脉冲电流对钢液凝固过程中夹杂物迁移行为的影响

在钢液凝固过程中施加脉冲电流,通过观察和分析凝固试样中夹杂物的形貌、数量、尺寸和分布状态等,以研究施加脉冲电流对钢中夹杂物迁移行为的影响。结果表明,在脉冲电流的影响下,钢液凝固初期形成的晶核会发生脱落而形成结晶雨;在晶核下落过程中,钢中夹杂物也会随之向下部迁移。随着脉冲电流强度的逐渐增加,钢锭上、中部夹杂物逐渐减少,晶粒尺寸变小。在本试验条件下,当电流强度为56.6 A/cm2 时,钢锭上、中部夹杂物的总面积和总数量分别比未施加脉冲电流时的降低46.9% 和35.6%。对于夹杂物含量要求较高的钢种而言,在钢锭凝固过程中施加脉冲电流,控制结晶雨的形成和迁移过程不失为一种有效去除钢中夹杂物、提高钢锭质量的技术手段。

Effect of electric current pulse treatment on migration behavior of inclusions during solidification in steel

Electric current pulse (ECP) treatment was applied to steel during solidification process and its effect on the migration behavior of inclusions was investigated by observing and analyzing the morphology, quantity, size and composition of inclusions. The results show that under the influence of ECP treatment, the crystal nucleus falls off at the initial stage of solidification, which results in the formation of crystal rain. During the falling process of the crystal nucleus, the inclusions also migrate downward. With the increase of current density, the number of inclusions in upper and middle regions of ingots and the size of grain decrease. Compared with that without ECP treatment, it reduces the number and the area of inclusion in upper and middle regions of ingots by 46.9% and 35.6%, respectively, when the current density is 56.6 A/cm2 under the current experimental condition. For the steel with high requirement of inclusion content, applying ECP treatment to control the formation and migration of crystal rain during ingot solidification is an effective technology to remove inclusions in steel and improve ingot quality.