Abstract: In steels 16Mn and X60 with low S content (0. 003～0. 005%), rare earth metals (REM) still show ef- fects on purifying the molten steel and controlling the sulphide morphology. The optimum ratio of RE/S is about 2. 0, which causes lower content of oxygen and inclusions and higher impact toughness. The amount of REM in solid solution in the steel was determined by means of inductive coupling plasma (ICP) spectroscopy. The dissolved REM in low S steel could decrease the propor- tion of pearlite and increase the strength of the steel.

Key words: rare earths, low S steel, effect of REM