Study On Carbon And Nitrogen Control During The Production Of IF Steel

In recent years, because the IF steel sheet has many excellent performances, such as deep drawing properties, high plastic strain ratio, high elongation, high-stiffness index, and lower yield ratio. It has gradually become a new generation of stamping steel after rimmed steel and aluminum killed steel. It is a sign of national automotive steel sheet production level . For common IF steel , the carbon and nitrogen content are below 0.003%, it can meet the quality requirements of steel sheets for common grade cars and trucks, but the steel sheets for high-end cars with high-quality , the carbon and nitrogen content need to control below 0.0025% .According to the trial plan decision and data analysis, this paper study the law of carbon and nitrogen content variation in the whole process of BOF, RH degasser and continuous casting. So analysis and appraisal has been done to control the carbon and nitrogen content, and the corresponding countermeasures and research direction are put forward.According to the IF steel trial practice research and data analysis of AnGang steel, carbon and nitrogen content are controlled mainly by final carbon and temperature control of BOF , vacuum pressure and treatment time of RH degasser, carbon content of the refractories that contact with liquid steel and casting protection by sealing , carbon and nitrogen are controlled at 19.9ppm and 18.4ppm approximately. The carbon increasing after RH decarburization can be lowered below 4ppm, and the nitrogen pickup after BOF can be lowed to below 5ppm.