Abstract: The addition of rare earth to steel can improve its cleanliness and properties. The research progress of rare earth treatment in Al-killed steel was reviewed. The development and current status of rare earth-containing steel was outlined firstly. Then the effects of adding rare earth to molten steel were summarized on steel cleanliness, inclusion modification, microstructure and mechanical properties, as well as corrosion and oxidation resistance. Among them, the influence of rare earth treatment on inclusions in steel was described in detail including their modification mechanism, evolution, size, density and distribution characteristics, etc. In addition, researches on slag bearing rare earth were introduced including its application in electroslag remelting as well as slag-steel reaction in secondary refining. Finally, a summary and suggestions were provided to offer references for future research and application of rare earth-treated steel.

Key words: Al-killed steel, rare earth treatment, inclusion, microstructure and properties, slag bearing rare earth