重轨钢连铸结晶器电磁搅拌技术应用研究

Research on Mold Electromagnetic Stirring Technologies for Bloom Continuous Casting of Heavy Rail

针对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强度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,中心碳偏析指数≤1．05,连铸坯轧成重轨的内部质量和力学性能能够满足350 km/h高速铁路用钢轨的要求。

Metallurgical results of mold electromagnetic stirring （M- EMS） in continuous casting previous employed at continuous bloom caster for heavy rail steel was not fully achieved. Therefore, experiments for optimizing process parameters of M - EMS for heavy rail steel was carried out. In order to analyze the influence of the current intensity on internal quality of heavy rail bloom, such as center looseness, central segregation and the ratio of equiaxed zone, the effects with different current intensity were investigated. On the basis, the M - EMS scheme most suitable for heavy rail steel was developed, which improves internal quality of heavy rail bloom obviously. The operation shows that the area ratio of equiaxed zone is increased from 18.8% to 36.2 %, center looseness is ≤ 1.5, central segregation and shrinkage cavity are ≤1.0, meanwhile, the cen- tral segregation index of carbon is ≤1.05. Internal quality and mechanical performance of the rails produced from continuously cast blooms have met the requirement of 350 km/h high - speed tracks.