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Förslaget inkom 2005-02-07

Melt flow control in a continous casting process (gh)

PART 1. Preliminary studies
F10: Summery of early research works.
F20: Literature survey
PART 2. Experimental work
F10: Water-Modelling study
F20: Temperature measurements
F30: Theroretical study
PART 3. Numerical simulation
PART 4. Casting trial
F10: Nozzle design
F20: Casting trials

1. General description

The velocity distribution of molten copper contained within the solidifying shell of a continous casting machine is very influential on the distribution of inclusion particle, which is important to the internal cleanliness and quality of the copper. Moreover, higher casting speed leads to higher meniscus turbulence and vortex formation resulting in entrainment of casting powder in to the liquid. In addition the flow patern has an impact on heat transfer to the shell during the critcal initial stages of solidification [1-5].
On the other hand, tundish, working as a buffer and distributor of liquid metal between the furnace and mould, plays a key role in affecting the performance of the casting productivity and also quality. Liquid flow and the temperature distribution are the basic factors govering operation of the tundish process [6-9(1,2)].
With the growth of continous casting, a large number of studies have been reported about the fluid flow inside both the mold and tundish [10-12]. Both theroretical and experimental works have been made to assess the flow pattern inside the mold and tundish. Matsushita et al [13, (3)] studied the free surface fluctuation in the actaul system to find out the relationship between the surface wave motion of molten steel near the mold wall during casting and mold oscillation. They obseved the meniscus of the molten steel directly through a quartz glass window mounted on the mold wall. They concluded that the meniscus is not stationary but fluctuates as those of mould oscillation. Later, Andrzejewski et al [14] studied a full-scale water model to find out the flow pattern, liquid-velocity profile, and gas injection inside the continous steel casting mold. Based on their flow pattern studies, they recommended an optimum operating condition in terms of casting rate, immersion depth and gas injection rate. However, little attention has been paid to the disturbance at the meniscus.

The present work reports the melt-flow study which will ultimately be applied to predict and understand the effect of different design variables on the fluid flow in the mould. The result will be used to develop a mathematical model of the flow pattern in the liquid pool, and thereby to determine how molten copper is distributed through the inlet system.

To have a better control on the casting process, development of accurate and efficient flow control are needed. Two different objectives can be considered:

4. Experiments conducted using a transparent plastic water model of the system aiming to investigate the effects of the design variable of the inlet nozzle jets and operating parameter in adjusting the tundish/ nozzles on the flow pattern.

5. To use a mathematical model of the flow pattern in the liquid pool, and thereby to determine how molten copper is distributed below the nozzles. To verify acceptable accuracy of the model, its predictions will be compared with experiments performed earlier in water model.

2. Target

The physical/mathematical model will ultimately be applied to predict and understand the effects of different variables on the melt flow and finally to have a better control on the casting process. In practice, instruction for modification of the existing inlet system or (depends to the results of the research work) a new set of inlet nozzle system will be preposed


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