Aermet100钢高温保温过程奥氏体晶粒演化的原位实验研究

In-situ experimental investigation on austenite grain evolution in Aermet100 steel during high temperature holding process

材料在加热保温过程中的微观组织演化会影响后续的变形过程。为了实现材料热变形过程中微观组织的有效调控,采用高温激光共聚焦设备原位研究了Aermet100钢在加热保温过程中奥氏体晶粒的演化规律。结果表明:随着加热速度的减小、保温温度和保温时间的增加,奥氏体晶粒尺寸增加。相比于加热速度和保温时间,保温温度对奥氏体晶粒尺寸的影响更显著。1000℃为Aermet100钢奥氏体晶粒长大的临界温度,当保温温度低于1000℃时,奥氏体晶粒尺寸较小;当保温温度高于1000℃时,奥氏体晶粒尺寸显著增加。基于统计的晶粒尺寸,提出了两种耦合加热速度、保温温度以及保温时间影响奥氏体晶粒长大的模型,两种模型的预测值均与实验值吻合很好,表明建立的两种晶粒长大模型是可靠的。

The microstructure evolution of materials during the heating and holding process will affect the subsequent deformation process.Therefore,in order to realize the effective control of microstructure during the hot deformation process of material,the austenite grain evolution law of Aermet100 steel during the heating and holding process was studied in-situ by high temperature laser confocal equipment.The results show that the austenite grain size increases with the decreasing of heating rate and the increasing of holding temperature and the holding time.Compared with the heating rate and holding time,the holding temperature has a more significant effect on the austenite grain size.1000℃is the critical temperature for the austenite grain growth of Aermet100 steel.When the holding temperature is lower than 1000℃,the austenite grain size is smaller,and when the holding temperature is higher than 1000℃,the austenite grain size increases significantly.Based on the statistical grain size,two austenite grain growth models coupled with the effects of heating rate,holding temperature and holding time were proposed.The predicted values of the two models are in good agreement with the experimental values,which indicates that the two established grain growth models are reliable.