Transcript Ravi-Haldipur-Ramana..

ATAS Metallurgical
Process Control
2013-03-02
Metallurgical Process control systems
© NovaCast Foundry Solutions AB
Basic needs of a foundry
Improved
customer
confidence
Low
environmental
impact
Competitive
edge
High Yield
Low direct
costs
Process
stability
(Reliability)
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Improved
financial
results
The purpose of process control
World
Class
Automate
Simplify
Control
Chaos
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Do I have all data needed to control my process?
?
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•
Day 1
C = 3,4 %
Si = 2,1 % , 1380°C
Rejection rate = 2,0 %.
All measured data OK!
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•
Day 2
C = 3,4 %
Si = 2,1 % , 1380°C
Rejection rate = 12,0 %
All measured data OK!
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The purpose of process control
You get what you measure
If it´s not measured it cannot be improved
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Chemical & Thermal Analysis
The spectrometer shows the amount in
% of different elements in the melt.
The metallurgical key temperatures show the
total effect of elements, oxides, silicates,
dissolved oxygen, combined oxygen and other
gases in the melt.
It is the effect that is important to know for process control!
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Disadvantages of only using the spectrometer
You will not receive any
information about ….
•
•
•
•
•
created compounds
oxides, silicates, sulphides etc
chemical reactions
nucleation or precipitation of graphite
the dynamics of solidification
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The metallurgical “Fingerprint”
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Controlling the process with 6 Basic
parameters
Liquidus
Low eutectic
Recalescence
Graphite
factor 1
Solidus
Graphite
factor 2
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Liquidus - TL
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Adjusting CEL with Spectro
If C and Si are within limits then the iron is considered to be OK.
Example:
C = 3.30 - 3.45
Si = 2.0 - 2.2
P = 0.05 - 0.1
CEL = C + Si/4 + P/2. CEL min=3.83 CEL max=4.05
Variation +/- 0.11
Variation in TL = 1168 – 1193 = 25 C
R I S K FO R D E F EC T S
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Low eutectic - TElow
TElow = f ( Nucleation status, Disolved Oxygen & Oxides )
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Thermal parameters
TELow
TElow, The low eutectic temperature
(a high value is essential).
If TElow is too low then the nucleation is
too low. Risk for chill in corners and thin
sections. Risk for undercooled graphite
shapes.
TElow
TElow ≤ 1135°C
Primary Carbides
PRESENT
TElow > 1135°C
Primary Carbides
FREE
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14
Recalescence - R
R = f ( Nucleation rate + Eutectic growth )
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Graphite factor 1 – GRF1
GRF 1 = f ( under cooling, precipitation speed, amount of graphite)
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Thermal parameters
GRF1
GRF 1, Graphite Factor 1 (a medium
value is good).
If too low it is an indication that the carbon content
might be too low especially if R is low or normal. It
also indicates that the precipitation of graphite is
lower than normal, which might be due to bad
nucleation. A low GRF 1 indicates a risk for micro-
GRF1
shrinkages.
GRF1 ≤ 75
Porosity
75 < GRF1 < 120
Porosity FREE
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GRF1 > 120
Chunky
17
Graphite factor 2 - GRF2
GRF 2 = f ( Graphite shape & amount )
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Thermal parameters
GRF2
GRF2
GRF2 < 35
35 ≤ GRF2 ≤ 55
GRF2 > 55
DEGENERATED
GRAPHITE
MICROSHRINKAGE
FREE
MICROSRHINKAGE
PRESENT
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19
Solidus - TS
TS = f ( Segregation, Mg )
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Controlling shrinkages
T,°C
Dendrites
S1
Eutecticum
S2
S3
t,s
Outher sunks
Macro Shrinkage
Micro shrinkage / Porosity
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ATAS can detect problems long
before they end up in the casting…
Improve
Correct
Stop
Detect
…and introduce a system for
continuous improvement
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First sample – Base iron DB
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23.
Second sample – Base iron DB
Optimal
Base iron
achieved!
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24.
Third sample – Uninoculated Final iron DB
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25.
Fourth sample – Inoculated Final iron DB
Optimal
Final iron
with low Mgadditions!
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26.
Summary
ATAS provides important control of the
metallurgical process, helping foundries to
better understand the metallurgical
implications that are affecting the final
product quality
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27.
Summary
With ATAS the foundry can control and
adjust vital processing steps such as:
•Raw Material Selection
•Chemical Composition
•Preconditioning
•Magnesium Treatment
•Inoculation
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28.
ATAS Alloy Database
Contains specific parameters for different
stages in the process, from Base to Final iron
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Conclusion
Establish a cost effective Charge mix
Reduction of Inoculation
Reduction of Rejection Rates
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Conclusion
Improved Machinability
Consistent quality, mechanical properties and
microstructure
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Conclusion
Provides Evaluation
Provides Statistics
Provides Data Management
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Tailored solutions
Process control by ATAS can be tailored to become a part of the
everyday process at any foundry, prepared to be connected to
demanding networks and complex server systems
Man + Machine + Method
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•…measures the effect of all elements and
compounds
• …creates a system for continuous improvement
• …ensures stability of the metallurgical process
• …essential for Ductile Iron production
• …can be profitable within 6 months
• …is used by people
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ATAS Metallurgical
Process Control
2013-03-02