连铸工艺生产重轨钢的工业试验

Industrial experiment on production of heavy rail steel with continuous casting process

应用电炉冶炼→LF精炼→VD真空脱气→圆坯连铸工艺进行了重轨钢生产现场试验。通过应用无铝脱氧工艺和真空脱气装置、控制浇铸过程中钢液过热度和拉速改善了铸坯内部质量,生产的重轨钢中w(T.O)≤20×10-6,A类夹杂在1.5级以下,B类在1.5级以下,C类在1.0级以下,D类在1.0级以下,铸坯一般疏松在1.0级以下,中心疏松在1.5级以下,点状偏析在1.0级以下,等轴晶率在40%以上;优选结晶器电磁搅拌工艺参数和重轨钢连铸保护渣配方,确保了铸坯表面质量,铸坯表面无裂纹、气孔、结疤、折迭、凹坑和夹渣等缺陷,铸坯表面无清理率在90%以上。

The quality control test of rail steel production by EAF steelmaking→LF refining→VD degassing→round bloom concasting process is briefly discussed. The internal quality and non-metallic inclusions of round bloom were improved by application of the Al free deoxidization process and vacuum degassing device and proper control of the overheat of the hot metal and the drawing speed in the process of casting. In the heavy rail steels produced in this way the T[O]≤20 ×10^-6 and inclusions Class A≤1.5,Class B≤ 1.5, Class C≤1.0, Class D≤1.0, general porosity≤1.0, central porosity≤1.5, the scattered segregation ≤1.0 and the ratio of equiaxed crystal zone ≥40 %. By optimization of the mould electromagnetic stirring process parameters and proper design of the ingredient of the mould flux for the heavy rail steel the surface quality of the bloom can be ensured and the surface defects of the round blooms such as surface crack, blowhole,scar, laminar,pit and slag entrapment be removed and the surface defect free round blooms exceed over 90%.