摘要
基于建立的连铸中间包及结晶器内钢液混合过程的物理模型,开发了板坯连铸异钢种连浇过程混浇坯长度及成分变化模型.以某钢厂单流板坯连铸机220 mm×1560 mm断面Q235与Q335Ti钢的混浇过程为研究对象,采用水模型试验结合数值模拟确定模型的关键参数,并通过开展现场试验对混浇坯取样验证模型的准确性.结果证明:混浇坯成分取样与模型预测的成分偏差小于5%,且模型预测的混浇坯长度与人工确定的一致.故采用该模型可跟踪不同混浇工况下中间包内及铸流上钢液的混合行为,准确预测混浇坯的长度以及成分变化规律.采用该模型研究了拉速及中间包内剩余钢液质量对混交坯长度及不同浇注长度铸坯C元素质量分数变化的影响规律.发现当拉速保持不变时,中间包内剩余钢液越多,混浇坯越长;当中间包内剩余钢液质量保持不变时,拉速越大混浇坯越短.相比而言,中间包内剩余钢液质量比拉速对混浇坯长度的影响更大.另外当拉速不变时,随着中间包内剩余钢液质量的增加,C元素质量分数由0.16%变化到0.18%的速率减慢;当中间包内剩余钢液质量不变时,随着拉速的增加,C元素质量分数由0.16%变化到0.18%的速率增加.因此异钢种连浇过程,适当提高拉速以及减少中间包内剩余钢液质量,可有效减少混浇坯长度,成分变化速率降低.
Based on a developed physical model during the mixing process in the tundish and the liquid pool of the strand,intermixed length and composition variation model have been established during steel grade changes in the continuous slab casting processes.The research object was the mixing process in the single-strand slab caster during steel grade changes of Q235 and Q335Ti steel with 220 mm×1560 mm section.Key parameters of the model were determined using the water model test and numerical simulation,and the model was verified through plant tests,which were performed on the slab caster during the grade transition period of continuous casting.Real grade intermixed slabs were produced,and composition distributions were measured and compared.The carbon composition and the length of the intermixed slab predicted using the model were found to be in good agreement with the experimental data.Mixed behaviors in the tundish and strand were tracked using the model under various mixing conditions.In addition,the length and the composition change law of the intermixed slab can be precisely predicted.The effect of casting speed and the remaining molten steel in the tundish on length and the composition change law of the intermixed slab were studied by the model.As the casting speed remains unchanged,the intermixed-slab length increases with more remaining molten steel in the tundish.While the mass of remaining molten steel in the tundish keeps unchanged,the intermixed slab length decreases with more casting speed.In comparison,the remaining molten steel in the tundish has a larger effect on the intermixed slab length than the casting speed.As the mass of the remaining molten steel in the tundish increases with constant casting speed,the rate at which the mass fraction of C changes from 0.16%to 0.18%slows down;While the mass of remaining molten steel in the tundish keeps unchanged,the rate at which the mass fraction of C changes from 0.16%to 0.18%accelerates with an increase in the casting speed.Reducing the mass of the residual molten steel in the tundish and increasing the casting speed in the strand is beneficial for the reduction in the length of the intermixed slab and element composition variation rate.Moreover,the strategy of lowering the liquid level in the tundish and increasing the casting speed simultaneously can be adopted to decrease the intermixed slab length to the greatest extent.
作者
安航航
焦树强
孙彦辉
刘崇林
宋思程
AN Hang-hang;JIAO Shu-qiang;SUN Yan-hui;LIU Chong-lin;SONG Si-cheng(Collaborative Innovation Center of Steel Technology,University of Science and Technology Beijing,Beijing 100083,China;State Key Laboratory of Advanced Metallurgy,University of Science and Technology Beijing,Beijing 100083,China;Guangxi Liuzhou Iron and Steel(Group)Company,Liuzhou 545002,China)
出处
《工程科学学报》
EI
CSCD
北大核心
2021年第12期1656-1665,共10页
Chinese Journal of Engineering
关键词
异钢种连浇
混浇模型
板坯连铸
混浇坯长度
成分变化规律
grade transition process
mixing prediction model
slab continuous casting
length of intermixed slab
composition change law