Abstract: Based on the statistical production data，indicating a relatively high nitrogen content of bearing steel GCr15 produced by 90 t EAF-converter, the main effects on the nitrogen content of molten steel at such stages as tapping, LF refining and VD treatment of steelmaking were analyzed, and the optimized process parameters were proposed to control the nitrogen content. Taking the advantage of the measures for nitrogencontrolling, the average nitrogen content before LF refining decreased by 7.2×10-6, the nitrogen pickup during LF refining reduced by 32.2 %, while the nitrogen desorption rate of VD furnace increased from 20.2 % to 29.2 %, and the nitrogen content of molten steel in tundish could be decreased from 49.7×10-6 to 35.7×10-6.

Key words: EAF-converter, GCr15 bearing steel, nitrogen content