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针对Φ200 mm 37Mn5钢圆坯高拉速下铸坯存在的内部裂纹、中心缩孔与中心疏松等缺陷,结合生产实际分析得出过热度高、结晶器电磁搅拌强度偏小、二冷工艺及喷嘴布置不合适是引起铸坯质量问题的主要原因。通过建立经射钉及测温试验验证的凝固传热模型与采用高斯计测量电磁搅拌磁场的分布特征分别对二冷工艺制度和结晶器电磁搅拌参数进行优化,同时对二冷区喷嘴布置进行改进。结果表明:对于Φ200 mm断面37Mn5钢连铸拉速从1.4 m/min提高到1.8 m/min,铸坯内部质量明显改善,内部裂纹消失,中心缩孔和中心疏松均为0.5级,若过热度大于30℃,仍存在比较严重的中心缩孔。
Aiming at the defects such as internal cracks, shrinkage of center shrinkage cavity and center loosening of Φ200 mm 37Mn5 steel round billet, according to the actual production analysis, the superheat degree is high, the intensity of mold electromagnetic stirring is small, the secondary cooling technology and nozzle Improper layout is the main reason for the slab quality problems. Through establishing the solidification heat transfer model verified by the experiment of nailing and temperature measurement and the distribution characteristics of electromagnetic stirring magnetic field by Gauss meter, the second cooling technology and the electromagnetic stirring parameters of the mold were optimized respectively, and the nozzle arrangement in the second cooling zone was improved . The results show that the internal quality of the billet is obviously improved, the internal cracks disappear, the center shrinkage cavity and center looseness are both 0.5 for the continuous casting of Φ200 mm section 37Mn5 from 1.4 m / min to 1.8 m / min. If the superheat Greater than 30 ℃, there are still more serious center shrinkage.