Analysis of the causes of flaking corrosion in 2205 duplex steel tube bundles

2205 duplex stainless steel possesses good corrosion resistance, but its corrosion resistance is severely affected in environments containing HCl (hydrogen chloride). Such an environment accelerates the degradation of the passivation film, thereby promoting the corrosion process. The bark-like \"rust layer\" that appears on the surface of duplex steel 2205 may be caused by the following factors: 1. **Effect of chloride ions**: Chloride ions in an HCl environment can penetrate the passivation film and react directly with the metal, leading to localized corrosion. The resulting corrosion products are large in size and loose, which in turn forms a rust layer that can be peeled off. 2. **Passivation film damage**: A passivation film typically forms on the surface of duplex steel 2205 to protect the metal from corrosion. However, in the presence of strong acids (such as HCl), this passivation film can be damaged, exposing the underlying metal and accelerating the corrosion process. 3. **Stress corrosion cracking**: In the presence of chloride ions, stress corrosion cracking (SCC) may occur in 2205 steel when stress is also present, leading to more severe corrosion. 4. **Effect of temperature and pH**: The temperature and pH of the environment in which it is used also affect the corrosion resistance of 2205 steel. An increase in temperature and a decrease in pH value usually accelerate the corrosion process. To address this issue, it is recommended to check and adjust the pH value of the operating environment, and to avoid direct contact between strong acidic media and metal surfaces as much as possible. At the same time, check for any external or internal stresses, and carry out stress relief treatment if necessary. Consider switching to materials more suitable for such corrosive environments or applying anti-corrosion coatings to the existing tube bundles. .

This post was last edited by CHANGBAISHI on 2024-8-10 09:56, who believed that corrosion was undoubtedly present. It is advisable to consider using other types of materials. Consider contacting the equipment manufacturers and design firms for advice, so as to get recommendations for suitable equipment for reference.

Although duplex stainless steel exhibits good corrosion resistance in many environments, its corrosion resistance may be compromised in reducing environments with high chloride concentrations, medium-concentration sulfuric acid or hydrochloric acid solutions at high temperatures, process environments containing halogenated hydrocarbons, and certain temperature and chloride environment conditions. As can be seen from the image, if there is a large amount of dirt and other deposits in its process medium, it accelerates the corrosion of the metal surface.

Yes. The ionic liquid alkylation unit will have tert-butyl chloride injected in the preceding process. The entire medium environment is a hydrochloric acid corrosion environment. All nickel-based alloys are susceptible to corrosion

Thank you for sharing; thanks for your selfless dedication. Is there any good method for stabilizing salts through internal heating in regenerated amine solutions? https://bbs.hcbbs.com/thread-5668900-1-1.html (Source: Haichuan Chemical Industry Forum)

Adding titanium to the material system can improve corrosion resistance

There are several AI-generated answers that are just filler; almost everyone tried to respond, but it’s unclear what they actually said