Research on Dynamic Soft Reduction Technologies for Bloom Continuous Casting of Heavy Rail

With the aim of reducing the center looseness and central segregation of heavy rail steel bloom by en- hancing the metallurgical results of soft reduction(SR)employed in continuous bloom caster,a series of experi- ments for optimizing the process parameters of soft reduction is carried out.The influence of the soft reduction parameters on the internal quality of heavy rail steel bloom is analyzed,which include center looseness and cen- tral segregation etc.On the basis,the dynamic soft reduction scheme most suitable for heavy rail steel is devel- oped,which improves the internal quality of heavy rail steel bloom obviously.The practical operation shows that the ratio of center looseness≤1.0 is increased from 28% to 99.91%,central segregation and central shrinkage cavity are all≤1.0 whose ratio are 40.91% and 92.05% respectively before optimization,and central segrega- tion index of carbon is decreased from 1.17 to 1.05.Internal quality and mechanical performance of the rails produced from continuously cast blooms have met the requirement of 350 km/h high-speed tracks.