| The non-metallic inclusions in steel will reduce the quality of steel and can't meet the requirements of clean steel production.Induction heating tundish can make up for the temperature drop caused by heat loss of molten steel,optimize the flow field and temperature field,but the removal effect of inclusions needs to be further improved.The venturi channel type liquid steel filter uses the contraction and expansion of the venturi tube section to change the flow trajectory of liquid steel,increases the flow rate of liquid steel at the throat section of the venturi tube,makes the liquid steel fully mixed,and makes the small size inclusions have more opportunities to collide,adhere and grow up,so as to improve the removal rate of non-metallic inclusions.In this paper,a venturi channel filter is designed to replace the original tundish straight pipe channel.Three factors,including throat diameter,throat position and taper angle,are selected to design nine different sizes of venturi structures by orthogonal method.Numerical simulation method is used to analyze the distribution of flow field and temperature field in tundish.The optimal design scheme of venturi channel is determined,and the removal rate of non-metallic inclusions of various sizes is mainly calculated.Under the condition of 1.2t/min and 1.5t/min,the flow field of tundish and venturi channel tundish in the straight pipe channel is simulated.Compared with the straight pipe tundish,the venturi channel tundish can better uniform flow field,increase the flow strand of pouring area to free liquid level,and the distribution of streamline in the tundish is more orderly and the short circuit flow is obviously reduced.Combined with the analysis of flow field and temperature field,it is considered that scheme 9 is the best when the steel flow rate is 1.2t/min,the maximum temperature difference in the ladle is reduced from 34.5K to25.8K,and the temperature difference at the outlet section is reduced from 2.8K to 1.2K.When the steel flow rate is 1.5t/min,scheme 6 is the best,the maximum temperature difference in ladle is reduced from 30.8K to 21.6K,and the temperature difference of outlet section is reduced from 2.1K to 1.01 K.It is found that the removal rate of inclusions is related to the diameter of inclusions.For 80 ?m and above large size inclusions,the removal rate can reach 96%;for 10 ?m small size inclusions,the removal efficiency is about 30%,which is more than 18% higher than that of straight tube channel tundish.The tundish with straight tube channel has little effect on 5 ?m and 1 ?m inclusions,and the removal rate is close to 30% after venturi channel is used.It shows that venturi channel filter has obvious effection on removing small size inclusions. |
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