中文摘要：

以超期服役的F12马氏体耐热钢炉管作为研究对象,利用TEM、SEM、EDS等手段研究F12耐热钢组织结构在高温服役过程中发生的变化。通过研究材料的显微结构发现,服役过程中F12耐热钢中的马氏体组织发生明显的分解。晶界处的碳化物M23C6严重粗化,碳化物的化学成分变化明显,Cr含量的变化最为显著。而强化相MX相大量回溶,仅有少量残存于晶内。蠕变空洞形成于晶界粗化的碳化物处,和粗化的碳化物与基体出现明显脱离相关。

英文摘要：

The microstructure evolution of F12 heat resistance steel furnace tube with extended service at high temperature was studied by TEM,SEM and EDS methods.The results show that the disintegration of martensite is serious.The M23C6 on the grain boundary coarsens seriously and their chemical composition also changes significantly,especially for the content of Cr.Most of MX strengthening phase is redissolved during the service time,with only a little left within the grain.Creep void forms on the grain boundary,which is caused by separation of carbide from the matrix.