连铸工艺参数对38CrMoAl大圆坯碳偏析的影响  

Effects of continuous casting process parameters on carbon segregation degree of 38CrMoAl steel big round billet

作　　者：牛亮 仇圣桃[2] 赵俊学[1] 陈远清[2] 杨树峰[3] NIU Liang;QIU Sheng-tao;ZHAO Jun-xue;CHEN Yuan-qing;YANG Shu-feng(School of Metallurgical Engineering, Xi＇an University of Architecture and Technology, Xiran 710055, Shaanxi, China;National Engineering and Research Center of Continuous Casting Technology, Central Iron and Steel Research Institute, Beijing 100081, China;School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China)

机构地区：[1]西安建筑科技大学冶金工程学院,陕西西安710000 [2]钢铁研究总院连铸技术国家工程研究中心,北京100081 [3]北京科技大学冶金与生态工程学院,北京100083

出　　处：《钢铁研究学报》2018年第5期359-367,共9页Journal of Iron and Steel Research

基　　金：国家自然科学基金资助项目(51674185)

摘　　要：通过现场实验结合数值模拟的方法研究了连铸工艺参数（过热度、拉速、F-EMS）对直径为600mm的38CrMoAl连铸坯碳偏析的影响。研究结果表明,等轴晶比例和凝固组织质量都对碳偏析的严重程度有影响。过热度较低时,容易产生缩孔,而缩孔往往伴随着严重的偏析;过热度较高时,等轴晶比例更低,碳偏析同样严重,所以过热度控制在30℃更佳。拉速较大时利于柱状晶生长且凝固末端易产生中心缩孔,使偏析严重,因此拉速控制在0.19m/min时最佳。末端电磁搅拌有均匀钢液成分及温度,增加凝固末端组织致密度,减少中心缩孔,从而起到降低碳偏析的作用,但电磁搅拌效果受安装位置的影响较大。综合考虑工厂实际生产以及产量与质量之间的关系,合理的工艺参数是：过热度为30℃,拉速为0.28m/min,电搅组合方式为M-EMS＋S-EMS＋F-MES,电搅参数设置为M-EMS取101A/2Hz、S-EMS取200A/8Hz、F-ME取900A/8Hz。在上述工艺条件下F-EMS安装位置向弯月面方向移动0.4~0.5m会更为合理。The effects of continuous casting process parameters（superheat degree,casting speed and F-EMS）on the carbon segregation of round billet with diameter 600 mm of 38 CrMoAl steel were investigated by industrial experiments and numerical simulations.The results show that the equiaxed crystal rate and solidification structure both affect the carbon segregation.When the superheat is low,shrinkage tends to occur,and the shrinkage is often accompanied by severe segregation.When the superheat is high,the equiaxed grain ratio is lower,carbon segregation is also severer,so the superheat degree is controlled at 30℃.With the increasing of casting speed,it can obviously spur the growth of columnar crystals and formation of central pipe;both columnar crystals and central pipe are the major cause of segregation,so the suitable casting speed is 0.19 m/min.Final electromagnetic stirring has the effect of uniform liquid steel composition and temperature,which increases the density of solidification structure,and reduces the central shrinkage hole,thereby reducing carbon segregation,but the electromagnetic stirring effect is greatly affected by the installation position.Based on comprehensive consideration of the production and quality in practical production,the suitable process parameters are established：the optimal superheat is 30℃,casting speed is 0.28 m/min,the combination of electromagnetic stirring is M-EMS＋S-EMS＋F-EMS,and the corresponding electromagnetic stirring parameters are M-EMS of 101 A/2 Hz,S-EMS of 200 A/8 Hz,F-MEof 900 A/8 Hz.Under the above process conditions,it will be more reasonable for the F-EMS installation position to move 0.4-0.5 mtoward the meniscus.

关 键 词：38CrMoAl 连铸参数 碳偏析 数值模拟 大圆坯 

分 类 号：TF777[冶金工程—钢铁冶金]