材料期刊网

高速铁路对重轨钢质量提出了更高的要求，洁净度与均质性控制是其质量提升的关键。包钢高速重轨钢采用无铝脱氧工艺降低钢水全氧质量分数、VD 真空脱气工艺强化脱氢、全程保护浇注与中间包冶金防止钢水二次氧化和促使钢中夹杂物上浮，提高钢的洁净度；通过合理控制钢液过热度、严格控制拉速、采用结晶器电磁搅拌、动态二冷、动态轻压下控制等关键技术来减轻和消除铸坯中心偏析，提高钢的均质性。生产实践表明，高速重轨钢中w T [O]≤0．0020％、w [N]≤0．0050％、w [H]≤0．00015％、w [Al]≤0．0040％，A 类夹杂物不超过2．0级，B、C、D 类夹杂物不超过1．0级，中心 疏 松 评 级 不 超 过1．0级 的 比 例 平 均 为 83．1％，中心缩孔不超过0．5级的比例平均为94．3％，中心碳偏析指数最大为1．07。包钢高速重轨钢综合质量满足了《时速200 km 客运专线铁路用钢轨标准》的要求。

High quality of heavy-haul rail steel is necessary for high-speed railway.Therefore,improving the cleanli-ness and homogeneity of high-speed heavy rail steel are the key technologies for improving the product quality. Technologies such as using the oxidizing technology of non-Aluminum,vacuum degassing (VD),protecting cast in all process and the tundish metallurgical technology,strict casting speed and molten steel temperature control,M-EMS,dynamic secondary cooling and dynamic soft reduction control technologies were used in Baotou Steel.The practice shows that in the high-speed heavy rail steel,w T [O]≤0.002 0%,w [N]≤0.005 0%,w [H]≤0.000 15%,w [Al]≤0.004 0%,non-metallic inclusions category A ≤2.0 level,while B ,C and D ≤1.0 level.The average rate of center looseness index≤1.0 is 83.1%,the average rate of center shrinkage cavity index≤0.5 is 94.3%,and the highest index of carbon central segregation is 1.07.The quality of the production can meet the requirements of “rail standards for the 200 km/h speed railway line for passenger transportation”.