重轨钢连铸的质量控制

QUALITY CONTROL OF CONTINUOUSLY CAST ROUND OF RAIL STEEL

分析了冶炼、精炼、连铸工艺流程生产高质量重轨钢的工艺技术 ,并应用电弧炉冶炼— L F精炼— VD真空脱气—圆坯连铸工艺成功地浇注出 PD3重轨钢连铸圆坯。铸坯表面无裂纹、气孔、结疤、折迭、凹坑和夹渣等缺陷 ,铸坯表面无清理率 >90 % ,铸坯中心疏松≤ 1.0级 ,中心缩孔≤ 1.0级 ,中心碳偏析指数≤ 1.0 8,等轴晶率≥ 5 0 %。由连铸圆坯轧成的重轨 ,质量和性能基本满足时速 2 0 0 km高速铁路用钢轨的要求。

Based on an analysis of the quality control of rail steel production from steelmaking, refining to continuous casting, the route of EAF steelmaking—LF refining—VD degassing—round continuous casting was established, and experimental PD3 rounds were successfully produced. The round surface was free from cracks, porosity, scars folds concavity and entrapped scums and the rate of defect-free rounds exceeded 90 %. The index of central porosity and shrinkage cavity was ≤1.0 . The index of carbon central segregation was ≤1.08, and the ratio of equiaxed zone was ≥50 %. The quality and performance of the experimental rails met the requirements of high-speed 200 km/h tracks.