【摘要】 利用金相显微镜、扫描电子显微镜、能谱仪和X-射线衍射分析等方法,研究高温运行165 000 h后X20Cr Mo V12.1钢焊缝金属的微观组织变化情况。结果表明:经长期高温运行后X20CRMOV12.1钢焊缝金属基体组织板条马氏体发生分解而碎化,位错密度降低;组织中的析出相主要由M23C6型碳化物和L aves相组成,其中M23C6在晶界析出并聚集长大,呈连续链球状或孤立颗粒状分布,在晶内主要呈细小颗粒状分布,组织中的L aves相尺寸较大呈孤立颗粒状分布。晶界上粗大的M23C6和大尺寸的Laves相与基体结合力较弱,易与基体剥离而导致焊缝金属性能降低。更多还原

【Abstract】 Microstructure variation of X20 Cr Mo V12.1 steel weld metal after long-term service is investigated by metalloscope,scanning electron microscope,energy disperse spectroscopy and X-ray diffraction analysis. The results show that matrix of X20 Cr Mo V12.1 steel weld metal after long-term service is still lath martensite,but the lath martensite is decomposed and fragmentized,and the dislocation density reduces. The precipitated phase mainly consists of M23C6 carbide and Laves phase. And M23C6 is precipitated along grain boundary and forms continuous hammer throw or isolated particle distribution,and small granular distribution in interior grain. The size of Laves phase is larger in isolated particle distribution. Bulky M23C6 on the grain boundary and big size Laves phase substrate are weak and matrix is easy to be stripped. This will reduce the weld metal performance.更多还原