TITLE:
Effect of Deformation Parameters on Microstructural Evolution of GGG 40 Spheroidal Graphite Cast Iron Alloy
AUTHORS:
Marwan Faisal, Eman El-Shenawy, Mohamed A. Taha
KEYWORDS:
Ductile Iron, Thermo-Mechanical Behavior, Gleeble-3500, Physical Simulation, Graphite Morphology
JOURNAL NAME:
Materials Sciences and Applications,
Vol.10 No.6,
June
5,
2019
ABSTRACT: Studying the
thermo-mechanical behavior of ductile iron is necessary to develop the rolling
process for ductile iron sheet/strip production, thus, extending its
application by replacing steel in several fields such as machine casing,
constructional applications, etc. In order to predict the safe rolling
conditions for producing sheets and strips, the thermo-mechanical behavior of a
ductile iron alloy, with CE of 4.48, is studied by physical simulation of hot
rolling process using Gleeble-3500 simulator. The test was conducted on
specimens at a range of deformation temperatures from 800°C to 950°C while
three different strain rates; namely 0.05, 0.1 and 0.5 s-1 were
used. The results obtained, show minimum values of flow stresses at 850°C. By
increasing the deformation temperature up to 900°C, the flow stresses increased
to reach maximum values, beyond which the flow stress decreased again. A
remarkable dynamic recrystallization is observed at the deformation
temperatures of 850°C and 800°C with applied strain rates of 0.05 and 0.1 s-1.
Gleeble test results are correlated with microstructure observations on samples
quenched at their deformation temperatures, where the changes in structure and graphite
morphology are reported. The deformation process at high temperatures namely
950°C and 900°C result in changing the graphite shape from a spheroidal-like to
a saucer-like shape. However, by decreasing the deformation temperature to 850°C
as well as 800°C, graphite with lamellar shape is observed. As a conclusion,
ductile iron could be successfully deformed without cracking at the applied
conditions.