The newly purchased storage tank made of stainless steel 304 has rust on it
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I would like to ask the teachers: What should be done if rust appears on a newly purchased storage tank made of 304 stainless steel? What caused it?
Generally, it is likely due to contact with carbon steel or contamination by carbon steel; probably the factory’s management is inadequate, or the item came into contact with carbon steel during transportation. Nothing can be made clear without pictures.
1. Chloride ions are present in the usage environment. Chloride ions are widely present, such as in table salt, sweat, seawater, sea breeze, soil, and so on. Stainless steel corrodes rapidly in environments containing chloride ions, even faster than ordinary low-carbon steel. Therefore, there are requirements regarding the environment in which stainless steel is used, and it needs to be wiped regularly to remove dust and kept clean and dry. 2. It has not undergone solution treatment. The alloying elements did not dissolve into the matrix, resulting in a low alloy content in the matrix structure and poor corrosion resistance. 3. This titanium- and niobium-free material has an inherent tendency to intergranular corrosion.
It might be caused by iron ion contamination
It is contaminated by iron ions; if left untreated, corrosion will worsen, which is a quality issue of the product. Have the manufacturer come to the site to handle it; a surface treatment can be applied locally using acid cleaning paste to form a passivation film.
Some current facilities do not have dedicated areas or specialized equipment for manufacturing stainless steel products; they produce these products alongside carbon steel, which leads to severe iron ion contamination. If this issue is not addressed promptly, it becomes difficult to eliminate the contamination once it penetrates deep into the material. Local acid washing and calcification treatment can be used to address this problem.
Rust appearing on new stainless steel tanks is usually due to contact with carbon steel. A simple solution is to apply some acid cleaning and passivation paste, rinse it off after half an hour, and be careful not to let it come into contact with the skin or clothing to avoid corrosion
It’s due to the manufacturing process; carburization is the cause.
The manufacturer failed to carry out proper acid washing and passivation, or contamination occurred during transportation; the manufacturer is required to perform acid washing and passivation again.
The separation between carbon steel and stainless steel was not properly implemented