Chloride corrosion problem in heat exchangers
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There is currently a high-pressure heat exchanger with 2-pass U-tube threaded lock ring design. It has been found that chloride corrosion is severe at the inlet end of the tube side, resulting in stress cracking in multiple heat exchange tubes at a distance of 10 mm from the tube ends. However, on the other side of the partition, namely at the outlet end of the tube side, none of the heat exchange tubes have cracked. Dear experts, what could be the possible reasons for this?
The combined effect of stress corrosion and electrochemical corrosion. It is recommended to use polymer materials for repair and protection, which can achieve excellent results.
Stress corrosion is a definite issue; what about electrochemical corrosion? I hope you can give me some advice
Are the material of the tube and the material of the plate different? Based on your description, 10 mm from the pipe end – is that the location where the pipe end meets the tube sheet? Due to factors such as temperature and pressure, after stress corrosion-induced defects occur, the potential difference between different materials becomes more pronounced rapidly, leading to an increased corrosion rate. On the other side, there is also corrosion, but at a very slow pace.
Take a look at the post I shared in my topic; a typical case mentioned in \"An Overview of Abnormal Failures in Petrochemical and Nuclear Isostatic Equipment\" is the expansion joint corrosion issue in stainless steel heat exchanger tubes. It is the crimping stress at the crimping step that causes corrosion failure under the action of chloride ions……
Choosing the wrong materials in an attempt to save money ends up costing more in the long run; if chlorides are present, a thorough inspection is necessary: lol
Choosing the wrong materials in an attempt to save money ends up costing more in the long run; when chloride ions are present, it’s better to use ordinary materials to truly save money: lol