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Eisengusswerkstoffe
Dokumenten-Nummer: 57858
Tagungsbeitrag
Sjögren, Torsten; Svensson, Henrik
Publikationssprache: Englisch
Study of the Eutectoid Transformation in Grey Cast Irons and its Effect on Mechanical Properties
Sudie über die eutektoide Umwandlung bei Gusseisen mit Lamellengraphit und ihr Einfluss auf die mechanischen
Eigenschaften
In this experimental study, six pearlitic grey cast irons with different Cu and Cr content, different section thicknesses
and different eutectoid cooling rates have been examined. The eutectoid cooling rate was approximated by casting
simulation analysis. The purpose of the experiments was to study the effect of the matrix structure on the overall
mechanical properties. An emphasis is put on the pearlite interlamellar spacing because this controls the resulting
mechanical properties to a large extent. By keeping the graphite structure constant, the effect of the matrix structure
was able to be studied. This was achieved by shake-out at temperatures above the eutectoid transformation range
followed by subsequent cooling in air, mould or in a furnace. The pearlite interlamellar spacing ranged from 90 to 330
nm for the matrices studied. Comparing the strength of the fine structured and coarse structured materials, the tensile
and yield strength was reduced by almost 50%. Regarding the elastic deformation, a weak increase in the tangent
modulus with increasing alloying content was observed. It was also observed that lower cooling rate decreased the
tangent modulus. The tangent modulus ranged between 70 and 110 GPa. Analysing the plastic deformation of the
materials, in terms of strain hardening exponent, n, and strength coefficient, K, a strong dependence on the pearlite
coarseness was observed. It was concluded that the effect of graphite particle length on tensile strength was negligible
and the major improvement on the strength was due to refinement of the pearlite.
SP Technical Research Institute of Sweden, Boras, SE; Swerea SWECAST, Jönköping, SE
Erscheinungsjahr 2010
S. S.157-162
Seiten/Bilder/Tabellen/Quellen: 6S
Eisengusswerkstoffe
Dokumenten-Nummer: 57851
Tagungsbeitrag
Soliman, Mohamed; Palkowski, Heinz; Nofal, Adel
Publikationssprache: Englisch
Thermo-Mechanically Processed Multi-Phase Ductile Iron: Microstructure Development
Thermomechanisch behandeltes Multi-Phasen-Gusseisen mit Kugelgraphit: Mikrogefüge-Entwicklung
Using thermo-mechanical simulator equipped with dilatometry system, two ductile iron alloys with different Mn-content
are processed by combining both, well defined deformation process and subsequent controlled cooling in a single
processing chain to control the final microstructure. Accordingly, ductile irons with four different structrues are
produced namely, martensite, ausferrite, martensite+ferrite and ausferrite+ferrite. Depending on the dilatometric
measurments, the ferrite formation temperature-range has been defined for both alloys. Preferential transformation of
austenite to ferrite at graphite nodules during cooling is observed. It is also observed that the formation of ferrite during
cooling results in both decreased martensite start of the undecomposed austenite and accelerated kinetics of ausferrite
formation.
Institut für Metallurgie, TU Clausthal, Clausthal-Zellerfeld, DE; Central Metallurgical R&D Institute (CMRDI), Helwan,
Cairo, EG
Erscheinungsjahr 2010
S. S.199-204
Seiten/Bilder/Tabellen/Quellen: 6S
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