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Increasing Productivity in Nr. 1
Horizontal Continuous Casting
The Process
Horizontal continuous casting is a
process in which solidifying metal is
extracted horizontally through a cooling
Productivity is a crucial issue in
unit. Figure 1 illustrates schematically
continuous casting, as well as in this process.
all other industrial processes. The
key to an increase in productivity
remains often in the control of all
operational parameters. However, Figure 1: Horizontal
the relative influence of each continuous casting. (1)
experimental parameter has foundry ladle, (2) crucible,
(3) graphite sleeve, (4)
traditionally to be determined casting, (5) cooling unit &
using long and expensive trial (6) withdrawal rolls. (Ref.:
runs. Simulation is another, more Institute of Technology of
Metals, Belarus)
convenient and accurate method
to understand and analyse the
importance of each casting
Generally a saw is set up after the
parameter. The influence of withdrawal rolls, in order to cut the
operational data such as casting casting at constant lengths. This process The Case
speed, cooling condition or inlet is used mainly for copper alloys and cast A copper alloy rod producer has
iron. Such a casting unit can typically undertaken a complete re-evaluation of
temperature can be analysed
produce 300 to 600 Kg/h of bronze, or its continuous casting process. The
rapidly, independently and cost
700 to 1'400 Kg/h of cast iron. objective was to increase productivity by
efficiently. a factor 3 but keeping the same
The castings are semi-finished products, metallurgical properties. The engineers
In this case study, simulation has which are further processed in extrusion, had therefore to find a way to increase
drawing, rolling or remelting operations. casting speed without affecting the
been used to increase the
The quality of the castings depends shape of the solidification front.
productivity of an horizontal mainly on the processing conditions. In
continuous casting machine. The this respect, the position and the shape
key factors influencing the heat of the solidification front (light blue in
the bottom image of figure 2) plays a
extraction in the cooling system
significant role. Therefore, it is of prime
have been determined. The process importance to closely control the cooling
modifications proposed have led to conditions.
a net productivity increase of
25%.
Figure 2 : Temperature field (top) and
solidification front (bottom) in the horizontal
continuous caster (simulation run with
calcosoft®-2D)
The Analysis optimal cooling condition would be to The temperature jumps correspond to
In terms of casting parameters, remove all the mould elements and to the interfaces. The main resistance to
increasing productivity, keeping the same cast directly into water. This would not be heat flow is therefore located at the
material properties, means casting faster possible in practice, as liquid metal boundaries between the elements of the
and extracting more heat. Foundry would flow directly into the water, mould. The highest temperature drop
experience can feed many casting without solidifying into a consistent appears to be between the casting and
improvements, but it is not possible to casting. This case has been run and the graphite sleeve. Any improvement in
know accurately where and how the showed a maximal increase in casting the quality of the contact between these
metal solidifies in the mould. Therefore, speed of 70%. Far from the requested two elements would lead to a dramatic
it was rather difficult to run proper productivity increase and still an increase of the heat extraction capacity.
process optimisation in the foundry. unrealistic solution, this simulation was
the starting point for the process The cooling conditions could be
In order to actually see what is happening optimisation, setting the maximum optimised by modifying the geometry of
inside the casting machine, simulation theoretical velocity. From there on, the the various cooling elements. This in turn
was used. Figure 2 shows 2D crosscuts of mould elements have been added step opened the possibility to cast faster but
one of the casting setups. The upper by step, rebuilding hereby the casting. still keeping the same solidification front.
image represents the temperature field The casting speed increase was around
whereas the lower image represents the The thermal analysis of the complete 25% of the initial casting speed. Once
liquid zone in white, the mushy zone in setup showed where the heat extraction the changes on the machine had been
light blue and the solid in blue. could be increased. Figure 3 shows the operated, it represented an equivalent
temperature profile from the outside of increase in productivity.
Simulation also allows foundrymen to the mould to the inside of the billet in the
run castings in unrealistic situations. An solidification region.
Conclusion
The importance of each parameter, such
as the thickness of the graphite shell or
the contact between the graphite and the
cooling jacket have been analysed
separately. Thermal modelling of the
process showed that the interfaces
Figure 3:
Temperature profile between the mould components
from the outside of represent the main resistance to heat
the mould to the extraction. Working on the different
center of the casting, elements constituting the mould, the
through the copper engineers could develop a new casting
cooler and the design, allowing a net production
graphite sleeve increase of 25%.
(simulation run with
calcosoft®-2D)
Calcom SA
calcosoft® is a registered trademark for a Parc Scientifique EPFL, CH-1015 Lausanne, Switzerland
phone: +41 21 693 2918 / fax: +41 21 693 4740
software dedicated to continuous casting.
mail@calcom.ch / www.calcom.ch
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