Analysis of the thixoability of ASTM A536 ductile iron

• Autorzy: Robert M. H. , Cristofolini R.
• Języki publikacji: EN

Abstrakty

EN

Purpose: Thixoability of the ASTM A536 nodular cast iron is analyzed, it meaning its ability to hold a thixotropic semi-solid state and to be formed as such. Thixoability can be characterized by the solidification range, fraction of primary phase and sensitiveness of liquid fraction with temperature (df1/dT) within the solidification range. It is also investigated the effect of thixocasting in the microstructure of the considered alloy. Design/methodology/approach: Differential thermal analysis, differential scanning calorimetry and thermodynamic calculation package THERMOCALC were used to predict transformations temperatures involving liquid formation and df1/dT within the solidification range. Microstructures of thixotropic slurries produced by partial melting were observed. Findings: Thixoforming of ASTM A536 nodular iron can be considered in a narrow window of about 28° C, were some dissolution of graphite nodules can still be afforded; this window meaning the range of temperatures of co-existence of austenite + graphite + liquid were the eutectic transformation is taking place. At higher temperatures the dissolution of graphite nodules in liquid can be significant. Research limitations/implications: Thixoability prediction models rely on sensitive experiments as thermoanalysis, with results strongly dependent on experimental conditions; and on thermodynamic data, sometimes not available or reliable for a specific alloy composition. Practical implications: The prediction of the thixoability of a certain alloy can make it more effective its thixoprocessing, allows better control of processing parameters and quality of final product; can also subsidize modifications in the alloy to make it more suitable to semi-solid processing. Originality/value: The study of the thixoability of a nodular hypereutectic cast iron is an original subject, not available in the specialized literature, however absolutely necessary if thixoprocessing of this family of alloys is to be considered.

Słowa kluczowe

EN

casting; thixoability; thixoforming; semi-solid alloys

PL

odlew; zdolności tiksotropowe

• Wydawca: International OCSCO World Press
• Czasopismo: Journal of Achievements in Materials and Manufacturing Engineering
• Rocznik: 2008
• Tom: Vol. 28, nr 2
• Strony: 115--122
• Opis fizyczny: Bibliogr. 15 poz., wykr.

Twórcy

autor

Robert M. H.

autor

Cristofolini R.

• Faculty of Mechanical Engineering, State University of Campinas, Sao Paulo, Brazil,

Bibliografia

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