70钢小方坯芯部质量优化

Center quality optimization of No.70 steel billet

建立小方坯连铸凝固传热模型,通过测温和射钉试验校核模型,模型计算结果与测温和射钉试验结果间的相对误差分别为0.1%和0.64%,说明模型能够有效反映小方坯连铸的凝固传热情况。提高拉速后,铸坯的中心偏析和疏松加重。为优化高拉速下连铸坯的中心质量,依据模型计算结果及前人安装经验,将末端电磁搅拌安装装置由原来距离结晶器弯月面6.4 m处调整到6.9 m处。最终连铸坯低倍试样中疏松和偏析点减少,碳偏析度范围由0.90~1.15优化为0.95~1.08,连铸坯芯部质量得到明显改善。

The solidification heat transfer model of continuous casting billet was established and checked by the temperature measurement and nail shooting test. The relative errors between the model calculation results and the temperature measurement and nail shooting test results were 0.1% and 0.64%, respectively, indicating the model could reasonably reflect the solidification heat transfer of billet in the continuous casting process. After increasing the drawing speed, the center segregation and looseness of billet increased. In order to optimize the center quality of billet at high casting speed, combined with the calculation results of the model and other installation experiences, the final electromagnetic stirring device was adjusted from 6.4 m to 6.9 m away from the mold meniscus. The porosity and segregation point of continuous casting billet were reduced, the range of carbon segregation index was reduced from 0.90-1.15 to 0.95-1.08. Finally, the central quality of continuous casting billet was improved obviously.