Aachen, September 6th 2012
Benefits of thermodynamic simulations
in an industrial setting
F. Hagemann, B. Maas, B. Springub
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Benefits of thermodynamic simulations in an industrial setting
Agenda
Introduction
Salzgitter AG
Salzgitter Mannesmann Forschung GmbH (SZMF)
Thermo-Calc use modes
Examples
Liquidus temperature calculation for casting temperature control
Continuous casting:
Solidification interval modification
Identification of peritectic transformation
Hot rolling: Post mortem analysis of martensite formation
Summary and conclusion
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Benefits of thermodynamic simulations in an industrial setting
Agenda
Introduction
Salzgitter AG
Salzgitter Mannesmann Forschung GmbH (SZMF)
Thermo-Calc use modes
Examples
Liquidus temperature calculation for casting temperature control
Continuous casting:
Solidification interval modification
Identification of peritectic transformation
Hot rolling: Post mortem analysis of martensite formation
Summary and Conclusion
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Benefits of thermodynamic simulations in an industrial setting
• Crude steel production: 6.9 million tons; trading volume: 6.8 million tons
• Among the top 3 producers of beverage filling und packaging machinery
Salzgitter AG: Global Presence
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Benefits of thermodynamic simulations in an industrial setting
Salzgitter AG: Diversified product portfolio
Line pipes
Precision tubes
Stainless tubes
Stockholding trading
International trading
Strip products
Heavy plates
Sections
Engineering services
Logistics
Injection molding machinery Beverage filling plants
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Steel
and
Technology
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Benefits of thermodynamic simulations in an industrial setting
Salzgitter AG
Salzgitter AG (Holding)
Salzgitter Mannesmann GmbH – Intermediate Holding Company
SteelSalzgitter Stahl GmbH
Trading ServicesTubesMannesmannröhren-
Werke GmbH
TechnologyKlöckner-Werke AG
Salzgitter Flachstahl Europipe (50%)Salzgitter Mannesmann
Handel GruppeKHS-Gruppe DEUMU
Ilsenburger GrobblechSalzgitter Mannesmann
LinepipeUniversal
Klöckner DESMA
Elastomertechnik
Salzgitter Service
und Technik
Peiner TrägerSalzgitter Mannesmann
PrecisionHövelmann & Lueg
Klöckner DESMA
Schuhmaschinen
Verkehrsbetriebe
Peine-Salzgitter
HSP Hoesch Spundwand
und Profil
Salzgitter Mannesmann
Stainless Tubes
Klöckner Hänsel
ProcessingTelcat
Salzgitter BauelementeSalzgitter Mannesmann
GroßrohrGESIS
Salzgitter EuroplatinenHüttenwerke Krupp
Mannesmann (30%)Hansaport (51%)
Salzgitter Mannesmann
Grobblech
Salzgitter Mannesmann
Forschung
Salzgitter Automotive
Engineering
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Benefits of thermodynamic simulations in an industrial setting
Crude steel production 2008: 5.3 mt Segment Sales: € 4.3 billion
Shipments 2008: 5.4 mt External Sales: € 3.0 billion
Salzgitter AG: Steel Division – Overview
Steel Division
Heavy plate Sections Processing Strip steel
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• largest subsidiary
• integrated iron & steel works
• hot-rolled strips and sheets• cold-rolled sheets
• surface-finished products
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Benefits of thermodynamic simulations in an industrial setting
Materials and process development
Metallographic and metallurgicmaterials characterization
Process analysis and numericalsimulation
Materials development
DSC/BCTMaterials and processes
NDT
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Benefits of thermodynamic simulations in an industrial setting
Agenda
Introduction
Salzgitter AG
Salzgitter Mannesmann Forschung GmbH (SZMF)
Thermo-Calc use modes
Examples
Liquidus temperature calculation for casting temperature control
Continuous casting:
Solidification interval modification
Identification of peritectic transformation
Hot rolling: Post mortem analysis of martensite formation
Summary and Conclusion
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Benefits of thermodynamic simulations in an industrial setting
How do we use Thermo-Calc?
TCS
TCW
...and our own ‚automatisation‘ in the form of Perl scripts:
• Set of chemical compositions
(csv file: C, Si, Mn, ....)
• Type of calculation
(Tliq, equilib. phase fractions, ...)
Input:
1. Parse input
2. Write tcm scripts
• based on a set of templates
• one script for each chem. comp.
• templates for different type of calc.
3. Run tcs with scripts
4. Parse output, check for errors,
extract results
Perl-Scripts:
csv file:
• Chemical composition
• Calculation result
(Tliq, equilib. phase fractions, ...)
• Error condition
Output:
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Benefits of thermodynamic simulations in an industrial setting
Agenda
Introduction
Salzgitter AG
Salzgitter Mannesmann Forschung GmbH (SZMF)
Thermo-Calc use modes
Examples
Liquidus temperature calculation for casting temperature control
Continuous casting:
Solidification interval modification
Identification of peritectic transformation
Hot rolling: Post mortem analysis of martensite formation
Summary and Conclusion
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Benefits of thermodynamic simulations in an industrial setting
Steel production – A very brief overview
Reheating
Hot Rolling
Cold RollingSkin Passing
Surface Finishing
Steel works
Pig Iron
Coke
Iron Ore
Charging
Hot Air
Blast Furnace
Roughing
Annealing
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Benefits of thermodynamic simulations in an industrial setting
Calculation of liquidus temperatures (1)
converter
arrival ladle treatm.
finish ladle treatm.
cont. casting
liquidus temperature
time
tem
pe
ratu
re
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Benefits of thermodynamic simulations in an industrial setting
Calculation of liquidus temperatures (2)
Approach by Schürmann (Schürmann et al., steel research 68, 1997):
Calculation of carbon equivalence factors
xi from liquidus lines of binary Fe-Xi systems
Model ∆xi as a second order polynomial
Fit ai,bi to Fe-Xi binary systems
Calculate total carbon equivalence factor:
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Benefits of thermodynamic simulations in an industrial setting
Calculation of liquidus temperatures (2)
Approach by Schürmann (Schürmann et al., steel research 68, 1997):
Calculation of carbon equivalence factors
xi from liquidus lines of binary Fe-Xi systems
Use the Fe-C system to calculate Tliq
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Benefits of thermodynamic simulations in an industrial setting
Calculation of liquidus temperatures (3)
Original works by Schürmann et al.
Coefficients a and bLiquidus lines
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Benefits of thermodynamic simulations in an industrial setting
Calculation of liquidus temperatures (4)
Our modifications:
Use Thermo-Calc to calculate liquidus lines
Fit third order (instead of second order) polynomials to those
Include more elements (e.g. B, Ti)
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Benefits of thermodynamic simulations in an industrial setting
Calculation of liquidus temperatures (5)
Cr-Stahl C Mn Si Cr Ni Mo V TLiquid, Exp TLiquid, TC TLiquid, Modell
wt. % 0,310 0,935 0,271 3,640 0,654 1,110 0,312 1491,8°C 1493,6°C 1493,3°C
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1400 1420 1440 1460 1480 1500 1520 1540
Temperatur [°C]
Ph
ase
na
nte
il [-]
Liquid
Ferrit
Austenit
TLiquidus=1493.6°C
TSolidus=1440.1°C
TSolidus =1478,1°CTLiquidus =1491,8°C
C Mn Si Cr Ni TLiquid, Exp TLiquid, Schürmann TLiquid, Modell
0,25% 1,43% 0,28% 0,25% 0,19% 1505°C 1504,7°C 1505,4°C
Literature example (Schürmann)
High Cr-steel
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Benefits of thermodynamic simulations in an industrial setting
Calculation of liquidus temperatures (6)
Comparison: Old empirical model vs. new Schürmann based
Results:
Process stability increased through better Tliq prediction
(avoid ladle freezing)
Unified description for all produced steel grades (instead of
separate models, e.g. specific to carbon steels)
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Benefits of thermodynamic simulations in an industrial setting
Steel production – A very brief overview
Reheating
Hot Rolling
Cold RollingSkin Passing
Surface finishing
Steel works
Pig Iron
Coke
Iron Ore
Charging
Hot Air
Blast Furnace
Roughing
Annealing
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Benefits of thermodynamic simulations in an industrial setting
Continuous casting
Various questions: – often as a result of surface defects (e.g. sliver defects)– often routine tasks
Examples:
Adjustment of the solidifaction interval by changing thesteel composition
Check for peritectic solidification
Identification of possible precipates during strand coolingthat may lead to embrittlement
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Benefits of thermodynamic simulations in an industrial setting
Steel production – A very brief overview
Reheating
Hot Rolling
Cold RollingSkin Passing
Surface finishing
Steel works
Pig Iron
Coke
Iron Ore
Charging
Hot Air
Blast Furnace
Roughing
Annealing
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Benefits of thermodynamic simulations in an industrial setting
4 reheating furnaces
water descaling
sizing press
roughing train
cropping shear
3 down coilersfinishing train7 stands
slab thickness = 250mmsheet thickness = 1.5…25mmsheet width = 900…2000mmcapacity = approx. 3.5 Mt/yearProduct range:Complex phase steels, ULC, HSLA, carbon steels up to C75, steels for line pipes, tempering steels
Hot strip mill
run-out table (ROT)
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Benefits of thermodynamic simulations in an industrial setting
Post mortem analysis of martensite formation (1)
wt. %
C 0.05
Si 0.3
Mn 1.8
Cr + Mo 0.4
Ti + Nb 0.11
X80, 18.9 mm
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Benefits of thermodynamic simulations in an industrial setting
Low CT
Post mortem analysis of martensite formation (2)
wt. %
C 0.05
Si 0.3
Mn 1.8
Cr + Mo 0.4
Ti + Nb 0.11
X80, 18.9 mm
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Benefits of thermodynamic simulations in an industrial setting
Post mortem analysis of martensite formation (3)
wt. %
C 0.05
Si 0.3
Mn 1.8
Cr + Mo 0.4
Ti + Nb 0.11
X80, 18.9 mm
High CT
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Benefits of thermodynamic simulations in an industrial setting
Post mortem analysis of martensite formation (4)
wt. %
C 0.05
Si 0.3
Mn 1.8
Cr + Mo 0.4
Ti + Nb 0.11
High CT: about 20% martensiteLow CT: no martensite
X80, 18.9 mm
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Benefits of thermodynamic simulations in an industrial setting
X80, 18.9 mm45% of ferrite
Massive carbon
enrichment in austenite
⇒ Stabilization of
austenite
⇒ Martensite formationduring coil cooling
Post mortem analysis of martensite formation (5)
Small amount of ferrite
No carbon enrichment
in austenite
⇒ Formation of bainite
wt. %
C 0.05
Si 0.3
Mn 1.8
Cr + Mo 0.4
Ti + Nb 0.11
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Benefits of thermodynamic simulations in an industrial setting
Summary and conclusion
Thermo-Calc and Dictra - Useful tools for us:
Liquidus temperatures
Solidification intervals
Peritectic transformation
Phase transformation and carbon enrichment on the ROT
...
Major benefits in supporting process and material development
by providing quick estimates without materials’ synthesis or a
trial production run.
Experimental validation and verification of results
remains a top priority.
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Benefits of thermodynamic simulations in an industrial setting
Thank you for your kind attention.
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