Analysis of corrosion causes of low-pressure pipeline in a gas-steam combined cycle waste heat boiler

The rising pipe of the low-pressure evaporator of the waste heat boiler of a gas-steam combined cycle unit was "bursting" due to corrosion. The leaked elbow was intercepted on site, and the composition, microstructure, and corrosion product characteristics were analyzed using macroscopic morphology observation, SEM-EDS, etc. The reasons for corrosion were analyzed and discussed based on comprehensive information on the service environment and material characteristics. The results show that the corrosion of the inner wall of the elbow is erosion-corrosion and flowaccelerated corrosion of the mixture of water and water, and the corrosion of the outer wall is stress corrosion and oxygen corrosion.