Maximum Casting Speed for Continuous Casting Steel Billetsccc.illinois.edu/s/2001_Presentations/cli1/Cli_presentation... · University of Illinois at Urbana-Champaign • Metals Processing

University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • Chunsheng Li • 1

Chunsheng Li

Department of Mechanical & Industrial EngineeringUniversity of Illinois at Urbana-Champaign

October 18, 2001

Chunsheng Li

Department of Mechanical & Industrial EngineeringUniversity of Illinois at Urbana-Champaign

October 18, 2001

Maximum Casting Speed for Continuous Casting Steel Billets

Maximum Casting Speed for Continuous Casting Steel Billets


ObjectiveObjective

Analyze bulging below the mold for unsupported billet bloom casting due to ferro-static pressure for different casting speeds.Determine critical casting speed to avoid cracks as a function of section size and mold length.

Analyze bulging below the mold for unsupported billet bloom casting due to ferro-static pressure for different casting speeds.Determine critical casting speed to avoid cracks as a function of section size and mold length.


Model DescriptionsModel Descriptions

Finite element thermal stress modelPhase fractions from non-equilibrium Fe-C phase diagram for plain carbon steelRecalescence and kinetics neglectedLinear phase fraction model between liquidus and solidus for ferritic and austenitic stainless steels2-D generalized plane strain

Finite element thermal stress modelPhase fractions from non-equilibrium Fe-C phase diagram for plain carbon steelRecalescence and kinetics neglectedLinear phase fraction model between liquidus and solidus for ferritic and austenitic stainless steels2-D generalized plane strain

flowthermalcreepplasticelastictotal εεεεε &&&&& +++= /


Heat Transfer Model ValidationHeat Transfer Model Validation

• Lines: Boley & Weiner’s analytical solution*• Symbols: CON2D computation results

* J. H. Weiner and B. A. Boley, J. Mech. Phys. Solids, 1963, Vol. 11, pp145-154

Distance from Slab Surface (mm)

Tem

per

atu

re(C

)

0 10 20 301000

1100

1200

1300

1400

1500

5 sec.5 sec.10 sec.10 sec.15 sec.15 sec.20 sec.20 sec.25 sec.25 sec.30 sec.30 sec.35 sec.35 sec.43 sec.43 sec.


Stress Model ValidationStress Model Validation

• Lines: Boley & Weiner’s analytical solution*• Symbols: CON2D computation results

* J. H. Weiner and B. A. Boley, J. Mech. Phys. Solids, 1963, Vol. 11, pp145-154

Distance from Slab Surface (mm)

YS

tres

s(M

Pa)

0 10 20 30-25

-20

-15

-10

-5

0

5

10

15

5 sec.5 sec.10 sec.10 sec.15 sec.15 sec.20 sec.20 sec.25 sec.25 sec.30 sec.30 sec.35 sec.35 sec.43 sec.43 sec.


Steel Properties AssumedSteel Properties Assumed

Mizukami elastic modulus dataTemperature dependent conductivity, enthalpy and thermal linear expansion.Kozlowski constitutional equations for austenite, and modified model for delta-ferrite: – Kozlowski Model for Austenite – Modified Power Law Model for δ-ferrite

Mizukami elastic modulus dataTemperature dependent conductivity, enthalpy and thermal linear expansion.Kozlowski constitutional equations for austenite, and modified model for delta-ferrite: – Kozlowski Model for Austenite – Modified Power Law Model for δ-ferrite


Constitutive Model Constitutive Model

0.1

1

10

1200 1250 1300 1350 1400 1450 1500 1550

dε/dt 2.8e-5 s-1

dε/dt 2.3e-2 s-1

ELEC FEFE-0.028CFE-0.044CFE-3.0SI

Temperature (Degree C)

Wray Data

Constitutive Model

γ δ+γ

δ+

δ

L

10% δ


Non-equilibrium phase diagram* of plain carbon steels** used in CON2DNon-equilibrium phase diagram* of plain carbon steels** used in CON2D

1300

1350

1400

1450

1500

1550

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

Carbon content (%)

Tem

pera

ture

(C)

LL+δ

δ L+δ+γ

δ+γ L+γ

γ

• *Young Mok WON et. al., Effect of Cooling Rate on ZST, LIT, ZDT of Carbon Steels Near Melting Point”, ISIJ International, Vol. 38, 1998, No. 10, pp. 1093 –1099

• **Other Steel Components: 1.52%Mn, 0.34%Si, 0.015%S, 0.012%P

• *Young Mok WON et. al., Effect of Cooling Rate on ZST, LIT, ZDT of Carbon Steels Near Melting Point”, ISIJ International, Vol. 38, 1998, No. 10, pp. 1093 –1099

• **Other Steel Components: 1.52%Mn, 0.34%Si, 0.015%S, 0.012%P

0.0 0.2 0.4 0.6 0.8 1.01300

1350

1400

1450

1500

1550

Liquid

δ+γ

δ+γ+L

δ+L

γ+L

γ

δ

fS=0.0

fS=0.75

fS=1.0

ZST(exp.)[2] ZDT(exp.)[2] Fe-C equilibrium diagram present FDM simple model

Tem

pera

ture

, o C

Carbon Content, wt%


ConductivityConductivity

Temperature (oC)

Co

ndu

ctiv

ity(W

/mK

)

800 1000 1200 1400 160028

29

30

31

32

33

34

35

36

37

38

39

40

* No enhancement of conductivity in

liquid

* No enhancement of conductivity in

liquid


EnthalpyEnthalpy

Temperature (oC)

En

thal

py(J

/m3 )

800 1000 1200 1400 16004E+09

5E+09

6E+09

7E+09

8E+09

9E+09

1E+10

1.1E+10

1.2E+10


Thermal Linear ExpansionThermal Linear Expansion

Temperature (oC)

TLE

(%)

800 1000 1200 1400-0.02

-0.01

0

0.01

0.02

tle(%)


Mold Heat Flux DataMold Heat Flux Data

0

1

2

3

4

5

0 10 20 30 40 50 60

Kapaj [1]

Wolf fitted Eqn for slag casting: 7.3*t(s)-0.5 [2]

Wolf fitted Eqn for oil casting: 9.5*t(s)-0.5 [2]Thin Slab [3]

Brimacombe fitted Eqn: 2.68-0.222t(s) 0.5 [4]

C LI fitted Eqn for Slab casting: 4.05*t(s)-0.33 [5]

C LI fitted Eqn for Billet Casting -4.7556t-0.504

Lorento fitted Eqn: 1.4*Vc(m/min) 0.5 with 700mm Mold [6]Other Sources: 0.1%C, BilletOther Sources- Slab?

Dwell Time (s)[1] Kapaj N., Pavlicevic M. and Poloni A., 84th Steelmaking Conf. Proc., Baltimore, MD, ISS, p67[2] Wolf M.M., I&SM, V.23, Feb., 1996, p47[3] Park J.K., Samarasekera I.V., and Thomas B.G. et al, 83th Steelmaking Conf. Proc., Warrendale, PA, ISS, p13[4] Brimacombe J.K., Canadian Metallurgical Quarterly, V.15, N.2, 1976, p17[5] Li C. and Thomas B.G. Brimacombe Memorial Symposium, Vancouver, Canada, 2000, p17[6] Lorento D.P. unpublished paper


Instantaneous Heat Flux AssumedInstantaneous Heat Flux Assumed

0

1

2

3

4

5

0 10 20 30 40 50 60

Heat Flux (MW/m2)

Time Below Meniscus (sec.)


Parametric StudyParametric Study

Assume:– Unique heat flux profile down mold– Ideal mold operation to achieve uniform heat flux

around mold parameters– Ideal spray zone managed to produce no change in

surface temperature below mold exitVary:– Casting speed for given section size and mold length

until failure criterion is just exceeded

Assume:– Unique heat flux profile down mold– Ideal mold operation to achieve uniform heat flux

around mold parameters– Ideal spray zone managed to produce no change in

surface temperature below mold exitVary:– Casting speed for given section size and mold length

until failure criterion is just exceeded


Conditions of Parametric StudyConditions of Parametric Study

7381(s120), 10797(s175), 15433(s250)Node Number7200(s120) ,10560(s175) ,15120(s250)Element Number

1459.9090% Solid Temperature (oC) (Damage strain accumulation begins)

1477.0270% Solid Temperature (oC) (Shell Thickness)

1500.72Liquidus Temperature (oC)1411.79Solidus Temperature (oC)1540.0Pouring Temperature (oC)0.001 ~ 0.5Time Step (sec.)

0.1x1.0 (at surface), 1.4x1.0 (at center)Mesh Size (mm x mm)0.3Time of Turning on Ferrostatic Pressure (sec.)0.75 (on both faces)Taper (%/m)600, 800, 1100Total Mold Length (mm)500, 700, 1000Working Mold Length (mm)120x120, 175x175, 250x250Billet Section Size (mm x mm)0.27C, 1.52Mn, 0.34Si, 0.015S, 0.012PMaterial Composition (wt%)


Surface Temperature History Surface Temperature History

DISTANCE-BELOW-MENISCUS(mm)

TEM

PER

ATU

RE(

C)

0 250 500 750 1000600

700

800

900

1000

1100

1200

1300

1400

1500

TEMPERATURE(C) - Horizontal Face CenterTEMPERATURE(C) - Vertical Face CenterTEMPERATURE(C) - Corner

5.0Casting Speed (m/min)

700Working Mold Length (mm)

120x120Section Size (mm x mm)

DISTANCE-BELOW-MENISCUS(mm)TE

MPE

RAT

UR

E(C

)0 250 500 750 1000600

700

800

900

1000

1100

1200

1300

1400

1500

TEMPERATURE(C) - Horizontal Face CenterTEMPERATURE(C) - Vertical Face CenterTEMPERATURE(C) - Corner

Mold Exit





Shell Thickness HistoryShell Thickness History

DISTANCE-BELOW-MENISCUS(mm)SH

ELL-

THIC

KNES

S(m

m)

0 100 200 300 400 500 600 7000

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

SHELL-THICKNESS(mm) - CenterSHELL-THICKNESS(mm) - Corner


SHEL

L-TH

ICKN

ESS(

mm

)

0 100 200 300 400 500 600 7000

5

10

15

SHELL-THICKNESS(mm) - CenterSHELL-THICKNESS(mm) - Corner








Surface Temperature Profile(Mold Exit and Below)

Surface Temperature Profile(Mold Exit and Below)

700Distance below Meniscus (mm)

19.10Time from Meniscus (sec.)




X(mm), Y(mm)

TEM

PER

ATU

RE(

C)

0 10 20 30 40 50 60600

700

800

900

1000

1100

1200

TEMPERATURE(C) - Horizontal FaceTEMPERATURE(C) - Vertical Face

Y(mm), X(mm)TE

MPE

RAT

UR

E(C

)0 10 20 30 40 50 60600

700

800

900

1000

1100

1200

TEMPERATURE(C) - Horizontal FaceTEMPERATURE(C) - Vertical Face







Temperature Contour and Distorted Shape(Mold Exit)

Temperature Contour and Distorted Shape(Mold Exit)

X(mm)

Y(m

m)

0 10 20 30 40 50 600

10

20

30

40

50

60 TEMPERATURE(C)1500.721477.021411.7913501300125012001150110010501000950900

11.16 mm











X(mm)Y(

mm

)0 10 20 30 40 50 600

10

20

30

40

50

60 TEMPERATURE(C)1500.721477.021411.7913501300125012001150110010501000950900

8.10mm


Temperature Contour and Distorted Shape(200 mm Below Mold Exit)

Temperature Contour and Distorted Shape(200 mm Below Mold Exit)

X(mm)

Y(m

m)

0 10 20 30 40 50 600

10

20

30

40

50

60 TEMPERATURE(C)1500.721477.021411.7913501300125012001150110010501000950900

13.81 mm











X(mm)Y(

mm

)

0 10 20 30 40 50 60

0

10

20

30

40

50

60 TEMPERATURE(C)1500.721477.021411.7913501300125012001150110010501000950900

8.10mm


Bulging Shapes(Mold Exit and 200 mm Below Mold Exit

Bulging Shapes(Mold Exit and 200 mm Below Mold Exit

Y(mm), X(mm)

Dis

plac

emen

t(m

m)

0 10 20 30 40 50 60

0.3

0.4

0.5

0.6

U-DISPLACEMENT(mm) - Mold ExitV-DISPLACEMENT(mm) - Mold ExitU-DISPLACEMENT(mm) - 200mm below Mold ExitV-DISPLACEMENT(mm) - 200mm below Mold Exit

Y(mm), X(mm)D

ISPL

ACEM

ENTS

(mm

)0 10 20 30 40 50 60-4

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

0.5

1

U-DISPLACEMENT(mm)V-DISPLACEMENT(mm)








ObservationsObservations

Surface temperature is higher for the higher casting speed cases due to their shorter dwell time in the mold.Surface temperature at the center of the face is higher than that at the corner due to 2D heat extraction at corner.Shell thickness at the mold exit is thinner as the casting speed increasing.The amount of bulging increases as the casting speed increasing. Billet surface shrinks for the 2.20 m/min casting speed case, while bulges around 3 mm for the 5.0 m/min casting speed case.

Surface temperature is higher for the higher casting speed cases due to their shorter dwell time in the mold.Surface temperature at the center of the face is higher than that at the corner due to 2D heat extraction at corner.Shell thickness at the mold exit is thinner as the casting speed increasing.The amount of bulging increases as the casting speed increasing. Billet surface shrinks for the 2.20 m/min casting speed case, while bulges around 3 mm for the 5.0 m/min casting speed case.


Total Strains X(At Mold Exit)

Total Strains X(At Mold Exit)

X(mm)Y(

mm

)0 10 20 30 40 50 600

10

20

30

40

50

60 TOTAL-STRAIN-X(%)10.80.60.40.20

-0.2-0.4-0.6-0.8-1

8.10mm

X(mm)

Y(m

m)

0 10 20 30 40 50 600

10

20

30

40

50

60 TOTAL-STRAIN-X(%)10.80.60.40.20

-0.2-0.4-0.6-0.8-1

11.20 mm












Total Strains X(200 mm Below Mold Exit)

Total Strains X(200 mm Below Mold Exit)

X(mm)Y(

mm

)0 10 20 30 40 50 60

0

10

20

30

40

50

60 TOTAL-STRAIN-X(%)21.510.80.60.40.20

-0.2-0.6-0.8-1-1.5-2

8.10mm

X(mm)

Y(m

m)

0 10 20 30 40 50 600

10

20

30

40

50

60 TOTAL-STRAIN-X(%)10.80.60.40.20

-0.2-0.4-0.6-0.8-1

13.81 mm












Total Strains Y(At Mold Exit)

Total Strains Y(At Mold Exit)

X(mm)Y(

mm

)0 10 20 30 40 50 600

10

20

30

40

50

60 TOTAL-STRAIN-Y(%)10.80.60.40.20

-0.2-0.4-0.6-0.8-1

8.10mm

X(mm)

Y(m

m)

0 10 20 30 40 50 600

10

20

30

40

50

60 TOTAL-STRAIN-Y(%)10.80.60.40.20

-0.2-0.4-0.6-0.8-1

11.20 mm












Total Strains Y(200 mm Below Mold Exit)

Total Strains Y(200 mm Below Mold Exit)

X(mm)Y(

mm

)0 10 20 30 40 50 60

0

10

20

30

40

50

60 TOTAL-STRAIN-Y(%)21.510.80.60.40.20

-0.2-0.4-0.6-0.8-1-1.5-2

8.10mm

X(mm)

Y(m

m)

0 10 20 30 40 50 600

10

20

30

40

50

60 TOTAL-STRAIN-Y(%)10.80.60.40.20

-0.2-0.4-0.6-0.8-1

13.81 mm












Strain History Crack sensitive off-corner subsurface location

Strain History Crack sensitive off-corner subsurface location

DISTANCE-BELOW-MENISCUS(mm)ST

RAI

NS

(%)

TEM

PER

ATU

RE(

C)

0 1000 2000 3000 4000-2

-1

0

1

2

3

4

5

6

7

8

9

10

1400

1450

1500

1550

TOTAL-STRAIN-X(%)PLASTIC-STRAIN-X(%)THERMAL-STRAIN(%)ELASTIC-STRAIN-X(%)FLOW-STRAIN-X(%)TEMPERATURE(C)DAMAGE-CRITERIA3(%)

Brittle Temperature Range


STR

AIN

S(%

)

TEM

PER

ATU

RE(

C)

0 500 1000 1500 2000-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

1400

1450

1500

1550

TOTAL-STRAIN-X(%)PLASTIC-STRAIN-X(%)THERMAL-STRAIN(%)ELASTIC-STRAIN-X(%)FLOW-STRAIN-X(%)TEMPERATURE(C)DAMAGE-CRITERIA3(%)

Brittle Temperature Range

(6.7,17.4)Location (x mm, y mm)




(6.7,17.4)Location (x mm, y mm)





ObservationsObservationsStrains in X and Y directions are mirror imagesThere is little plastic strain developed for the normal casting speed case at the off-corner subsurface location, while substantial amount of plastic strain is built up at the off-corner subsurface location for the high casting speed.High tensile total strain in liquid indicates stretching of the liquid domain by ferro-static pressure, which causes fluid flow filling (ie. “flow strain”).High tensile strain region below mold exit near solidifying front in direction across dendrites is a dangerous location for causing off-corner hot tear cracks.

Strains in X and Y directions are mirror imagesThere is little plastic strain developed for the normal casting speed case at the off-corner subsurface location, while substantial amount of plastic strain is built up at the off-corner subsurface location for the high casting speed.High tensile total strain in liquid indicates stretching of the liquid domain by ferro-static pressure, which causes fluid flow filling (ie. “flow strain”).High tensile strain region below mold exit near solidifying front in direction across dendrites is a dangerous location for causing off-corner hot tear cracks.


Hot Tear Fracture Criterion(Young Mok WON**)

Hot Tear Fracture Criterion(Young Mok WON**)

CTsteelCfornm

fTfTTwhere

T

thresholdDamage

oB

ssB

nB

mc

c

9%27.002821.0,8638.0*,3131.0*)99.0()9.0(

:

,

**

=∆===

=−==∆

∆=

ϕ

εϕε

ε

&

** Critical fracture strain is calculated based on the empirical equation above by Y.M. WON et. al. which is published in Met. Trans. B, Vol. 31B, August, 2000.

cflowinelastic εεε >+Σ )( when occurs Fracture :CriterionCrack Solid 99%Solid 90%


Failure Criterion Evaluation: Failed Points(V = 5.0 m/min)

Failure Criterion Evaluation: Failed Points(V = 5.0 m/min)

0.00700.02646.2160.0073490.00630.007015.496.5830800.00600.007616.706.9830200.00510.014017.586.9829590.00640.009319.936.5927750.00740.011119.656.2127740.00780.009020.556.2127130.00680.009221.726.5926530.00770.012121.456.2126520.00710.014959.105.85890.00910.018160.005.85280.00660.021560.005.5027Damage Threshold Damage Strain YY (mm)X (mm)Node No.


Damage Strain X(At Mold Exit)

Damage Strain X(At Mold Exit)

X(mm)Y(

mm

)0 10 20 30 40 50 600

10

20

30

40

50

60 DAMAGE-CRITERIA3(%)0.10.080.060.040.020

-0.02-0.04-0.06-0.08-0.1

8.10mm

X(mm)

Y(m

m)

0 10 20 30 40 50 600

10

20

30

40

50

60DAMAGE-CRITERIA3(%)

0.10.080.060.040.020

-0.02-0.04-0.06-0.08-0.1

11.20 mm












Damage Strain X(200 mm Below Mold Exit)Damage Strain X(200 mm Below Mold Exit)

X(mm)Y(

mm

)0 10 20 30 40 50 60

0

10

20

30

40

50


0.10.080.060.040.020

-0.02-0.04-0.06-0.08-0.1

8.10mm

X(mm)

Y(m

m)

0 10 20 30 40 50 600

10

20

30

40

50

60 DAMAGE-CRITERIA3(%)0.10.080.060.040.020

-0.02-0.04-0.06-0.08-0.1

13.81 mm












Damage Criterion Y(At Mold Exit)

Damage Criterion Y(At Mold Exit)

X(mm)Y(

mm

)0 10 20 30 40 50 600

10

20

30

40

50

60 DAMAGE-CRITERIA1(%)0.10.080.060.040.020

-0.02-0.04-0.06-0.08-0.1

8.10mm

X(mm)

Y(m

m)

0 10 20 30 40 50 600

10

20

30

40

50


0.10.080.060.040.020

-0.02-0.04-0.06-0.1

11.20 mm












Damage Criterion Y(200 mm Below Mold Exit)

Damage Criterion Y(200 mm Below Mold Exit)

X(mm)Y(

mm

)0 10 20 30 40 50 60

0

10

20

30

40

50


0.10.080.060.040.020

-0.02-0.04-0.06-0.08-0.1

8.10mm

X(mm)

Y(m

m)

0 10 20 30 40 50 600

10

20

30

40

50

60 DAMAGE-CRITERIA1(%)0.10.080.060.040.020

-0.02-0.04-0.06-0.08

13.81 mm












Bulging Histories and Effect of Casting SpeedBulging Histories and

Effect of Casting Speed




DIS

PLAC

EMEN

TS(m

m)

0 1000 2000 3000 4000 5000 6000

-40

-35

-30

-25

-20

-15

-10

-5

0

U-DISPLACEMENT(mm)V-DISPLACEMENT(mm)

Vc = 2.2m/min Vc = 4.6m/min

Vc = 4.8m/min

Vc = 5.0m/min

Vc = 6.0m/min

Vc = 10.0m/min

0

10

20

30

40

50

2 3 4 5 6 7 8 9 10

Maximum Bulging V (mm)Maximum Bulging U (mm)

Casting Speed (m/min)


Maximum Bulging vs Casting Speed(Working Mold Length: 500 mm)


0

20

40

60

80

100

120

2 3 4 5 6 7

Maximum Bulging vs. Casting Speed(Section = 175x175mm, Working Mold Length = 500mm)

Maximum Bulging U (mm)Maximum Bulging V (mm)


0

5

10

15

20

2 3 4 5 6 7 8 9




0

2

4

6

8

10

12

14

0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4







0

10

20

30

40

50

60

70

80

1 1.2 1.4 1.6 1.8 2 2.2 2.4




0

10

20

30

40

50

2 3 4 5 6 7 8 9 10




0

1

2

3

4

5

6

7

2 2.5 3 3.5 4 4.5







0

10

20

30

40

50

60

70

80

0.5 1 1.5 2 2.5 3 3.5 4 4.5




0

5

10

15

20

25

30

35

40

2 2.5 3 3.5 4 4.5




0

2

4

6

8

10

12

2 3 4 5 6 7 8 9 10





Critical Casting SpeedCritical Casting Speed

1

2

3

4

5

6

7

100 120 140 160 180 200 220 240 260

(WML = 500mm)(WML = 700mm)(WML = 1000mm)

Section Size (mm x mm)


Stress Z(At Mold Exit)Stress Z

(At Mold Exit)

X(mm)Y(

mm

)0 10 20 30 40 50 600

10

20

30

40

50

60 STRESS-Z(MPa)1086420

-2-4-6-8-10

8.10mm

X(mm)

Y(m

m)

0 10 20 30 40 50 600

10

20

30

40

50


-2-4-6-8-10

11.20 mm












Stress Z(200 mm Below Mold Exit)

Stress Z(200 mm Below Mold Exit)

X(mm)Y(

mm

)0 10 20 30 40 50 60

0

10

20

30

40

50


-2-4-6-8-10

8.10mm

X(mm)

Y(m

m)

0 10 20 30 40 50 600

10

20

30

40

50


-2-4-6-8-10

13.81 mm












Damage Strain Z(At Mold Exit)

Damage Strain Z(At Mold Exit)

X(mm)

Y(m

m)

0 10 20 30 40 50 600

10

20

30

40

50

60 DAMAGE-CRITERIA2(%)0.10.080.060.040.020

-0.02-0.04-0.06-0.08-0.1

X(mm)Y(

mm

)0 10 20 30 40 50 600

10

20

30

40

50

60 DAMAGE-CRITERIA2(%)0.10.080.060.040.020

-0.02-0.04-0.06-0.08-0.1












ConclusionsConclusions

Parametric study was performed to investigate the maximum casting speed for different square sections sizes and mold lengths with uniform heat flux around the mold parameters.Excessive bulging below mold exit may generate subsurface of corner longitudinal cracks due to hinging.Bulging criterion (4~10 mm maximum) and the hot tearing damage criterion indicate the same critical casting speed due to sub-mold bulging for certain section size and mold length.Excessive tensile stresses built up at the billet corner within the mold may generate transverse corner cracks due to high corner cooling.

Parametric study was performed to investigate the maximum casting speed for different square sections sizes and mold lengths with uniform heat flux around the mold parameters.Excessive bulging below mold exit may generate subsurface of corner longitudinal cracks due to hinging.Bulging criterion (4~10 mm maximum) and the hot tearing damage criterion indicate the same critical casting speed due to sub-mold bulging for certain section size and mold length.Excessive tensile stresses built up at the billet corner within the mold may generate transverse corner cracks due to high corner cooling.


Future WorkFuture Work

The influence of mold distortion, taper, imperfect contact between mold wall and billet surface, as well as sub-mold cooling pattern to the maximum casting speed will be investigated.

The influence of mold distortion, taper, imperfect contact between mold wall and billet surface, as well as sub-mold cooling pattern to the maximum casting speed will be investigated.

Documents

Maximum Casting Speed for Continuous Casting Steel Billetsccc.illinois.edu/s/2001_Presentations/cli1/Cli_presentation... · University of Illinois at Urbana-Champaign • Metals Processing