【摘要】 为改善40CrA大方坯在现行工况连铸过程中产生的碳偏析问题，建立凝固传热数学模型和元胞自动机有限单元法(CAFE)模型，研究了拉速变化对大方坯凝固过程及组织的影响。结果表明，拉速为0.55 m/min时，CET(柱状晶组织向等轴晶转变)转变从距铸坯表面距离69 mm开始，到距铸坯表面122 mm处结束；拉速为0.59 m/min时，铸坯的柱状晶和等轴晶致密度最好。结合工业试验，结果表明，当其他工艺参数不变时，拉速由0.55 m/min提高到0.59 m/min时，碳偏析指数的极差由0.15减小到0.10,波动范围减小了33.3%,碳含量分布更加均匀，铸坯质量得到明显改善。更多还原

【Abstract】 The celluar automation finite element(CAFE) model and solidification heat transfer mathematical model were established to improve the problem of carbon segregation in the current continuous casting conditions of 40CrA bloom. And the influence of casting speed change on the solidification structure and microstructure of the bloom was studied. The simulation results show that, when the casting speed is 0.55 m/min, CET(columnar crystal structure to equiaaxial crystal transformation) starts from 69 mm away from the surface of the casting blank and ends at 122 mm away from the surface of the casting blank. When the casting speed is 0.59 m/min, the density of columnar crystal and equiaxed crystal is best. Combined with the industrial test, the results show that when the casting speed increases from 0.55 m/min to 0.59 m/min, the range of carbon segregation index decreases from 0.15 to 0.10, the fluctuation range decreases by 33.3%, the distribution of carbon content is more uniform, and the quality of billet is obviously improved.更多还原