型壳参数对定向凝固两相区温度梯度的影响

Effect of Mould Parameters on Interface Temperature Gradient during Directional Solidification Process

采用数值模拟与实验验证相结合的方法研究了型壳不同预热温度和厚度对凝固两相区温度梯度的影响。型壳预热温度对温度梯度的影响主要表现在凝固前期;型壳厚度对温度梯度的影响主要体现在凝固后期热量的散失方式上。结果表明,在型壳的预热温度从1 450℃增加到1 550℃的过程中,平均温度梯度不断增大,最大值为42.1℃/cm;分别考察了4~8 mm厚度型壳的凝固过程,平均温度梯度先增大后减小,当型壳厚度超过一定范围时,温度梯度的变化很小,在厚度为6 mm时达到最大值43.8℃/cm。

Effect of different preheating temperature and thickness of the shell mould on solid-liquid interface temperature gradient have been investigated based on numerical simulation associated with experimental verification.The effect of preheating temperature on solid-liquid interface temperature gradient mainly works during the earlier stage of solidification;effect of mould thickness on solid-liquid interface temperature gradient mainly embodies from the mode of heat losing.The results show that with the addition of the initial temperature of the shell mould from 1 450 ℃ to 1 550 ℃,the solid-liquid interface temperature gradient increases gradually,and reaches its maximum of 42.1 ℃/cm;we also investigate the solidification process with different shell mould thicknesses from 4 mm to 8 mm,the solid-liquid interface temperature gradient seems the largest when the thickness is 6 mm,which is 43.8 ℃/cm.