高温服役50000 h后P92钢焊缝金属组织变化

Microstructure Evolution of P92 steel Weld Metal after Servicing at High Temperature for 50000 h

利用金相显微镜、扫描电子显微镜和X射线衍射分析等方法研究了服役50 000 h后P92钢焊缝金属的组织变化。结果表明,服役前P92钢焊缝金属析出相主要为细小颗粒状的M23C6,服役50 000 h后马氏体板条依然清晰,组织中析出相数量显著增多,除M23C6相外沿晶界和板条界分布了大量的块状Laves相,其数量和尺寸均大于M23C6相。这将对P92钢焊缝金属的性能产生不利影响。

Microstructure evolution of P92 steel weld metal after serving for 50 000 h was investigated by means of optical microscopy, electron microscopy, X-ray diifractometer and so on. The results show that the precipitates in the P92 steel weld metal are mainly fine granular 23C6 before service. After serving for 50 000 h, martensito lath in the weld metal remains clear. However, the amount of precipitates increases apparently. In addition to M23C6, a lot of block Laves phases are distributed along the grain boundary and lath boundary. The amount and size of Laves phases are bigger than those of 23C6 phase, which results in detrimental influence on the properties of the weld metal.