电站锅炉用TP304H不锈钢管显微组织的老化特征

应用金相、扫描电镜、透射电镜和X射线衍射等分析技术，研究了电站锅炉用TP304H不锈钢管显微组织老化的主要特征，明确了σ析出相含量与管子寿命的定量关系。结果表明：一定的压力条件下，TP304H钢管的显微组织变化与运行温度和时间相关，在设计温度下，随着运行时间的延长，TP304H钢管晶界开始析出呈链状分布的碳化物，继续运行σ相开始沿晶界（特别是三角晶界处）析出；当口相含量达到15％时，爆管几乎不可避免，因此，可以采用定量分析方法通过测定σ相含量来监测TP304H钢管的寿命。

Microstructure Degradation Characteristics of TP304H Stainless Steel Tubes Used in Power Plant Boilers

The microstructure degradation characteristics of TP304H stainless steel tubes used in power plant boilers were studied by means of optical microscope, scanning electron microscope, transmission electron microscope and X-ray diffractometer, and the relationships between the o-phase content and the life of the tubes were also given. The results show that under constant pressure, the microstructure transformation of TP304H tubes correlated with operating temperature and time, and as the operating time lasting, chain-like carbides would precipitate along grain boundaries at the design temperature and σ-phase would also precipitate along grain boundaries, especially in triangle ones. Tube bursting must happen if the total σ-phase content reached 15%, so quantitative method can be used to supervise the life of TP304H tubes by measuring the o-phase contenfi