建立了包晶钢连铸初始凝固包品相变过程的数学模型,研究了温度波动对此凝固过程的影响,计算了不同冷却速率、含碳量和温度波动幅度下δ,γ和L3相界面位置以及体积分数的变化.结果表明,温度波动导致包晶相变过程中γ相枝晶间的重熔、δ/γ界面位置和三相体积分数的不稳定变化,造成坯壳的不均匀生长和应力集中.这些现象在碳含量为0.1%0.17%的亚包品钢中尤其严重.分析认为,温度波动可能是包晶钢连铸时容易出现裂纹、难连铸的一个重要原因.
A mathematical model was proposed to study the influence of temperature fluctuation on initial peritectic solidification process in continuous casting. The variations of interface positions and volume fractions of three different phases, δ,γand liquid phase, were calculated under different cooling rates, carbon contents and temperature fluctuation amplitudes. The results show that remelting between dendritic structures, unstable variations of interfaces between δ-γ and volume fractions of different phases happened when there was temperature fluctuation, which lead to uneven growth and stress concentration in the shell. These phenomena are especially serious in the hypo-peritectic steel casting processing. It is considered that the temperature fluctuation is one of the important reasons leading to strong crack sensitivity and difficult casting of the peritectic steels.