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.