Abstract: Using bubbles to remove inclusions in steel is now becoming one of the important means of refining. The mechanism on inclusion removal by bubbles shows that inclusion floating through adhering by bubbles and involving in bubble wake are two main means of inclusion removal by bubbles. It has become a consensus that tiny bubbles have excellent effect on inclusion removal. In the present study, different inclusion removal methods by using bubbles and their prospect have been analyzed and compared, such as the argon blowing, argon injecting into shroud, fine and uniform heterophases in the molten steel, air curtain in the tundish, pressure elevating and reducing method, ultrasonic cavitation method, nitrogen absorbing and releasing method, inclusions removal by fine hydrogen bubbles method etc. The results show that tiny bubbles generated in steel on inclusions removal have better effect than the big bubbles. Nowadays, using dispersion tiny bubbles to remove inclusions in steel is paid more attention by the metallurgists. Some of the new inclusion removal technologies have been developed and are tending to be matured.

Key words: clean steel, bubble, inclusion, inclusion removal, fine hydrogen bubble method