碳含量对奥氏体等温相变影响的数值模拟

Numerical Simulation of Effects of Carbon Content on Austenite Isothermal Transformation

利用二维元胞自动机介观模型对不同碳含量影响下钢的奥氏体-铁素体等温相变过程进行了数值模拟。模拟结果显示,等温相变最终铁素体体积分数取决于相变初期铁素体生长速度。由于碳含量不同,15SiMn钢铁素体初始生长速度较25SiMn钢的快,因而,最终铁素体体积分数较大。此外,模拟结果也显示,铁素体相的长大速度取决于奥氏体-铁素体相界处奥氏体相一侧碳原子浓度。15SiMn钢奥氏体相的平衡碳浓度较25SiMn钢的低。

The isothermal transformation of the steel with different carbon content during the process from austenite to ferrite transformation was simulated using two dimensions mesoscale cellular automaton model, The simulation results show that the final ferrite fraction depends on the average growth rate of ferrite grain at the initial stage of the transformation. Due to different carbon content, the average growth rate of 15SiMn steel is faster than that of 25SiMn steel, which results in bigger ferrite fraction in 15SiMn steel. In addition, the simulations also demonstrate that the average growth rate of ferrite grain is determined by the carbon concentration in austenite at austenite-ferrite interface. The simulated equilibrium carbon concentration in austenite of 15 SiMn steel is lower than that of 25 SiMn steel.