown [13] to refine both dendrite and eutectic cell structure in grey cast iron. Recently Muhmond and Frederiksson [14,15] have contributed to a better understanding of the MnS formation mechanism in cast iron and its role in the nucleation of austenite as well as of graphite. In order for MnS to nucleate homogenously in the melt C Mn C S must be > 0.0126.…”

Section: Inoculationmentioning

confidence: 99%

A Contribution to the Understanding of the Combined Effect of Nitrogen and Boron in Grey Cast Iron

Strande¹,

Tiedje

Chen

2016

Inter Metalcast

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Inoculation is an essential part of controlling material properties in grey cast iron. Inoculation practice has for decades been based on the addition to the melt of small amounts of elements with strong affinity to O (and S) just before casting takes place. This method is proven -both in theory and in practice -to be effective in most cases. But it has the disadvantage that the nucleation effect fades away over time. Especially in heavy castings (slow cooling) this effect may cause non uniform and unacceptable material properties in some parts of the casting. Nitrogen is also known to influence grey iron microstructure. Both graphite flake formation and matrix formation are influenced. However, the obtained effects differ considerably between different reported investigations. This investigation deals with the combined effect of nitrogen and boron and how it in a simple way is possible to utilize this effect to enhance material properties in heavy grey iron castings. It is shown that controlled addition of nitrogen and boron in practice can be used to control microstructure of heavy grey iron castings. A plausible theory for formation of boron nitride nuclei effective for graphite growth is presented.

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Relationship Between Inoculants and the Morphologies of MnS and Graphite in Gray Cast Iron

Cited by 35 publications

References 16 publications

Analysis of Nuclei in a Heavy-Section Nodular Iron Casting

Analysis of Nuclei in a Heavy-Section Nodular Iron Casting

Efeitos De Diferentes Inoculantes Nas Caracteristicas Microestruturais Do Ferro Fundido Cinzento Gg-25, Na Dureza E Vida Util Da Ferramenta De Usinagem

A Contribution to the Understanding of the Combined Effect of Nitrogen and Boron in Grey Cast Iron

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