铁道车辆用车轴钢夹杂物分析及改善措施

Analysis and Improvement Measures of Inclusions in Axle Steel for Railway Vehicles

通过金相显微镜、扫描电镜和能谱仪观察了铁道车辆用车轴钢中夹杂物形貌,并分析了其成分,提出了工艺优化方案,研究了优化工艺对夹杂物的去除效果。结果表明:采用传统工艺生产的车轴钢内部存在1.0~1.2 mm的团聚型大尺寸Al_(2)O_(3)+2CaO夹杂物。通过提高转炉终点碳和磷一次命中率、转炉终点Al含量由0.015%~0.020%提高到0.020%~0.025%,Ca含量由0.0010%~0.0015%提高到0.0015%~0.0020%,延长LF和VD软吹时间、减少LF和VD过程的铝线和硅钙线喂入量、增大中间包容量、增高中间包下挡墙、结晶器水口优化为6孔旋流水口等可有效控制大颗粒夹杂物的生成和去除。

The morphologies of inclusions in railway vehicle axle steel were observed by metallographic microscope,scanning electron microscope and energy dispersive spectrometer, and its composition was analyzed. The optimized process scheme was put forward, and the removal effect of the inclusions by the optimized process was studied. The results show that there are 1.0-1.2 mm agglomerated large-sized Al_(2)O_(3)+2CaO inclusions in axle steel produced by traditional technology. By improving the primary hit rate of carbon and phosphorus at the end of converter, increasing the Al content at the end of converter from 0.015%-0.020% to 0.020%-0.025%, and increasing the Ca content from 0.0010%-0.0015% to 0.0015%-0.0020%, prolonginf the soft blowing time of LF and VD, reducing the feeding amount of aluminum wire and silicon calcium wire in LF and VD process, increasing the capacity of tundish, increasing the lower retaining wall of tundish, and optimizing the submerged entry nozzle to a six-hole swirling flow nozzle, it can effectively control the formation and removal of large-particle inclusions.