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This two part casting presents a unique challenge in coupling fluid dynamics of
a filling process with remelting of a pre-cast cylinder of a double-poured dual
alloy casting.
Fig. 1: Flow patterns during casting.
Simulation of a Dual Alloy Casting
The molten bulk material is poured into the the precast
cylinder and the upper and lower molds, filling ends at
120s. Due to the pouring stream impact during filling, a
well-mixed zone exists to a depth approx 1 m below the
molten metal surface and is characterized by velocities on
the order of 0.1 to 1 m/s as shown in Fig. 1. Below the
well-mixed zone the flow is quiescent with relatively low
velocities less than 50 mm/s. Further analysis showing the
evolution of melting (shell thickness), liquid velocity, temperature,
and maximum effective thermal conductivity at
three points are shown in Fig. 2. The correlation of these
phenomena confirm the hypothesis that melting of the
cylinder occurs only during contact with the the turbulent
well-mixed zone of the bulk material.
Autumn Fjeld
Lehrstuhl für Modellierung und Simulation
metallurgischer Prozesse
an der MUL seit: 2006
Email: autumn.fjeld@unileoben.ac.at
www.smmp.at.hm
Zur Person:
Post Doctoral Research,
seit 2006: am Lehrstuhl für Modellierung und Simulation
metallurgischer Prozesse
The objective of this module is the analysis of filling induced
flow phenomena and prediction of melting in a two-part casting.
The bulk material (cast iron) is poured from above into a moldcylinder
assembly; the cylinder is a large precast tube of highly
alloyed steel assembled between upper and lower molds. The
durability of these castings is dependent upon optimum cylinder
re-melting: sufficient melting must occur for good bulk-cylinder
bonding, however an excess of melting results in contamination
of the bulk material from the highly alloyed cylinder. The interaction
of the turbulent bulk liquid and the melting of the cylinder
material has not been well understood by the industry partner,
providing an opportunity for the development of a numerical
model to analyze flow and melting phenomena.
Fig. 2: Evolution of cylinder melting during filling at three positions.
Forschungsschwerpunkte:
Casting Processes, Fluid Dynamics, Solidification and
Melting