Economizer tube leakage occurs after 34 days of use

and the leakage point is at the butt weld of the steel tube. In order to find out the leakage reasons

the base material composition test

microstructure observation and hardness test of the weld section are carried out

and the test results are compared with the specified requirements in the standard <GB 5310-2008 seamless steel tubes and pipes for high pressure boiler>

the material composition and hardness test results meet the requirements of relative standards. By observing the microstructure

it is found that the pores and internal cracks in weld fusion zone cause the decrease of the weld strength.In use process

the extension of internal cracks in work environment is the main reason for steel tube leakage at weld.