Abstract: The hard points in 20CrMnTiH gear steel can cause difficulty in sawing, this kind of difficult sawing quality problem is more intuitive, and saw blade fatigue life is greatly reduced under the same cutting speed. Through the LF refining furnace submerged arc operation, reasonable bottom blowing argon stirring system, use high aluminum preslug system, implementation of such measures as tundish sealing, control the oxygen content and nitrogen mass fraction in 20CrMnTiH gear steel under 14×10-6 and 60×10-6 respectively, the hard-point defects in 20CrMnTiH gear steel can be effectively solved.

Key words: hard spots, submerged arc operation, secondary oxidation, TiN, Al2O3