中间包吹氩去除钢水夹杂物

通过现场实验,研究了中间包吹氩位置和氩气流量对钢水洁净度的影响,重点探讨了在注流区吹氩对钢水洁净度的影响.结果表明:在T型中间包注流区内进行合适流量吹氩可提高钢水洁净度,在浇铸区拐角处和塞棒附近吹氩对钢水洁净度没有明显的影响;在注流区内吹氩,合适的氩气流量为6L·min^-1,与不吹氩相比,钢中总氧降低率和夹杂物的去除率均可提高10%左右,但15L·min^-1的大流量吹氩将会显著增加钢中总氧和大型夹杂物数量.分析认为:注流区内大的湍流强度可将氩气泡击碎成弥散小气泡,大量小气泡在钢液中上浮,不但提高了气泡捕捉夹杂物的概率,而且增加了夹杂物之间的碰撞机会,其结果是增大了夹杂物的粒径,促进了夹杂物的上浮去除;同时,注流区离水口距离最远,在注流区吹氩,碰撞长大的夹杂物有更长的时间上浮排出.以上两个因素的共同作用,使得在注流区吹氩对去除钢水夹杂物有显著效果.

Inclusions removal in a tundish with argon purging

The effect of argon purging site and argon flow rate in a tundish,in particular argon purging in injection flow area,on steel cleanliness was investigated by field test.The results show that bubbling at injection flow area with suitable argon flow can improve steel cleanliness,while bubbling at the corner site in casting area and nearby the stopper has no obvious effect on steel cleanliness.The suitable argon flow rate is 6 L·min^-1 when purging at injection flow area,and compared with no argon bubbling,the removal rate of total oxygen and inclusions in steel can be decreased about 10%.But large argon flow with 15 L·min^-1 will obviously increase total oxygen and inclusions in steel.Inclusions removal in the argon purging tundish may be explained as that when argon purging at injection flow area,bubbles will be smashed into a smaller size by the strong turbulence intensity.A large number of diffusive bubbles in molten steel not only accelerate the collision between inclusions,but also increase the probability of bubbles to capture inclusions,which result in the increase of inclusion size and accelerating inclusions floating up and being removed.On the other hand,the distance from injection flow area to the tundish nozzle is the longest,and when argon purging at injection flow area,the grown-up inclusions have the longest time to be removed from steel.These two factors make purging at injection flow area have significant impact on inclusions removal.