连铸增氮的影响因素与控制

Influential Factors and Control over Nitrogen Pickup in Continuous Casting

天钢连铸钢液的增氮较为严重,冶炼含铝钢时中包的氮含量基本在70 ppm以上,连铸增氮量在30 ppm左右,而国内先进水平的连铸增氮可以控制在3~5 ppm之间。通过实验分析发现连铸增氮的主要原因是大包套管的保护浇注不到位。对连铸氩封结构和气量进行调整,最终保证了连铸钢水氮含量可以控制在30~50 ppm。

The situation of nitrogen pickup in Tiangang casting was severe.The nitrogen content ofliquid steel in tundish in the melting of steel containing aluminum was over70ppm and continuousnitrogen pickup round30ppm while the same at advanced level domestically could be controlled within3~5ppm.Test and analysis found out that the main reason for continuous nitrogen pickup was impropersubmerged casting by ladle shroud.Adjustment was made on argon sealing structure and argon flow.Eventually the nitrogen content of liquid steel in casting could be controlled within30~50ppm.