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在对双相钢两相区奥氏体化过程进行热力学与动力学分析的基础上,建立了两相区奥氏体化过程的扩散模型,并采用显式有限体积法对740℃与780℃下的奥氏体化过程进行了数值求解.模拟结果表明:奥氏体长大初期受C元素在奥氏体中的扩散控制并很快达到亚平衡.该阶段奥氏体长大速度较快.奥氏体长大后期受Mn元素在铁素体中的扩散控制.该过程由于Mn元素的扩散速率比C元素的扩散速率低几个数量级而持续数千秒.当Mn元素在两相中的扩散通量相等时,奥氏体停止长大,Mn元素继续从铁素体向奥氏体中转移以完成其在两相中的均化.
Based on the thermodynamic and kinetic analysis of the two-phase austenitization process of dual-phase steel, the diffusion model of the two-phase austenitization process was established. The explicit finite volume method The results show that austenite growth is controlled by diffusion of austenite in the initial stage and subside rapidly to sub-equilibrium, and austenite grows faster at this stage . The later growth of austenite is governed by the diffusion of Mn in ferrite, a process that lasts for thousands of seconds due to the Mn diffusion rate being several orders of magnitude lower than the diffusion rate of C. When Mn is in two phases When the diffusion flux is equal, the austenite ceases to grow and the Mn element continues to transfer from ferrite to austenite to complete its homogenization in both phases.