冷轧双相钢连续退火加热与均热过程奥氏体化数值分析

Numerical analysis on austenitization of cold-rolled dual phase steel during continuous annealing heating and soaking stage

基于工业生产连续退火工艺,采用某双相钢700℃平衡态的热力学参数为两相区初始状态,对连续加热与均热过程的奥氏体化过程进行了数值分析。结果表明,计算的奥氏体转变动力学曲线与实测值吻合良好。连续退火奥氏体的形成是温度主导而非时间主导的过程。均热结束时C在奥氏体中分布较均匀。Si由奥氏体向铁素体扩散而在相界面铁素体一侧富集且难以均化,然而Mn和Cr由铁素体向奥氏体扩散而在相界面奥氏体一侧富集。短时连续退火过程中,奥氏体相界面的推移是C在奥氏体中扩散控制的过程。

According to the continuous annealing process of industrial production for a dual-phase steel,and using the equilibrium thermodynamic parameters at 700℃ as initial condition of intercritical annealing,the austenitization during continuous heating and soaking was analyzed by numerical method.The results show that the calculated austenitization dynamics curves are in good agreement with measured values.The formation of austenite in continuous annealing is dominant by temperature but not the time.C element distribution in austenite is homogeneous at the end of soaking.Si diffuses from austenite to ferrite and accumulates at ferrite side of the phase interface,whereas Mn and Cr diffuse from ferrite to austenite and accumulate at austenite side of the phase interface.In the short continuous annealing process,the move of austenite interface is a diffusion-controlled process of C in the austenite.