Abstract: The inclusion detection methods such as sample electrolysis and ASPEX scanning electron microscope were used, the change law of type and size of nonmetallic inclusions in molten steel and cast slab of impact zone and pouring zone before and after using tundish channel filter has been studied. The results show that the submerged nozzle is not blocked after using the filter；the filter has good removal effect on inclusion particles larger than 30um. In terms of total number of inclusions ,the impact zone inclusions > billet inclusions ; the pouring zone inclusions,this is because the molten steel partial inclusions in pouring zone float up and absorb by the filter, and the Al₂0₃ number of unit area in the pouring zone is significantly reduced compared with the impact zone, indicating that the filter has best removal effect on Al₂0₃ series inclusions ； the size distribution of most inclusions is below 10um. After using the filter, the number of inclusions per unit area in the pouring zone is less than that in the impact zone by 23. 3%. Reasonable process parameters of tundish: molten steel flow rate 5.38 t/min,and distance between filter and long nozzle is 1200 mm.

Key words: Channel Filter, Inclusion, Impact Zone, Pouring Zone ,