电磁搅拌对石油管用圆坯内部质量的改善

针对P110级石油管用圆坯27Mn2Cr钢连铸坯凝固组织差、中心缩孔严重等缺陷,结合实际生产工艺进行分析,发现不适宜的电磁搅拌工艺及与拉速匹配性差是引起上述问题的主要原因。因此,对结晶器和末端电搅强度进行测量及优化,同时建立?220 mm规格圆坯凝固传热模型,以确定合理的连铸机拉速。通过分析表明,拉速由1.30 m/min提高至1.70 m/min并搭配合理的电搅工艺,铸坯中心等轴晶所占比例由16%提高至25%,中心缩孔消失;同时铸坯内部碳偏析指数范围由0.938~1.062缩小至0.951~1.038,改善了石油套管用圆坯的内部质量。

Improvement of internal quality for round billet of petroleum pipe by electromagnetic stirring

In view of defects such as poor solidification structure and serious central shrinkage of 27Mn2Cr steel round billet for P110 petroleum pipe, the analysis was carried out combined with the actual production process. It can be concluded that inappropriate electromagnetic stirring process and poor matching with casting speed are the main reasons for the above problems. Therefore, the intensity of mold and final electromagnetic stirring were measured and optimized, and the solidification heat transfer model of ?220 mm round billet was established to determine the reasonable casting speed of continuous caster. The analysis shows that when casting speed is increased from 1.30 m/min to 1.70 m/min, with reasonable electromagnetic stirring process, the proportion of equiaxed crystal in the billet increased from 16% to 25%, and the central shrinkage disappears. At the same time, the range of carbon segregation index in the billet is changed from 0.938-1.062 to 0.951-1.038, which improves the internal quality of round billet for petroleum pipe.