六流小方坯中间包堵流浇注的数值模拟研究

Numerical study on strand-blocking operation of a six-strand square billet tundish

在连铸生产中,时常会因钢水供应不足或设备故障对生产节奏调配而进行堵流操作。以某厂六流小方坯中间包为对象,采用数值模拟的方法,研究了其在堵1流和堵2流浇注的情况下的流场和温度场及夹杂物的去除率,来确定最佳的堵流操作,为现场生产提供理论指导。结果表明,堵1流和堵2流情况下,随着堵流从边缘靠近冲击区,中间包整体平均停留时间分别延长43.3、109.3 s,活塞区体积增加1.3%、12.3%,死区体积降低0.4%、4.1%,各流流动的一致性都得到了提高,中间包整体温度也更均匀,5、10、20和40μm夹杂物去除率变高,但是80和100μm夹杂物去除率变低。堵1流时,选第3流或第4流最佳;堵2流时,选第3流和第4流最佳。

During the continuous casting production, the strand-blocking operation is often carried out due to the insufficient supply of molten steel or equipment failure to adjust the production rhythm. The flow, temperature field and inclusion removal rate in a six-strand bloom casting tundish under the conditions of blocking one strand and two strands were numerically investigated to determine the optimum strand-blocking operation, which can provide theoretical guidance for industrial production. The results show that in the case of blocking one strand and two strands, with the blocked strands move from the edge of the tundish to the impact zone, the average residence time of the tundish increases by 43.3 s and 109.3 s, the volume fraction of the plug zone increases by 1.3% and 12.3%, while the volume fraction of the dead zone decreases by 0.4% and 4.1%, respectively. The flow consistency among the strands is apparently enhanced, and the temperature of liquid steel in the tundish is more uniformly distributed. Furthermore, the removal rates of non-metallic inclusions with the diameters of 5, 10, 20 and 40 μm increase, while the removal rates of inclusions with diameters of 80 and 100 μm decrease. When blocking only one strand, the third strand or the fourth strand is the optimum choice. When blocking two strands, it is best to choose both the third and the fourth strands.