V-N微合金钢的析出行为预测分析

Prediction Analysis of Precipitation Behavior of V-N Microalloyed Steel

基于JMatPro热力学模拟软件对V-N及V-N-Cr微合金钢中平衡相析出行为进行研究,并与轧制过程获得的V-N-Cr微合金钢的析出行为进行了对比。结果表明:V-N钢与V-N-Cr微合金钢具有多种相同的析出第二相,包括MN、Al N、MnS、M(C,N)、M23C6、M6C析出相,M(C,N)和MN的析出强化作用较明显。Cr元素的添加能促进V(C,N)析出,阻碍VN析出。V-N-Cr微合金钢的TEM组织中多边形铁素体基体含有大量的高密度位错,V(C,N)析出相细小,弥散分布,包含两种尺寸类型,尺寸在10~20 nm的V(C,N)析出相,主要在第一阶段轧制及等温阶段形成。尺寸在3~5nm的析出相,在精轧阶段后期缓慢冷却过程中形成。这与JMatPro软件所计算预测出的M(C,N)高温析出阶段和低温析出阶段的结果基本相同。

The precipitation behavior of V-N and V-N-Cr microalloyed steels was studied by thermodynamic simulation calculation of JMatPro software, which were compared with that the precipation behavior of V-N-Cr micro-alloy steel in rolling. The results show that V-N and V-N-Cr microalloyed steels have many identical precipitates, including MN, Al N,MnS, M(C, N), M23 C6 and M6 C. The precipitation strengthening effect of M(C, N) and MN is obvious. The addition of Cr element can facilitate the precipitation of V(C, N), which impede the precipitation of VN. The polygonal ferrite matrix in the TEM of V-N-Cr microalloyed steel contains a lot of high density dislocation. V(C, N) precipitates out the fine dispersion distribution, including two types of sizes. The precipitation phase of V(C, N) between 10-20 nm is mainly formed in the first stage of rolling and isothermal stage. The precipitation phase between 3-5 nm appears during the slow cooling process in the later stage of fine rolling, which are basically the same with the results of the predicted high temperature precipitation phase of M(C, N) and the low temperature precipitation phase calculated by JmatPro software.