Abstract: Exploration and research on composition control of nitrogen in high strength IF steel in Shougang qiangang have been introduction in this paper. Production technology and the method of preventing the increasing of nitrogen in high strength IF steel have been summarized also. The production process of low nitrogen steel during converter smelting includes decreasing reblowing numbers and reblowing time, controlling the condition of combined blowing and modifying top slag which contains high nitrogen content. And the production process of low nitrogen steel during RH refining includes improving vacuum degree rapidly, increasing argon circle flow, melting cold steel in vacuum chamber and inert gas protection technology and preventing nitrogen increasing in submerged tube. The average nitrogen content in low nitrogen steel produced by Qiangang is about 15×10^-6 % by using the above technologies.

Key words: low-nitrogen steel, reblowing, submerged tube modification