Improvement on central porosity of large-sized round bloom by solidification end reduction during continuous casting  

作　　者：Peng Lan Liang Li Jia-quan Zhang 

机构地区：[1]School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing,100083,China

出　　处：《Journal of Iron and Steel Research International》2024年第12期2981-2996,共16页钢铁研究学报(英文版)

基　　金：This work is financially supported by the Fundamental Research Funds for the Central Universities(No.FRF-TP-19-017A3);National Natural Science Foundation of China(No.51874026).

摘　　要：A three-dimensional finite element model coupled with heat transfer,shrinkage accumulation and high temperature deformation was established forϕ690 mm round bloom in continuous casting,and it was verified by surface temperature,shell thickness,contour shape and porosity size by measurement.The compensation area of the shrinkage zone increases as the reduction amount increases.The compensation effect by the reduction of the unit with liquid core is about two times higher than others with fully solid matrix at a given reduction amount.A mathematical method to determine the reduction parameters for large-sized round bloom during continuous casting was proposed by the multi-rollers strategy.For theϕ690 mm round bloom,the suitable reduction parameters for Nos.2–6 units are suggested as 15,15,10,10,10 mm with a casting speed of 0.26 m min^(-1)to close the shrinkage with a diameter of about 17.5 mm in average.The industrial test on the reduction of large-sized round bloom for LZ50 steel was carried out.A total amount of 65–70 mm reduction was realized in the bloom for different casting speeds.The maximum diameter of the central porosity is about 16.3 mm in the longitudinal section at the casting speed of 0.24 m min^(-1),and it decreases to 7.3 mm after 65 mm reduction.Meanwhile,the maximum diameter of the central porosity is about 18.7 mm at 0.26 m min^(-1),while it decreases to 4.1 mm by a reduction of 70 mm.Finally,the difference of the solidification end reduction on round bloom and rectangular or square bloom is theoretically compared.Low deformation resistance and high bulge effect were found in round bloom compared to rectangular bloom.According to the results about solidification contraction accumulation and reduction efficiency in round bloom,the suitable reduction zone to control the central porosity during continuous casting is suggested to be 0.5–1.0.

关 键 词：Solidification end reduction Round bloom Simulation POROSITY Industrial test 

分 类 号：TF777[冶金工程—钢铁冶金]