82B小方坯连铸提高拉速的工艺优化实践

TOPTIMIZATION AND PRACTICE OF BILLET CONTINUOUS CASTING PROCESS FOR IMPROVING CASTING SPEED OF 82B STEEL

为提高82B生产效率,在北营炼钢厂2号小方坯铸机上开展提高拉速的生产试验,特别针对铸坯芯部质量进行多工艺的综合优化,以实现高效高质生产。首先,建立该铸机的凝固传热数学模型,并结合比色测温方法对模型中待定参数进行修正;针对中心偏析和缩孔质量问题,结合修正后凝固传热模型和相应冶金准则对拉速、二次冷却、电磁搅拌等参数进行了优化计算;最后通过生产试验比较,确定工艺优化的方向和效果。最终优化确定拉速2.25 m/min,比水量为1.7 L/Kg,结晶器电磁搅拌参数为260 A/3Hz,末端电磁搅拌参数320 A/8Hz。工艺实践及分析表明,优化工艺后铸坯低倍中心碳偏析、缩孔均有较明显的改善。

In order to improve the production efficiency of 82B,production tests were carried out on the No.2 billet continuous casting machine at Beiying Steelmaking Plant to increase the casting speed,with a special focus on the comprehensive optimization of the quality of central part,to achieve both high-efficiency and high-quality.Firstly,a heat transfer and solidification model has been established for the continuous casting billets,and then the undetermined parameters in the model were calibrated using a colorimetric pyrometer.Secondly,in response to the issues of central segregation and shrinkage quality,optimization calculations were carried out on parameters such as casting speed,secondary cooling,and electromagnetic stirring by combining both the calibrated solidification heat transfer model and corresponding metallurgical criteria.Finally,by comparing production tests,the direction and effectiveness of process optimization are determined.The final optimization results indicates that it is proper with casting speed of 2.25 m/min,a specific water flow of 1.7 L/Kg,electromagnetic stirring parameters of 260 A/3Hz for the mold electromagnetic stirring,and 320 A/8Hz for the final electromagnetic stirring.Process practice and analysis both indicate that the optimization of the process has significantly improved the center carbon macro-segregation and shrinkage of the billet products.