Based on water and math modeling work, a refractory device wasdesigned aiming to improve the liquid steel f[ow in the tundish of a billet, bloom and minislab caster. The simulation work took into account sequence start, Iadle change and steady state. The device improved flow behavior for the inner strands and helped minimizing slag emulsification and the contact of the steel with the air, especially at ladle change. Better inclusion counts and temperature homogeneity throughout the sequence were obtained when using APB in the tundish.

1. Design and Plant Experience Using an
Advanced Pouring Box to Receive and
Distribute the Steel in a Six Strand Tundish

2. Steel Plant
DRI Plant 1,000,000 tpy DRI
3 EAF x 110 t 1,500,000 tpy
2 LF x 110 t
2 CC Machines x 6 strands
A: billets, blooms and minislabs, oil or powder
casting, carbon and low alloy steels
B: 120 x 120 mm sq. billets, oil casting, carbon
steels (0,05 to 0,8 % C)

3. Tundish with Baffles

4. Objetives
Improving flow conditions during start, steady
state and ladle change, aiming at better
ceanliness of the steel, particulary for inner
strands.

5. Start of the Sequence

6. Ladle Change
Hot
Water
Cold
Water

7. Ladle Change - Slag Simulation

8. Ladle Change - Slag Simulation

9. RTD Curves, Tundish with
Baffles, Steady State
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0 0.5 1 1.5 2 2.5
Tiempo adimensional
Concentraciónadimensional
Línea 1 y 6
Línea 2 y 5
Línea 3 y 4

10. Residence Time and Volume Type
Tundish with Baffles, Steady State
Strand residence
time mín.
s
residence
time med.
s
%
plug
flow
%
perfect
mix
%
dead
volume
1 & 6 58 190 12 56 32
2 & 5 24 161 5 52 43
3 & 4 10 126 2 43 55

11. Results of Tundish with Baffles
 better start when using slidegate
 slag emulsification during ladle changes
 change in flow pattern during ladle changes
 short circuit for strands # 3 and # 4
 second peak in RTD curves, strands 2 to 5
 low plug flow volume, strands 2 to 5

12. Tundish with Turbulence Inhibitor
dead volume
short circuit

13. Shroud
APB
Advanced Pouring Box

14. Optimization of Advanced
Pouring Box

15. 0
0,2
0,4
0,6
0,8
1
1,2
1,4
1,6
1,8
2
0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1
Tim e (adim entional)
Concentration(adimentional)
Línea 1
Línea 2
Línea 3
0
0,5
1
1,5
2
2,5
3
3,5
4
0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1
Tim e (adim entional)
Concentration(adimentional)
Línea 1
Línea 2
Línea 3
Baffles
APB
RTD Curves

16. APB vs. Baffles, Steady State
Baffles
APB

17. 0
50
100
150
200
Minimum Residence Time Medium Residence Time
Time[s]
Baffles
APB
0
10
20
30
40
50
60
% Plug Volume % Dead Volume
%
Baffles
APB
APB vs. Baffles, Steady State

18. Tundish with APB, Ladle Change

19. Math Modeling
Speed Fields
Baffles APB

20. Math Modeling
Turbulent Kinetic Energy
Baffles APB

21. Plant Experience 1
 trouble during tundish assembly
 crack formation during APB preheating
 problems with shroud movement during ladle
opening
 improved steel flow during start of sequence

22. Plant Experience 2
 elimination of start up problems
 good abrassion resistance in sequences up to 7
heats
 better inclusion counts in carbon steel billets for
bars
 better thermal homogeneity along the sequence

23. Baffles
APB
Continuous Temperature Measurement

24. Conclusions
 APB is a good solution for long, narrow
multistrand tundishes still operating in many
billet machines
 better flow conditions for inner strands
(residence time, plug flow, no second peak)
 no slag emulsification during ladle change
 lower inclusions counts
 temperature uniformity along the sequence