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Version 020530
Adaptive Thermal Analysis System
ATAS White
Metallurgical Process Control for
Gray and Ductile Iron
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ATAS - Your Professional Tool for
Metallurgical Process Control
Chemical analysis (spectrometer) estimates the
percentage of each element in the melt. However, it
gives NO information about the nucleation status or
how graphite will precipitate during solidification.
That is why two melts with identical chemistry can
behave differently when poured!
Conclusion: Chemical analysis is Insufficient for
efficient process control!
Thermal analysis on the other hand shows what
really happens thermodynamically.
ATAS White is a very easy to use basic thermal
analysis system for tellurium-coated Quik-Cups.
ATAS White can be upgraded to ATAS Verifier and
other modules in the ATAS suite of tools.
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ATAS White and Active CEL
ATAS records values of
thermal parameters which,
more accurately than
chemistry, relate to what will
happen when the iron is
poured in a mold. The first
arrest temperature is
normally referred to as the
liquidus temperature. This
temperature is closely related
to the active carbon
equivalent. It is an integration
of the effect of C, Si, P, Al, O
and other elements.
The CEL estimated with
ATAS can therefore differ
from CEL calculated from the
chemical analysis. The ATAS
value will more accurately
represent how the iron will
behave.
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The White Eutectic Temperature
Carbon is precipitated as
cementite since the Quik-Cups
contain tellurium.
The white eutectic temperature
is a function of several
elements but mainly Si, P and
Cr.
The accuracy for silicon
determination is limited to
about +/- 0.12 %.
However, the white eutectic
temperature is an integration of
all active elements. The iron
will behave as usual with
respect to cementite if the
temperatures are within normal
limits. Therefore ATAS White
also uses temperatures as
control limits.
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The Active Carbon Equivalent
ATAS White measures the active
carbon equivalent, which will identify
the iron more accurately than the
CEL calculated using chemical
analysis of C, Si and P.
In this example chemistry showed
4.12%. However, the foundry
experienced a higher tendency
toward sunks and macro shrinkage.
ATAS verified this, as the active CEL
was only 4.03. The reason can for
example be increased amount of
dissolved oxygen, which reduces
carbon activity. ATAS therefore
shows reality!
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Selecting language, password, etc.
ATAS allows the user to
change password,
channels and other
parameters.
These data need to be
defined before taking
the system into
operation.
Each channel
represents one test
stand for Quik-Cups.
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Channel settings
ATAS can use up to 4
channels. For each
channel, various
parameters can be set
to values customised for
the application.
Each channel can be
calibrated.
Corrections can also be
entered for the QuikCups if certified cups
are used
(recommended).
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Alloy Database - Alarm limits
It is necessary to
define at least one
alloy when taking
ATAS into operation.
Any number of alloys
can be entered.
Both base iron and
final iron can of
course be analysed.
The targets in C, Si,
P and Cr are entered
for each alloy. ATAS
then suggests limits
to be used when
evaluating a sample.
The user can then
enter max and min
limits for the alloy.
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Coefficients for CEL, C and Si
ATAS White measures
the liquidus and the
white eutectic
temperatures. These
temperatures are used
to estimate the active
carbon equivalent
(CEL) as well as
carbon and silicon.
The coefficients for the
calculations can be
modified for each alloy
when needed. The
default values are valid
for most hypoeutectic
alloys and for
hypereutectic alloys up
to CEL=4.6. Other
coefficients must be
used for alloys with
CEL>4.6
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ATAS Complete Hardware
ATAS White, as well as the other ATAS Software modules,
requires specialised hardware to work properly. The
complete hardware consists of the following items:
1. PC Min. 1 GHz, 256 MB RAM
2. 15” LCD colour screen
3. Air-tight steel cabinet
4. High precision A/D converter
5. UPS - Power control
6. Test stand with cable
If there is a dust-free room in the foundry where a normal
computer can be used then only items 4,5 and 6 are
needed.
Up to 4 test stands can be connected to the system.
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ATAS A/D Converter
If the foundry has a control
room where a normal PC can
be installed then it is enough to
use the ATAS A/D converter.
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ATAS White - Opening Screen
ATAS White can be
connected to 4 sampling
sites. Each sampling site
can be poured
independently.
The lower part in the
screen indicates in this
case that a Quik-Cup
should be placed on the
test stand on channel 5
and 7.
ATAS feels when a QuikCup is placed on the
stand and indicates it
with a green frame. Then
the iron can be poured
into the cup at any time.
The alloy to be analysed
can be selected for each
sample station.
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Sampling with ATAS White
Measuring.
Measurement
CEL predicted
within 60 seconds
ready. CEL is wrong
When a Quik-Cup is filled with metal,
temperature and time are automatically
recorded and stored using a logger
function. The cooling curve is displayed
in the quadrant of the screen that
corresponds to the selected channel. The
active carbon equivalent is automatically
estimated, normally within less than 60
seconds. When the curve is ready it is
stored and the values for C and Si are
also displayed. If a sample is outside the
limits a ?-mark is shown. The value that
is outside its max or min values is
displayed with a red background. In such
cases a click on the lower left corner,
which shows the curve name, for a more
detailed view of the sample with
explanation. When an analysis is
completed the system is automatically
reset when a new Quik-Cup is put on the
stand.
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ATAS White - The Result Screen
This screen is used to
give a more detailed
view of the sample.
An alloy profile diagram
is displayed in the lower
part of the screen. The
actual values are
compared with
acceptable limits
determined for each
alloy.
The active CEL value is
ready within 60
seconds. When using
electric melting it means
less downtime while
waiting for analysis. This
saves energy and
increases output!
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ATAS White - Explanation screen
Each sample can be
evaluated using the
“Explain” screen. The
liquidus and eutectic
temperatures are
displayed in a decision
tree with the values in
the alloy database as
threshold limits.
It is important to
recognise that the
recorded temperatures
are a function of the
integrated effect of all
elements and
compounds in the melt.
That is why it is
important to use limits
for the temperatures.
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Statistical Process Control Chart
All results are stored
automatically.
An SPC chart, which
allows all the
parameters to be
inspected, is available.
The “scrollable”
window shows 10
samples at a time.
The limits for the
selected alloy are
shown as red lines.
The average value
and the standard
deviation are also
displayed.
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Why ATAS White?
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Method for quality assurance
Accurate values for active CEL, C, Si
Increased productivity in electric melting!
Carbon Equivalents up to 4.6 %
Alarm functions
Explains results, suggests actions
SPC -charts and documentation
Automatic - very easy to use
Supported by specialists in TA and metallurgy
Easy to upgrade to ATAS Verifier
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ATAS - The Complete System for
Metallurgical Process Control
ATAS White is a modern version of traditional thermal analysis.
ATAS Verifier is a more advanced system, which uses grey solidification. It is suitable for foundries
that want a more detailed metallurgical process control system.
ATAS is supported by experts in metallurgy
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© NovaCast AB