320 mm×410 mm大方坯连铸重轨钢质量改进与应用

为了提高大断面重轨钢连铸坯内部质量,满足钢轨探伤要求,针对大断面生产重轨钢铸坯宏观偏析及中心疏松较难控制的难点,采用合适的二冷制度、凝固末端电磁搅拌技术、动态轻压下控制技术、钢水过热度控制以及拉速控制等技术措施,开发了攀钢320 mm×410 mm大方坯连铸重轨钢生产工艺。生产的大方坯重轨钢连铸坯中心等轴晶率稳定控制在40%以上,中心疏松控制在不大于0.5的比例为91%以上,中心偏析在0.5级的比例为87%以上,等柱晶率不小于40%的比例为100%,碳偏析指数控制在0.95~1.07,铸坯及钢轨质量较好,满足了标准要求并通过了CRCC认证。

Improvement of quality of 320 mm×410 mm bloom in continuous casting of railway steel and its application

In order to improve the inner quality of bloom of railway steels and meet the requirement of rail flaw inspec-tion. Appropriate secondary cooling system,F-EMS,dynamic soft reduction technology,control of molten steel super-heat and casting speed were put forward to solve the segregation and center porosity of railway steel bloom in current study. The producing technology of 320 mm × 410 mm continuous bloom of railway steel was established based on the above. The center equiaxial crystal rate of bloom was steadily controlled not less than 40%. The rate of center porosity that was not more than 0.5 level was above 91%. The rate of center segregation that was not more than 0.5 level was above 87%. Carbon segregation index of bloom ranged from 0.95 to 1.07. The quality of bloom and steel rail produced is better and can meet the requirement of CRCC.