非稳态浇注压下区间变化规律的研究与应用

摘要

To reduce center segregation and center porosity and improve internal quality of casting slabs based on adopting dynamic soft reduction,according to the measured data of the slab surface temperature during the actual production process of transient casting,a solidification heat transfer model was corrected.The variation rule of the effect of casting speed,superheat degree,and specific water flow on reduction position was analysed.The results show that for every 0.1 m/min increases in casting speed,the reduction length of AH36 and Q235B increases 0.15m and 0.21m respectively,and for every 10℃ increases in superheat degree,the reduction length of AH36 and Q235B increases 0.01m and 0.015m respectively,and for every 0.1L/kg increases in specific water flow,the reduction length of AH36 and Q235B increases 0.04m and 0.06m respectively.After the solidification heat transfer model was applied to production,the center segregation reduces to 1.0B~0.5C,and the cen-ter porosity less than level 1.5 increases from 35.25% to 85.16%,and the slabs internal quality is im-proved obviously.%为保证连铸板坯动态轻压下技术的有效实施以减轻中心偏析和中心疏松,改善铸坯内部质量,针对实际生产时的非稳态浇注过程,根据铸坯表面温度的测量数据,修正了实时凝固传热模型,分析了拉速、过热度和二冷比水量等工艺参数的变化对不同钢种压下区间长度的影响规律。结果表明：拉速每增加0.1m/min,船板钢AH36和碳素结构钢 Q235B的压下区间长度分别增加0.15m、0.21m；过热度每增加10℃,AH36和 Q235B 的压下区间长度分别增加0.01m、0.015m；二冷比水量每增加0.1 L/kg,AH36和 Q235B的压下区间长度分别减少0.04m、0.06m。将凝固传热模型应用于生产中,优化了动态轻压下模型,铸坯中心偏析减为1.0B~0.5C,中心疏松级别小于1.5级的铸坯比率由35.25%上升到85.16%,铸坯内部质量得到了明显改善。