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基于ANSYS建立37Mn5钢φ200mm断面圆坯连铸过程中的凝固传热数学模型,并通过射钉试验及表面测温对模型的准确性进行了验证,模拟研究了拉速、过热度以及比水量对凝固终点、铸坯表面温度以及铸坯中心过热消散位置的影响,研究结果证明:比水量对铸坯表面回温影响最大,每增加0.1L·kg~(-1),铸坯表面回温增加10℃,而拉速对凝固终点及铸坯中心的过热消散的位置影响最大,拉速每增加0.1m·min~(-1),凝固终点及铸坯中心的过热消散的位置分别增加1.1m和0.8m,并从理论上验证了φ200 mm断面生产37Mn5拉速从1.4m·min~(-1)提高到1.8m·min~(-1)的可行性,另外考虑到37Mn5的高温热塑性特点及二冷冶金准则,针对铸坯存在的质量缺陷,优化二冷工艺制度,工业试验结果表明:低过热度(25℃以下),比水量为0.3L·kg~(-1),拉速从1.4m·min~(-1)提高到1.8m·min~(-1)时,铸坯低倍质量良好,无内裂纹以及中心缩孔,中心等轴晶率为35%,但过高的过热度(30℃以上)会存在中心缩孔。
Based on ANSYS, the mathematical model of solidification and heat transfer in continuous casting of round billet of φ200mm section of 37Mn5 steel was established. The accuracy of the model was verified by nailing test and surface temperature measurement. The effects of casting speed, superheat and specific water ratio The end of solidification, the surface temperature of the billet and the overheat dissipation position of the billet center. The results show that: the specific water has the greatest effect on the surface temperature of the billet, with the increase of 0.1L · kg ~ (-1) 10 ℃, while the pulling speed has the greatest influence on the position of the end of solidification and the overheat dissipation of slab center. When the pulling rate increases by 0.1m · min ~ (-1), the end of solidification and the overheating dissipation center of the slab increase by 1.1m And 0.8m, respectively, and theoretically verified the feasibility of increasing the pulling speed of 37Mn5 from 1.4m · min -1 to 1.8m · min -1 at φ200 mm cross section. In addition, taking into account the high temperature thermoplastic characteristics of 37Mn5 And secondary cooling metallurgy rules. According to the quality defects existing in the slab, the secondary cooling technology was optimized. The results of industrial tests showed that the specific heat rate (0.3L · kg ~ (-1)) and low superheat (25 ℃) When 1.4m · min ~ (-1) increased to 1.8m · min ~ (-1), the cast slab had good low quality, no internal cracks and shrinkage , Equiaxed grain was 35%, but the high degree of superheat (above 30 ℃) center shrinkage cavity exist.