Study on Periodic Fluctuation of CC Slab Mould Level

摘要

Study on periodic fluctuation of mould level due to non-controlled factors is described in this paper,which includes that insufficient secondary cooling during continuous casting of low carbon steel causes bulging,uneven initial shell's thickness of peritectic steel makes bulging,and periodic shedding of the deoxidization products in the nozzle creates periodical fluctuation of steel flowing.According to the relevant data analysis of mould level periodic fluctuation for peritectic steel in a certain steel plant,it was found that the mould level fluctuation period was in precise direct proportion to the roller space,i.e.T=L/V(T is mould level fluctuation period,L is roller space for adjacent rollers,V is drawing speed of continuous caster),it was shown that main causes of mould level periodic fluctuation was casting blank bulging shell periodically extruded by segment section with equal roller space.Through changing roller space of certain segment sections,probability of mould level periodic fluctuation decreased to lower than original 50％,fluctuation scope reduced greatly.Results showed that the most effective method of resolving mould level fluctuation was to design segment sections with unequal roller space,self-compensating of mould level auto-controlling system for decreasing mould level fluctuation had some limits and its effect was unsteady,effect of adjusting cooling intensity (including powder and cooling water) was limited,which had no steady effect.