Effects of Number of Graphite Nodules on Fatigue Limit and Fracture Origins in Heavy Section Spheroidal Graphite Cast Iron

Shiraki, Naoto; Usui, Yuki; Kanno, Toshitake

doi:10.2320/matertrans.f-m2015841

Cited by 11 publications

(10 citation statements)

References 4 publications

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“…In order to validate the proposed model, further experimental data were taken from the literature [9][10][11]25,26,28,29,33 where mechanical and fatigue properties (load ratio equal to 0 or −1) of as-cast ferritic ductile cast irons with long solidification times have been investigated. These works reported the actual mechanical properties of the materials and the dimension of the intrinsic initiating defects.…”

Section: Fatigue Resistance Prediction Of As-cast Heavy Section Ducmentioning

confidence: 99%

“…In many works found in literature, [8][9][10][11][12] various types of solidification defects have been studied, in order to evaluate their influence on the static and fatigue resistance of the components. The ultimate tensile strength and the elongation at failure are lowered by solidification defects, while hardness and yield stress are less affected.…”

Section: Introductionmentioning

confidence: 99%

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Novel method for the fatigue strength assessment of heavy sections made by ductile cast iron in presence of solidification defects

Borsato

Ferro

Berto³

2018

Fatigue Fract Eng Mat Struct

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The fatigue strength of ferritic, pearlitic, and solution strengthened ferritic ductile irons taken from heavy sections and characterized by long solidification times has been assessed. Starting from the idea of Murakami and co‐workers, a new model for the prediction of the fatigue strength is proposed. It allows a sound fatigue assessment of the fatigue strength of as‐cast ductile irons containing solidification defects, such as low nodule count, exploded, chunky and spiky graphite, or microshrinkage porosities. The newly developed equation validated by means of an extensive benchmarking with data taken from the literature has shown a very high potential for applications to thick‐walled components.

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Section: Fatigue Resistance Prediction Of As-cast Heavy Section Ducmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Novel method for the fatigue strength assessment of heavy sections made by ductile cast iron in presence of solidification defects

Borsato

Ferro

Berto³

2018

Fatigue Fract Eng Mat Struct

View full text Add to dashboard Cite

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“…For instance, the sphericity and spatial distribution of nodules affect strength and toughness. Fatigue strength is influenced by count and diameter [10,11].…”

Section: Graphite Morphology and Microstructure Of Roll Core Before Amentioning

confidence: 99%

“…As a phase of the DCI, the graphite must have some changes during this heating process. For this objective, the morphological changes of spheroidal graphite under the continuous heating were observed by HM-350 high temperature metallographic microscope [11]. It illustrates that the transformation of pearlite into austenite after 1023 K has been very obvious.…”

Section: Graphite Morphology Analysis In the Bimetallic Bonding Intermentioning

confidence: 99%

Research on the Bonding Interface of High Speed Steel/Ductile Cast Iron Composite Roll Manufactured by an Improved Electroslag Cladding Method

Cao

Dong

Deng

et al. 2018

Metals

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In the present study, a new electroslag cladding method by using of the advanced current supplying mold technology was used for manufacturing the high speed steel (HSS)/ductile cast iron (DCI) composite roll. The graphite morphology, matrix microstructure, elements distribution, carbides morphology, and carbides composition have been investigated by means of optical microscope (OM), scanning electron microscope (SEM), and energy dispersive spectroscopy (EDS). With increasing distance from the HSS side, a transition of graphite morphology from naught to existence and from small and dispersed to large and nonuniform was obtained at the interface. It was closely related to the fact that graphite in DCI participated in the phase change and the roll core surface and its nearby positions was heated to a high temperature by the liquid slag during the whole electroslag cladding process. Due to the combined effects of melting and elements diffusion, a significant migration of the alloying elements have occurred through the line scan analysis. Based on this, different types of carbides with the morphology and composition were found at the bonding interface. In addition, no obvious slag inclusions, porosity, shrinkage and other defects at the bonding interface were found. Results of the tensile test also illustrated that the bonding interface had a good quality and it could fully meet the requirements of the roll.

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“…For this reason, the requirements of these manufacturers include a volume fraction of pearlite lower than 5%, in addition to a spheroidal morphology in the primary graphite (Lacaze et al, 2016). Recent studies have shown that factors such as graphite morphology and the number of graphite nodules per unit area have a significant effect on the in-service behaviour of the material, especially its fatigue strength (Shiraki et al, 2016).…”

Section: Introductionmentioning

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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Effects of Number of Graphite Nodules on Fatigue Limit and Fracture Origins in Heavy Section Spheroidal Graphite Cast Iron

Cited by 11 publications

References 4 publications

Novel method for the fatigue strength assessment of heavy sections made by ductile cast iron in presence of solidification defects

Novel method for the fatigue strength assessment of heavy sections made by ductile cast iron in presence of solidification defects

Research on the Bonding Interface of High Speed Steel/Ductile Cast Iron Composite Roll Manufactured by an Improved Electroslag Cladding Method

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

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