论文部分内容阅读
在Thermo-Calc热力学软件的辅助设计下,制备了一种针对超临界水堆工况的12Cr低活性铁素体/马氏体钢。通过显微组织观察与分析,同时结合热力学及动力学计算,研究了含12%(vol%)δ铁素体的12Cr3W钢析出行为。结果表明:1050℃淬火780℃回火后,12Cr3W钢中析出相主要为M23C6和Cr2N。M23C6主要在回火马氏体内析出,而针状Cr2N则主要在δ铁素体内析出,Cr2N相对于M23C6容易发生粗化长大,计算结果与实验值吻合。12Cr钢淬火回火后的析出相组成受δ铁素体影响。借助于Thermo-Calc软件计算得到的热力学平衡相图选择合适的淬火温度,可以有效控制淬火后δ铁素体相含量,从而优化显微组织中析出相。
A 12Cr low activity ferritic / martensitic steel for supercritical water reactor operation was prepared with the aid of the Thermo-Calc thermodynamic software. Through the observation and analysis of the microstructure, the precipitation behavior of 12Cr3W steel with 12% (vol%) δ ferrite was studied based on the thermodynamic and kinetic calculations. The results show that the precipitated phases of 12Cr3W steel are mainly M23C6 and Cr2N after quenched at 1050 ℃ and tempering at 780 ℃. M23C6 mainly precipitated in tempered martensite, whereas acicular Cr2N precipitated mainly in δ-ferrite, and Cr2N tended to coarsen with respect to M23C6. The calculated results agree well with the experimental data. The composition of precipitated phase of 12Cr steel after quenching and tempering is influenced by δ ferrite. With the thermodynamic equilibrium phase diagram calculated by Thermo-Calc software, selecting proper quenching temperature can effectively control the δ-ferrite phase content after quenching so as to optimize the precipitated phase in the microstructure.