Study on Characteristics of As-cast Structure of High Strength Steels Microalloyed with Ti by Thin Slab Casting and Direct Rolling Process

The as-cast structure,chemical composition segregation,dendrite arm spacing and inclusions of the high strength steels microalloyed with Titanium were investigated.The results show that there is no difference between CSP slab and conventional cast slab for macrostructure.However,the macrostructure of slab is relatively finer.The dendrite arm spacing is lower than conventional cast slab too.Segregation for elements C,S,P is large and the others segregation are small in the CSP slab.The big inclusions are few in the CSP slab.The Al,Ti,Ca and S inclusions are main inclusion in the slab,and the Ti,Ca and S inclusions content are few because the element content are few.The size of Al inclusion is lower than 2.5 μm,and equality in the slab.The content of Al inclusion is about around 0.001 4%~0.002 2% and no obviously gathering in the slab.