锅炉水冷壁横向裂纹开裂原因分析

Analysis of transverse crack and high temperature corrosion of boiler water cooled wall

某电厂锅炉的15CrMo材质水冷管管壁爆裂,发现为管道横向裂纹所致。采用宏观观察、扫描电镜及能谱分析、红外探伤研究裂纹产生原因,结果表明:裂纹在焊接热影响区粗晶部位萌生,表现为再热裂纹,内部残余应力和压应力导致裂纹进一步扩展,同时向火面有较厚的氧化层,基体组织严重球化,导致力学性能降低,在高温烟气环境下腐蚀开裂加速了管壁爆裂的发生。

Based on the cracking of 15CrMo steel water-cooled pipe wall of the boiler in a power plant,the transverse crack in the pipe is analyzed.By macroscopic observation,scanning electron microscope,energy spectrum analysis and infrared flaw detection,the results indicate that the cracks in the coarse grain part of welding heat affected zone are reheating cracks,the residual stress and compressive stress in the interior cause the cracks to expand further,at the same time,there is a thick oxide layer to the fire surface,and the matrix structure is seriously spherical,which reduce the mechanical properties.Corrosion cracking accelerates the occurrence of pipe wall bursting in high temperature flue gas environment.