低温变形Nb微合金钢铁素体相变的数学模型

以热力学和动力学理论为基础，研究了Nb微合金钢热变形过程中铁素体相的形核及长大过程，在形核速率计算中引入变形储能、晶界凸阶及微合金元素的作用，建立了低温变形诱导铁素体相变的动力学模型，分析了热变形参数和化学成分对相变分数和晶粒尺寸的影响．变形温度的降低和变形程度的增加，促进了α相变过程，相变体积分数增加，晶粒得到细化．C与Mn含量增加的效果则相反．模型应用于热轧带钢生产过程的模拟，计算结果和实测结果吻合良好．

Mathematical model of ferrite transformation of Nb microalloyed steels through low temperature heavy deformation

Based on the transformation thermodynamics and kinetics, the nucleation and growth of ferrite grain during hot deformation in Nb microalloyed steels were investigated. In view of the effect of deformation stored energy, effective deformation ledge and alloying composition, the basic kinetics model was established to simulate deformation induced transformation behavior, The transformation is promoted and more volume fraction and finer grain are obtained at high strain and low temperatures, whereas the reverse is true as C or Mn content increases, The present models can be applied to simulate the evolution of microstructure during hot--strip rolling. The results are in good agreement with measured ones.