基于Ｆｅ－Ｃ合金的微观组织结构，建立了碳钢线性热膨胀系数计算模型，计算出不同碳含量的钢种在不同温度下的瞬时线性热膨胀系数，并将计算值应用于铸坯热—弹—塑性应力模型，研究了包晶相变对连铸坯初生坯壳凝固收缩的影响。模拟结果表明：浇铸碳含量在０．１％附近的包晶钢时，初生坯壳在靠近弯月面区域和角部区域的收缩很不规则，容易诱发表面缺陷 Based on the microstructure of Fe-C alloy, a linear thermal expansion coefficient calculation model of carbon steel was set up to calculate the instantaneous linear thermal expansion coefficient of steel with different carbon content at different temperatures. The calculated values ​​were applied to the hot- Plastic stress model, the effect of peritectic phase transformation on solidification and shrinkage of primary billet of continuous casting billet was studied. The simulation results show that when the peritectic steel with the carbon content around 0.1% is cast, the shrinkage of the primary shell near the meniscus and the corner is very irregular, and the surface defects