中锰钢两相区退火奥氏体逆转变的数值分析

发布时间：2018-08-20 17:12

【摘要】：根据中锰钢热轧组织结构确立两相区奥氏体化的几何模型和初始条件,利用DICTRA动力学分析软件对中锰钢马氏体基体奥氏体化过程进行计算分析.在奥氏体化初期的形核过程中,马氏体中过饱和的碳锰元素从铁素体迅速转移到奥氏体并在相界面奥氏体一侧聚集.后续的相变过程中,碳在奥氏体中快速均化,但锰在相界面奥氏体一侧的聚集加剧.相变初期奥氏体界面推移速度比中后期高出若干个数量级,但随时间推移迅速衰减.相变初期相界面推移是碳扩散主导,相变后期界面推移受到锰在奥氏体中扩散速度制约.温度升高可显著提高相界面推移速度.达到相同数量奥氏体的情况下,低温长时退火有利于锰从铁素体向奥氏体转移并提高其在奥氏体中的富集度,从而提高奥氏体的稳定性.
[Abstract]:Based on the geometry model and initial conditions of two-phase austenitization, the austenitizing process of martensite matrix of medium manganese steel was calculated and analyzed by DICTRA software. During the nucleation of martensite in the early stage of austenitization, the supersaturated carbon-manganese element in martensite was rapidly transferred from ferrite to austenite and accumulated on the side of austenite at the phase interface. In the subsequent transformation, carbon was homogenized rapidly in austenite, but manganese accumulation on the austenite side of the phase interface was intensified. The interfacial velocity of austenite in the initial phase transformation is several orders of magnitude higher than that in the middle and late stage, but it decays rapidly with time. Carbon diffusion dominates the initial phase transition, and manganese diffusion velocity in austenite controls the interfacial evolution in the later phase transformation. The increase of temperature can significantly increase the velocity of phase interfacial movement. In the case of the same amount of austenite, the low temperature and long time annealing is beneficial to the transfer of manganese from ferrite to austenite and the enrichment of manganese in austenite, thus improving the stability of austenite.
【作者单位】：首钢技术研究院薄板研究所;北京科技大学材料科学与工程学院;
【分类号】：TG142.1;TG161

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