Surface corrosion of stainless steel 304
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It’s a post-treatment device for sewage treatment plants, made of 304 stainless steel. After operating for some time, yellow lumps appeared on its surface; after removing those lumps, a small hole appeared. I’m seeking advice from experts – what could be the cause of this?
This may be caused by local corrosion, especially pitting. Stainless steel 304 is prone to pitting in environments containing chloride ions, resulting in small holes forming on the surface of the material. The chloride content in the environment of wastewater treatment plants may be high, thereby accelerating this process. .
Wastewater contains chloride ions and other harmful substances; 304 stainless steel is not resistant to corrosion when the pH level is acidic. The yellow substance is a corrosion product of stainless steel. It is recommended to apply coating anti-corrosion measures to the stainless steel surface depending on the conditions of wastewater use.
Stainless steel is prone to corrosion in humid environments, especially where chloride ions are present, as this can lead to pitting corrosion that results in corrosion cavities.
Check whether the medium contains elements such as chlorine and sulfur
The yellow lumps are mainly corroded rust; it seems that the anti-corrosion measures were not properly implemented. After cleaning, anti-corrosion treatment must be carried out thoroughly, otherwise this equipment will soon become unusable
We have also encountered this issue here. . .