结晶器电磁搅拌改善重轨钢连铸坯内部质量的试验研究

Improvement on Internal Quality of Heavy Rail Steel Bloom by Mold Electromagnetic Stirring

针对攀钢大方坯连铸机投产初期重轨钢连铸电磁搅拌冶金效果不明显的问题,开展了优化重轨钢连铸结晶器电磁搅拌工艺参数的现场试验,对比研究了电磁搅拌电流对重轨钢铸坯中心疏松、中心偏析、等轴晶率等内部质量的影响,制定了满足攀钢重轨钢连铸工艺要求的电磁搅拌工艺制度。生产应用表明,重轨钢连铸坯内部质量明显提高,铸坯中心区等轴晶率由18.8%增至36.2%,中心疏松≤1.5级,中心偏析≤1.0级,中心缩孔≤1.0级,连铸坯轧成重轨的内部质量和力学性能能够满足时速350 km高速铁路用钢轨的要求。

Metallurgical targets of using mold electromagnetic stirring （M-EMS） in bloom continuous casting of heavy rail steel was not fully achieved in the pact. Therefore, experiments for optimizing process parameters of MEMS for heavy rail steel bloom casting was performed to analyze the influence of the current intensity on the internal quality of bloom, such as center looseness, central segregation and the ratio of equiaxed zone and the a most suitable M-EMS scheme was developed. The production results show that in the bloom the ratio of equiaxed zone was increased from 18.8% to 36.2%, center looseness was ≤1.5, while, central segregation and shrinkage cavity were ≤1.0. The internal quality and mechanical quality of the rails from blooms meet the requirements of high speed 350 km/h tracks.