300M钢奥氏体晶粒等温长大模型

Isothermal growth model of austenite grain for 300M steel

为研究300M钢奥氏体晶粒保温长大规律,在不同保温时间（5~120 min）和保温温度（900~1150℃）下开展了加热炉保温实验,并通过腐蚀法获得了不同条件下的晶粒尺寸。实验结果表明,晶粒尺寸随保温温度的升高和保温时间的延长而增大,但晶粒长大速率随保温时间的延长而减小。晶粒尺寸与保温时间整体上呈幂指数小于1的幂函数形式。同时,温度越低晶粒尺寸越快趋于稳定。保温温度在1000℃以上时,晶粒生长迅速。基于实验结果建立了晶粒尺寸与初始晶粒尺寸、保温时间、保温温度关系的复合模型,模型的平均相对误差为4.38%,最大相对误差为12.47%。与Sellars模型和Anelli模型相比,该模型具有更高的精度。

To investigate the austenite grain growth law of 300 M steel,the heat preservation experiments under different temperatures（ 900-1150 ℃） and time（ 5-120 min） were carried out and the grain size under various conditions was obtained by etching method.The results show that the grain size increases with increasing holding temperature and holding time,but the growing rate decreases with increasing holding time. The relationship between grain size and holding time basically follows the exponential function in which the power exponent is less than one. The grain size tends to be stable faster at lower temperatures. However,the grains grow rapidly when holding temperature is above 1000 ℃. The relationship between grain size and initial grain size,holding time and holding temperature was described using a combined model,and the mean relative error and maximum relative error were 4. 38% and 12. 47%,respectively,which showed that the combined model was more accurate than the Sellars model and the Anelli model.