Seek advice on the corrosion resistance of stainless steel
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We currently have a batch of components with stainless steel (likely 304) casings, and after being used for some time, their surfaces have rusted. We now want to refurbish them. May I ask: 1) Polishing 2) Painting – what type of paint is suitable? The first option seems to be more expensive, and issues might arise after some time as well ； With the second option, considering that stainless steel does not have very good adhesion properties, it might not stick firmly? Thank you all~~~ This post was last edited by xyzq1111 on 2009-2-4 17:51.]
There is no issue with poor adhesion. Just choose the appropriate paint as needed
Since it’s rusted, rust removal must be done first, using a better quality acid cleaning and passivation paste. If 304 can rust, then the operating environment must be quite harsh; whether painting can provide corrosion protection still needs further consideration.
It seems the surrounding environment is quite harsh. If stainless steel is used for corrosion protection, then can carbon steel be used instead? And if carbon steel is used, what measures should be taken for corrosion protection?
First, the rust needs to be removed; mechanical rust removal will suffice, and then applying an epoxy-based coating will do.
Using epoxy resin is not ideal; it’s best to use plastic lining
It can be pickled and then passivated. Although 304 has the ability to self-passivate in air, passing it through a professional passivation facility results in a denser and thicker passivation layer, which improves its corrosion resistance.
If it’s genuine 304, it shouldn’t rust. During use, direct contact with ferrite should be avoided as much as possible. I guess the original poster was tricked by scammers
Under normal conditions, 304 generally does not rust； If it rusts in an acidic environment, then painting is necessary; generally, epoxy paint is used. Using a stainless steel casing is surely for aesthetic reasons; if 304 material is suitable, but the environment is corrosive, it would be better to use carbon steel with painting.
For thin-walled pipes, it’s best to consider replacing them. For thick walls, just apply paint. The price of 304 steel is quite good right now; let’s do the calculations and take a look.
1. Applying passivation treatment can improve corrosion resistance. 2. If the surface of the stainless steel is too smooth, it can be roughened first before applying the coating.