钢铸态热膨胀特性研究

Study of Thermal Expansion Properties of as Cast Steels

利用现代高温热膨胀检测技术并结合热物性模型计算,获得了连铸过程含碳量在0.09%～0.75%之间常用8个钢种的线性热膨胀、瞬时线膨胀系数及其温度相关性。试验结果表明,连铸冷却条件下,钢的线性热膨胀和与之相关的瞬时线膨胀系数在奥氏体温区、固态相变温区和相变结束至室温等三个温区内受碳含量的影响程度不同。利用试验数据对瞬时线膨胀系数的模型计算进行了验证,并研究凝固过程以及热历程对钢的热膨胀特性的影响;分析了瞬时线膨胀系数与平均线膨胀系数的差异以及不同钢种间热膨胀的差异性。

The thermal linear expansions and the related thermal expansion coefficients of some commercial steels, with carbon content from 0.09% - 0.75%, at elevated temperatures were given through a thermal expansion test combined with thermo physical calculation. At the temperature range of austenite phase, solid phase transformation and below the eutectoJd reaction, tbe carbon content had different influence on the thermal linear expansions and their thermal linear expansion coefficient of steel. Based on the validation through experimentation of steels at solid state, a thermo-physical calculation model was presented for the determination of steel thermal expansion properties at solid liquid coexistent state. Accordingly. the effect of solidification and the related thermal history on the steel thermal expansion was revealed. The difference of the value of the real thermal expansion coefficient and the average thermal expansion coefficient, and the difference of thermal expansion among the given steel grades were analyzed.