转炉冶炼ER70S-6钢种氮含量控制实践

Practices on Controlling Nitrogen Content in Converter Smelting of ER70S-6 Steel

针对ER70S-6焊丝钢中氮含量高严重影响焊丝的拉拔速度,易出现断丝现象,不能满足用户需求,为了降低钢中的氮含量,对转炉炼钢工艺过程进行了系统的研究,探讨影响钢中氮含量的因素和控制措施。文章通过热力学分析氮在钢中的溶解机理,通过动力学分析研究了氮脱除的限制性环节,基于热力学和动力学分析,研究了炼钢工艺过程中入炉铁水硫含量、转炉顶渣料、转炉点吹次数、转炉出钢口维护对氮含量的影响及相应控氮措施。

The drawing speed of welding wire is seriously affected and fracture of welding wire is easy to happen due to high nitrogen content of the ER70S-6 welding wire steel so that user requirements cannot be met.In order to reduce the nitrogen content in steel,the technological process of converter steelmaking is studied systematically as well as the factors influencing nitrogen content in steel and control measures are discussed.In the paper,the dissolution mechanisms of nitrogen in steel are analyzed by thermodynamics,restricted links of nitrogen removal are analyzed and studied by dynamics as well as the influences of sulfur content in molten iron in furnace,slag charge in top of converter,times of spot blowing for converter and maintenance of tap hole of converter on nitrogen content and corresponding measures for controlling nitrogen content in the technological process of steelmaking are studied based on the thermodynamic analysis and dynamic mechanical analysis.