摘要
利用光学显微镜、扫描电镜以及能谱仪对超超临界机组服役8 000h后的主蒸汽管道P92钢焊接接头焊缝金属中的微裂纹进行了观察,分析了微裂纹的形态、分布和性质。结果表明:P92钢焊接接头焊缝金属中的微裂纹呈蠕虫状断续分布,走向既有沿晶又有穿晶;在裂纹尖端区域有大量析出相;微裂纹的产生与应力和微区的组织状态有关,它起源于焊接过程中的低温区,是由微小脆化裂纹在应力场的作用下相互连接而形成的。
Some micro-cracks were found in weld metal of P92 steel welded joint in ultra supercritical unit after 8 000 h service, these micro-cracks were observed and analyzed by optical microscopy （OM）, scanning electron microscopy （SEM） and energy dispersive spectroscopy （EDS）. Morphology, distribution and property of these micro-cracks were analyzed. Results show that both intergranular and transgranular cracks in P92 steel welded joint were presented, and the micro-cracks showed wormy shape with discontinuous distribution. A large number of precipitates were distributed in the front area near the crack tips. The formation of micro-cracks was related with stress and structure of micro-zone, and the micro-cracks derived from low temperature region during welding procedure and formed from interconnection of micro brittle cracks under the influence of stress field.
出处
《机械工程材料》
CAS
CSCD
北大核心
2017年第2期45-50,共6页
Materials For Mechanical Engineering
