Abstract: Results of investigations on non-metallic inclusion control for high speed train axle steel and saw wire steel used for silicon wafer cutting are described in this article: (1) By means of further strengthening the RH vaccum refining, strictly control of the reoxidation and forming liquid inclusions which are not easy to aggregate to largesized inclusions, the number of the largesized inclusions in high speed train axle steel which contains 0.000 45 %－0.000 6 % T.O has been considerably reduced. (2) For the saw wire steel, by means of decreasing the amount of CaO-SiO₂-Al₂O₃ system inclusions, forming the MnO-SiO₂-Al₂O₃/SiO₂ dual-phase inclusions and strictly control of exogenous inclusions, the broken-resistance property of the steel wire in cold drawing fabrication has been remarkablly enhanced. (3) With the developed technologies, the wheel sets produced by Ma Steel Co. has been applied to the high speed trains on ShanghaiKunming line. The nonbroken length of the saw wires produced by Xingtai Iron and Steel Co. has been increased to more than 10 km, which has reached the world top saw steel product property level.

Key words: high grade special steels, high speed train axle, saw wire, non-metallic inclusion, refining, reoxidation