热变形过程中γ→α相变开始温度的预测——C-Mn钢与Nb-v微合金钢

Predicting the Onset of Austenite-Ferrite Transformation During Hot Deformation of Low Carbon and Nb-V Microalloyed Steels

以Cahn理论和Scheil法则为基础,讨论了热变形过程对γ α相变的影响,预测了C Mn钢变形过程铁素体析出的开始温度Ar3d和Nb V钢连续冷却转变开始温度Ar3·结果表明,同样变形条件下,碳含量或锰含量越低的钢种Ar3d越高;同一成分钢种,随着变形量增大或变形速率降低Ar3d提高;随着冷却速率的增加,Ar3温度降低;变形可以提高Ar3温度·用该方法进行的计算机模拟结果和实验结果吻合良好,表明这种理论处理方法可用来模拟这种相变过程·

The influence of hot deformation process on austenite-ferrite transformation was investigated to predict the starting temperature of ferrite precipitation of low carbon steels during deformation (A_(r3d)) and the starting transition temperature of Nb-V microalloyed steels during continuous cooling (A_(r3)). The results indicate that the lower the C or Mn content, the higher the A_(r3d) temperature under the same deformation conditions, and A_(r3d) increases with increasing strain amount or decreasing strain rate for the same steel grade. On the other hand, A_(r3) decreases with increasing cooling rate and increases due to deformation. The simulated results were found in agreement with experimental ones, which implied that such a theoretical approach can be used to model the transformation process above mentioned.