Design and Plant Experience Using an

Advanced Pouring Box to Receive and

Distribute the Steel in a Six Strand Tundish

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)

Tundish with Baffles

Objetives

Improving flow conditions during start, steady

state and ladle change, aiming at better

ceanliness of the steel, particulary for inner

strands.

Start of the Sequence

Ladle Change

Hot

Water

Cold

Water

Ladle Change - Slag Simulation

Ladle Change - Slag Simulation

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

Co

nc

en

tra

ci

n a

dim

en

sio

na

l

Lnea 1 y 6

Lnea 2 y 5

Lnea 3 y 4

Residence Time and Volume Type

Tundish with Baffles, Steady State

Strand residence

time mn.

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

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

Tundish with Turbulence Inhibitor

dead volume

short circuit

Shroud

APB

Advanced Pouring Box

Optimization of Advanced

Pouring Box

00,2

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

Time (adimentional)

Conc

entrat

ion

(adi

men

tiona

l)

Lnea 1

Lnea 2

Lnea 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

Time (adimentional)

Con

cent

ratio

n (a

dim

entio

nal)

Lnea 1

Lnea 2

Lnea 3

Baffles

APB

RTD Curves

APB vs. Baffles, Steady State

Baffles

APB

050

100

150

200

Minimum Residence Time Medium Residence Time

Tim

e [s] Baffles

APB

0

10

20

30

40

50

60

% Plug Volume % Dead Volume

%

Baffles

APB

APB vs. Baffles, Steady State

Tundish with APB, Ladle Change

Math Modeling

Speed Fields

Baffles APB

Math Modeling

Turbulent Kinetic Energy

Baffles APB

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

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

Baffles

APB

Continuous Temperature Measurement

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