Abstract: According the issue of nitrogen content in key steel grades being on the high side at Pangang, by survey and study it is defined that the main factors led to nitrogen being on the high side are the LD end nitrogen content in liquid being on the high side, serious pick-up of nitrogen during tapping and serious pick-up of nitrogen in the process from end refining to tundish, and the key technique to control o£ nitrogen in liquid is put forward including "LD low nitrogen blowing" ,"two-step deoxidation to control pick-up of nitrogen in tapping process" and "double argon sealing long nozzle shielding casting" etc. technique, it shall be to control the average LD end nitrogen in liquid no more than 13 x 10^-6, and the average pick-up of nitrogen in liquid during tapping and end refining process to tundish no more than 5 x 10^-6. Application results show the nitrogen content in finished products of beam steel slab, electrical steel and IF steel is respectively 30.3 x 10^-6 , 18.2 x 10^-6 and 16.3 x 10^-6 , and the average nitrogen content in finished products of heavy rail steel and tire cord steel is respectively 40. 8 x 10-6 and 38.2 x 10^-6 to greatly improve the control level of nitrogen content in low-ni- trogen steel grades at Pangang.

Key words: 120t LD-LF-RH-CC Flowsheet, Control of Nitrogen Content in Steel, LD Endpoint, Pick-up of Nitrogen, Long Nozzle

摘要： 针对攀钢重点品种钢氮含量偏高的问题,通过调研,确定了转炉终点钢水氮含量高、出钢过程增氮严重、精炼结束至中间包增氮严重是导致氮含量偏高的主要原因,提出“转炉低氮钢冶炼”、“两步脱氧控制出钢过程增氮”、“双氩封长水口保护浇注”等氮含量控制的关键技术,可将转炉终点钢水氮含量平均控制在13×10^-6以内,出钢过程及精炼结束至中间包增氮控制在5×10^-6以内。应用结果表明,板坯大梁钢、电工钢、IF钢成品氮含量分别为30.3×10^-6、18.2×10^-6、16.3×10^-6,方坯重轨钢和帘线钢成品氮含量平均为40.8×10^-6、38.2×10^-6,使攀钢低氮品种钢氮含量控制水平得到了大幅度的提升。

关键词: 120t LD-LF-RH-CC流程, 氮含量控制, 转炉终点, 增氮, 长水口