The main corrosion parts of heat exchanger are heat exchange tube, the joint between tube and tubesheet, the joint between tube and baffle, shell and so on. The corrosion causes are as follows:

1. Corrosion of heat exchange tubes

Because of the dirt and scale in the medium and the eddy current abrasion of the inlet medium, the pipeline is easy to corrode, especially at the pipe end of the 40~50mm inlet end of the pipeline, which is mainly related to the eddy current disturbance caused by the fluid at the dead corner.

Second, the corrosion of the joint between the pipe and the tubesheet and baffle.

There is stress concentration at the joint between the heat exchange tube and the tubesheet, and at the joint between the tube and the baffle, which is easy to produce cracks at the expansion joint. When there is a gap between the tube and the tubesheet, it is easy to cause the accumulation of Cl+ and the enrichment of oxygen, so it is easy to form pits or crevice corrosion on the surface of the heat exchange tube, which will become the crack source of SCC. The fracture of the joint between the pipeline and the baffle is often due to the long pipeline, many baffles and slight bending of the pipeline, which is easy to cause local stress concentration between the pipe wall and the baffle and the existence of cracks, so the joint becomes the weak link of stress corrosion.