Regarding stainless steel corrosion resistance
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I would like to ask the experts for advice. I’m facing a problem: the fermentation storage tanks for beer malt in our company are made of 304 stainless steel. The fermentation area is disinfected approximately every 10 days, using sodium hypochlorite solution that is sprayed; as a result, liquid may end up on the exterior surface of the tanks. Over time, this leads to extensive corrosion on the outer walls of the tanks. However, it’s not pitting corrosion nor scale formation, and the inner walls are intact (probably because they are in constant use). What are some effective solutions for this issue? Would it work to use an acid pickling passivation paste? Or would applying an anti-corrosion coating after sandblasting be effective? Thank you all!
The disinfectant spray is corrosive to stainless steel; it is recommended to carry out sandblasting to achieve a Sa2.5 surface finish before applying anti-corrosion treatment, using phenolic epoxy primer or ordinary epoxy anti-corrosion primer – zinc-rich paint should not be used. For the topcoat, aliphatic polyurethane topcoat can be applied.
Painting is the most convenient option, but I’m not sure whether painting is allowed in the food industry Pickling and passivation require immersing the equipment in a pickling solution; therefore, this process is carried out before mechanical processing. Once at the site, one can only clean the surface first and then apply the pickling paste, which is a rather time-consuming task~~
Apply surface treatment first and then paint it; otherwise, the disinfectant will keep corroding the pipe walls
I’ve also worked in a brewery; the outer layer of the fermentation tanks should be a thermal insulation layer – it shouldn’t be left exposed directly. Disinfection is indeed a normal practice, but when using sodium hypochlorite for spraying, certain requirements must be followed; it should not be sprayed directly onto stainless steel pipes or equipment.
I have stainless steel pickling and passivation equipment suitable for you. The acid used does not contain strong acids and is non-corrosive; it is a European-made product that can be used to treat food processing equipment as well as pharmaceutical equipment. It operates on the principle of electrochemical reactions, and the equipment is used in combination with this acid. Contact number: 13355459578
Watching, brewing beer – it involves food hygiene, so it’s hard to say; generally, one just needs to pay attention to the frequency and method of disinfection； Or, after treating the wall surface, apply a coating – an acid and alkali resistant anti-corrosion coating
What is the operating temperature of this fermentation storage tank?
After spraying water on the stainless steel surface, it is dried.
Even passivation should be useless; it’s a material issue.
The outer wall of the storage tank is rusted; it’s easy to handle – just remove the rust and then paint it