Graphite nodule count and size distribution in thin-walled ductile cast iron

Pedersen, Karl Martin; Tiedje, Niels Skat

doi:10.1016/j.matchar.2007.09.001

Cited by 65 publications

(45 citation statements)

References 14 publications

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“…[26][27][28] This study characterizes the graphite evolution using the concept of nodularity explained in ISO 16112:2006(E) [29] and E2567 -16a from ASTM, [30] the standards with a wider application among cast iron users and industry. According to both standards, microstructural features smaller than 10 lm are considered as microporosities, defects due to sample preparation or particles that should be excluded from graphite analysis.…”

Section: E Graphite Characterizationmentioning

confidence: 99%

New Experimental Technique for Nodularity and Mg Fading Control in Compacted Graphite Iron Production on Laboratory Scale

Hernando

Domeij

González

et al. 2017

Metall Mater Trans A

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The narrow production window for compacted graphite iron material (CGI) drastically reduces the possibilities to produce it in small batches outside an industrial environment. This fact hinders laboratory-scale investigations on CGI solidification. This work presents a solution to that issue by introducing an experimental technique to produce graphitic cast iron of the main three families. Samples of a base hypereutectic spheroidal graphite iron (SGI) were re-melted in a resistance furnace under Ar atmosphere. Varying the holding time at 1723 K (1450°C), graphitic irons ranging from spheroidal to lamellar were produced. Characterization of the graphite morphology evolution, in terms of nodularity as a function of holding time, is presented. The nodularity decay for the SGI region suggests a linear correlation with the holding time. In the CGI region, nodularity deterioration shows a slower rate, concluding with the sudden appearance of lamellar graphite. The fading process of magnesium, showing agreement with previous researchers, is described by means of empirical relations as a function of holding time and nodularity. The results on nodularity fade and number of nodules per unit area fade suggest that both phenomena occur simultaneously during the fading process of magnesium.

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Section: E Graphite Characterizationmentioning

confidence: 99%

New Experimental Technique for Nodularity and Mg Fading Control in Compacted Graphite Iron Production on Laboratory Scale

Hernando

Domeij

González

et al. 2017

Metall Mater Trans A

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“…Note that interaction DG could "skew" the significant effect of interactions AC+BE+DG, as high casting temperatures favour metastable solidification and could possibly promote the presence of solidification micro-shrinkages in segregated zones. These micro-cavities may "confuse" the image analyzer with graphite thus leading to misleading results (Pedersen and Tiedje, 2008). Figure 4 shows an example of these microcavities, obtained in test No.…”

Section: Discussionmentioning

confidence: 99%

Optimización microestructural de fundiciones grises dúctiles no aleadas, con matriz ferrítica, empleadas en la fabricación de bujes de aerogeneradores

2018

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ABSTRACT:The aim of this work was the microstructural optimization of cast irons with nodular graphite for the manufacture of wind turbine hubs, paying preferential attention to the geometry and distribution of graphite spheroids to ensure the required mechanical properties for this application. The target was pursued based upon microstructure-properties correlation, in an environment of great competitiveness and exigency marked by current international standards. The methodology followed consisted of the generation of knowledge from tailor-made industrial castings, followed by the analysis of their microstructures, in order to extract valuable conclusions for the production process through the use of statistical analysis. The approach method employed was a Fractional Design of Experiments (DOE) with 7 factors, 16 experiments and resolution IV. The samples from each experiment were cubes of identical geometry, and designed to match a surface-to-volume module equal to 4 cm (1.57 in) found as the highest values in real hubs of 3 MW power wind turbines. It is concluded that the use of nodulizers with traces of lanthanum favour the reduction of the volume fraction of pearlite, although La has proved not to promote the spherical shape of primary graphite. The negative effect of preinoculants containing SiC on the spheroidal morphology of graphite has also been verified, and also that lowMn bearing scrap favours graphite formation and the reduction of the volume fraction of pearlite, in spite of being a carbide forming element. The whitening effect of Mn was minimized with low carbon equivalent melts. RESUMEN:Optimización microestructural de fundiciones grises dúctiles no aleadas, con matriz ferrítica, empleadas en la fabricación de bujes de aerogeneradores. El objetivo de este trabajo fue la optimización microestructural de fundiciones grises con grafito esferoidal y matriz ferrítica, empleadas en la fabricación de bujes de aerogeneradores, prestando una especial atención a la geometría y distribución de los esferoides de grafito para asegurar el cumplimiento de las propiedades mecánicas requeridas para esta aplicación. En un entorno de gran competitividad y exigencia, marcado por los estándares internacionales que establecen las propiedades mecánicas mínimas que deben cumplir los materiales empleados, el cumplimiento de este objetivo se llevó a cabo correlacionando microestructura y propiedades. Para ello, la metodología de investigación consistió en la generación de conocimiento a partir de coladas industriales "a medida", seguido de un análisis de la microestructura, con el fin de extraer conclusiones importantes, de aplicación práctica en el proceso de fabricación, mediante el 2 • J. Asensio-Lozano et al.Revista de Metalurgia 54(2), April-June 2018, e118. ISSN-L: 0034-8570. https://doi.org/10.3989/revmetalm.118 empleo de técnicas estadísticas. La herramienta estadística empleada fue un Diseño de Experimentos Fraccional (DOE), con 7 factores, 16 experimentos y resolución IV. Las muestras empleadas en cada experim...

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“…Farklı aşılayıcı kullanılarak yapılan çalışmalarda; çeşidine bağlı olarak değişmekle birlikte aşılayıcı ilavesi ile döküm içyapısında oluşan kürelerin daha düzgün yapıda oluşarak % küresellik değerlerinin arttığı, ortalama küre çapının azalarak, birim alana düşen küre sayılarının arttığı tespit edilmiştir [17,19].…”

Section: Mekanik Test İncelemeleriunclassified

GGG-60 Küresel Grafi̇tli̇ Dökme Demi̇r Üreti̇mi̇nde Aşilayici Türü Ve Mi̇ktarinin İçyapi Ve Mekani̇k Özelli̇klere Etki̇si̇ni̇n İncelenmesi̇

Karadeniz

Çolak

Barutçu

2016

Ömer Halisdemir Üniversitesi Mühendislik Bilimleri Dergisi

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ÖZKGDD ailesinden GGG-60, yüksek aşınma direnci ve mukavemet değerlerine sahip olabilen bir metaldir. Ayrıca döküm yöntemleriyle şekillendirildiklerinden uygun maliyetlerde ve seri bir şekilde iş parçaları elde edilebilmektedir. Döküm yöntemleriyle şekil vermede ürün içyapıları, dolayısıyla da mekanik özellikleri üzerinde katılaşma aşaması çok etkilidir. Homojen ince taneli grafitlerden oluşan içyapı üstün mekanik özellikleri nedeniyle istenilen bir ürün içyapısıdır. KGDD malzemelerin katılaşma aşamasında aşılama işlemi ve aşılayıcı çeşitleri istenilen mekanik özellikleri elde etmek için en önemli faktördür. Ticari üretim yapan dökümhaneler arasında piyasada kullanım bulan çok farklı aşılayıcı malzemeler bulunmaktadır. Ayrıca bunların ilave miktarları ve yöntemleri dökümhaneye bağlı farklılık göstermektedir. Bu sebeple çalışmada piyasada en yaygın kullanım bulan 3 farklı aşılayıcı ve 2 çeşit aşılayıcı farklı oranlarda kullanılarak GGG-60 malzeme ile döküm deneyleri yapılmıştır. Böylece aşılayıcı türü ve miktarına bağlı olarak üretilen malzemenin içyapı ve mekanik özellikleri araştırılmıştır. İçyapı değerlendirmeleri optik mikroskop, mekanik özellikler ise çekme dayanımı ve sertlik değerleri sonuçları olarak sunulmuştur.Anahtar Kelimeler: Küresel grafitli dökme demir, aşılayıcı, GGG-60, mikro yapı, mekanik test INVESTIGATION OF IMPACT OF AMOUNT AND TYPE OF INOCULANTS ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF GGG60 SPHEROIDAL GRAPHITE CAST IRONS ABSTRACTA ductile iron metal GGG-60 has a major abrasion resistance and strength value. In addition, since they can be formed by casting methods, parts can be obtained rapidly and cost effectively. The solidification step has an important impact on products internal structure and thereby on the mechanical properties in giving form by casting methods. Because of its excellent mechanical properties, the microstructure consisted of homogeneous fine-grained graphite is a desired product microstructure. The most important factors in solidification phase of ductile irons are inoculation and inoculant types to achieve the desired mechanical properties. Among the commercial foundries, many different inoculant materials are found use in the market. As well as their addition amounts and methods varies depending on the foundry. Therefore, in this study, the most commonly used three different types of inoculants, and different ratios of two types of inoculants were used for GGG-60 material casting experiments. Thus, the effects of type and amount of inoculant on microstructure and mechanical properties of the material were investigated. Internal structure evaluations are presented as optical microscope data, and mechanical properties are presented as data of tensile strength and hardness results.

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Graphite nodule count and size distribution in thin-walled ductile cast iron

Cited by 65 publications

References 14 publications

New Experimental Technique for Nodularity and Mg Fading Control in Compacted Graphite Iron Production on Laboratory Scale

New Experimental Technique for Nodularity and Mg Fading Control in Compacted Graphite Iron Production on Laboratory Scale

Optimización microestructural de fundiciones grises dúctiles no aleadas, con matriz ferrítica, empleadas en la fabricación de bujes de aerogeneradores

GGG-60 Küresel Grafi̇tli̇ Dökme Demi̇r Üreti̇mi̇nde Aşilayici Türü Ve Mi̇ktarinin İçyapi Ve Mekani̇k Özelli̇klere Etki̇si̇ni̇n İncelenmesi̇

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