Study On Flow Control Device In Six-strand Tundish

This paper bases on studying a six-strand billet continuous casting tundish of Lianyuan Iron and Steel Co. The physical and mathematical model have been done by using an organic glass model with the ratio of 1:3 and PHOENICS code, to study the fluid flow characteristics in the tundish under the flow control devices of A and B type baffle which are being used in work-site and the new designed baffles of C type, D type and E type, and a kind of special impact pad. By analysing the average residence time in the tundish and RTD curves under different conditions, calculating the asymmetrical degree and floating ratio of inclusion, and contrasting of velocity distributing in the tundish, the results are obtained as follows:(l)The pound region volume of the old design baffle A type is too small, the liquid steel can't mix sufficiently. The dead volume and asymmetrical degree is big. The pound region volume of the baffle B type is bigger than the A type, and the liquid steel mix more sufficiently. This type has some strongpoints but the direction of the holes isn't suit, which may result in short-circuit in 3#(4#) stand and impact the stopper. The temperature's difference among the stands is still huge.(2) The pound region volume of the baffle C type is still too small, so the liquid steel can't mix sufficiently, and the average residence time in the tundish is short. But the difference of average residence time among stands is small, which means the fashion of the holes is suitable.(3) The baffle D and E type retain the shape of B type, and adopt the fashion of the hole of C type. The average residence time in the tundish of the No.43 46 48 flow control scheme of the D type baffle and the No.40 50 flow control scheme of the E type baffle all exceed 350 seconds, and the difference is only 32 seconds. The asymmetrical degree is low. Floating rate of inclusion is high and equality. The baffle has a simple shape and reliable capability, and is convenient for installing, can be used in fact.(4) Dam can made the liquid steel rush up and mix sufficiently in the pound region. It is in favor of prolonging the average resident time and floating of conclusion. When the dam is used in casting region, it caneliminate the short-circuit in NO 2#(5#) stand and increase the volume of the plug flow.(5) The special impact pad makes the liquid steel rush up in the pad, which is not only benefit for the mixture of liquid steel and floating of conclusion, but also reduce the rush to the back-wall and baffle, which can prolong theirs using life.(6) This paper uses the weighted mean method to calculate the volume of the plug flow. The respond-time and peak-time of the whole tundish are calculated according to the tracer's quantity of every stand. The result is more nicety than the arithmetical average method.(7) This paper calculates the floating ratio of inclusion by combinational mode and the RTD curves. Result of the later is more coincident with the reality. For multi-strand tundish, the later method can calculate the conclusion's float ration of every strand, which is very useful to compare the effect of different baffle.