Chunky Graphite - Recognition, Quantification, and Impact on Properties of Spheroidal Graphite Cast Iron
- Since there is a continuously growing demand for complex, frequently heavy-sectioned spheroidal graphite cast iron (SGI) castings it is worth paying attention to the chunky graphite (CHG) degeneration which may occur under certain technological circumstances. Although a reference line for preventive actions in terms of general metallurgical and process measures could be drawn to avoid CHG in heavy-sectioned ferritic SGI castings, a broad majority of experts claim the avoidance of CHG in heavy sections cannot yet be rated a hundred percent process safe. A major reason may be seen in the fact that a universal, generally accepted explanation of CHG formation and growth has not yet been established, although several theories have been proposed. Nevertheless, metallurgical aspects are not in the focus of this paper. This paper is about the current state of methods to detect CHG in SGI on the laboratory and component scales. Capabilities and limits of different metallographic, fractographicSince there is a continuously growing demand for complex, frequently heavy-sectioned spheroidal graphite cast iron (SGI) castings it is worth paying attention to the chunky graphite (CHG) degeneration which may occur under certain technological circumstances. Although a reference line for preventive actions in terms of general metallurgical and process measures could be drawn to avoid CHG in heavy-sectioned ferritic SGI castings, a broad majority of experts claim the avoidance of CHG in heavy sections cannot yet be rated a hundred percent process safe. A major reason may be seen in the fact that a universal, generally accepted explanation of CHG formation and growth has not yet been established, although several theories have been proposed. Nevertheless, metallurgical aspects are not in the focus of this paper. This paper is about the current state of methods to detect CHG in SGI on the laboratory and component scales. Capabilities and limits of different metallographic, fractographic and non-destructive computer tomographic methods to recognize and quantify CHG are discussed. With respect to the characteristic fili-gree three-dimensional string-like, multi-branched CHG structure, which is non-isometric and non-dispersed, serious implications on the possibility to quantitatively characterize the amount of CHG must be considered. In contrary to the metallurgical aspects, the knowledge about the impact of CHG on the materials and com-ponents properties is still surprisingly limited. Therefore, special emphasis of this paper is on the impact of CHG degeneration on the properties of ferritic SGI. Experimental results are reviewed to illustrate the effect of CHG on mechanical strength and ductility properties as well as fracture mechanics properties in terms of crack resistance and fracture toughness. The present situation is characterized by discussions and uncertainty about the acceptance or rejection of SGI components containing CHG. Addressing this, conclusions from the materials engineering point of view are drawn for quality control, a safe operational strategy in the foundry and component safety.…
Autor*innen: | Wolfram BaerORCiD |
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Persönliche Herausgeber*innen: | C. Bleicher, H. Kaufmann, C. Pittel |
Dokumenttyp: | Beitrag zu einem Tagungsband |
Veröffentlichungsform: | Verlagsliteratur |
Sprache: | Englisch |
Titel des übergeordneten Werkes (Englisch): | InCeight Casing 2023 |
Jahr der Erstveröffentlichung: | 2023 |
Organisationseinheit der BAM: | 9 Komponentensicherheit |
9 Komponentensicherheit / 9.6 Additive Fertigung metallischer Komponenten | |
Herausgeber (Institution): | Fraunhofer LBF Darmstadt |
Verlag: | Fraunhofer Verlag |
Erste Seite: | 1 |
Letzte Seite: | 11 |
DDC-Klassifikation: | Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurwissenschaften und zugeordnete Tätigkeiten |
Freie Schlagwörter: | Chunky graphite; Ferritic spheroidal graphite cast iron; Fracture toughness; Quantification; Recognition; Structure; Tensile properties |
Themenfelder/Aktivitätsfelder der BAM: | Material |
Material / Degradation von Werkstoffen | |
Veranstaltung: | InCeight Casting Conference 2023 |
Veranstaltungsort: | Darmstadt, Germany |
Beginndatum der Veranstaltung: | 06.03.2023 |
Enddatum der Veranstaltung: | 08.03.2023 |
ISBN: | 978-3-8396-1892-9 |
Zugehöriger Identifikator: | https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/57121 |
Verfügbarkeit des Dokuments: | Datei im Netzwerk der BAM verfügbar ("Closed Access") |
Datum der Freischaltung: | 09.03.2023 |
Referierte Publikation: | Nein |