建立了结晶器内连铸坯凝固过程的有限元数学模型．在坯壳表面边界条件中引入与气隙相关的传热模型修正平均热流量方程，研究了铸坯角部气隙对坯壳凝固行为的影响．模拟结果表明：铸坯角部形成的气隙显著地降低了坯壳表面的换热，使得铸坯偏角区成为热节区．此热节区是铸坯凹陷、裂纹等缺陷乃至漏钢事故发生的诱因． The finite element mathematical model of the solidification process of continuous casting slab in mold was established. The heat transfer model related to the air gap was introduced into the boundary conditions of the shell surface to modify the average heat flux equation and the influence of the air gap at the corner of the slab on the solidification behavior of the shell was investigated. The simulation results show that the air gap formed at the corner of the slab remarkably reduces the heat transfer on the surface of the shell, making the casting slant angle zone a hot zone. This hot zone is a slab depression, cracks and other defects and even the cause of the steel leakage accident.