Effect of relative process parameters of an 85 t VOD refining unit on end nitrogen content in ultra-pure ferrite stainless steel 00Crl8Mo2 and 00Crl7Mo is analyzed. Results show that with increasing initial carbon content

decreasing initial nitrogen content

increasing temperature of liquid steel and properly increasing denitriding time

the end nitrogen in liquid steel decreases； and with controlling initial carbon content in liquid steel- 0. 4% ~0. 9%

treading temperature ≥ 1590 °C

vacuum ≤70 Pa

denitriding time 15 〜20 min

blowing argon rate for stirring 8 ~ 15 L/(min • t) and initial nitrogen content in liquid steel ≤0.017 0%

the end nitrogen content in liquid steel is 0. 006 4% ~ 0.009 5% .