Measuring Heat Transfer during Twin Roll Casting of Metals
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Date
2011-01-17T20:31:57Z
Authors
Mehraram, Pedram
Journal Title
Journal ISSN
Volume Title
Publisher
University of Waterloo
Abstract
Accurate knowledge of the heat transfer coefficient during casting (between a molten
and/or semi-solid material and the mold) is critical to be able to develop representative
mathematical models for casting process such as Twin Roll Casting (TRC). In this project, an
experimental apparatus was developed to enable to measurement of the interfacial heat transfer
coefficient (HTC) at the interface between a liquid metal as it solidifies against a chill surface.
The experimental apparatus consists of a cylinder and piston surrounded by a heater to
melt the metal samples. Pressure can be applied at the top of the piston so that the pressure of the
liquid metal at the interface can be varied. The apparatus was instrumented with a number of
sensors so that the temperature in both the molten metal and chill surface could be monitored as
well as a force sensor so that the interfacial pressure and how it varies during solidification is
known. Using the measured temperature time history, the interfacial heat transfer was calculated
by using an inverse heat conduction method in conjunction with the known thermo-physical
properties of the chill and solidifying metal. The apparatus was tested successfully by using Sn-
7.5%Sb-3.5%Cu alloy as the casting metal solidifying against H13 tool steel chill block. In
addition, the effect of different values of chill roughness and test metal superheat were
investigated on the heat transfer coefficient.