Crack Paths 2012

An area between isoliquidus and isosolidus is the so-called mushy zone. Table 1

contains the individual parameters of both melts 3 and 4.

Table 1 The parameters characterizing the concasting of melt 3 (quality A)

and melt 4 (quality B)

Symbol Units

It#em Parameter

A – melt 3 B – melt 4

0.0130

0.0126

1 Pouring speed

w [m.s-1]

2 Dynamic viscosity

K [m-1.kg.s-1]

0.00570 TL 0.00562 TL

0.00772 TS 0.00615 TS

K = U.Q [m-1.kg.s-1]

7560.7

7600.9

3 Density

U

[kg.m-3]

259×103

4 Latent heat of the phase change

L [m2.kg.s-2]

246×103

cp

632.6

611.0

[m2.s-2.K-1]

5 Specific heat capacity

[m]

0.006r0.003 0.006r0.003

6 Mouldoscillation amplitude

'S

[s-1]

1.533

7 Oscillation frequency

f

1.533

1427.0

8 Solidus temperature

T S

[°C]

1480.6

1493.9

9 Liquidus temperature

T L

[°C]

1512.3

10 Difference between the liquidus and solidus t mpera ur s

66.9

31.7

T L – T S

[°C]

21.07

11 Max. length of the isosolidus curve from th level*

m

19.72

maxSh

19.92

12 Min. length of the isosolidus curve from the level**

m

18.69

minSh

14.50

13 Max. length of the isoliquidus curve from the level*

m

16.20

maxLh

13.70

14 Min. length of the isoliquidus curve from th level**

m

15.20

minLh

mushy F

15 The area of the mushy zone on half of the cross-section of the breakout +

m2

0.05366

0.04100

16 The surface temperature of the slab++

°C

934

1097

T surf

Note (continued from table above): *) of the steel inside the mould to a position

0.650 m from the edges of the 1.53 m wide slab; **) of the steel inside the mould to the

+) the overall area of half of the cross-section is Fslab = 0,19125 m2 ;

centre of the slab;

++) in the material 1 5 m maround the groove (Fig. 2). The data in Table1 were

established a) on the caster after breakout; b) from archived on-line results of the

temperature model; c) by off-line modelling of the temperature field of melts 3 and 4

[5].

D I M E N S I O N L ECSRSITERIA

If the method of dimensionless analysis is applied for assessing and reducing the

number of parameters in Table 1 in the first approximation, then it is possible to express

the level of risk of breakout as a function of the five dimensionless criteria contained in

Table 2 (units m, kg, s, K).

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