Question: When a 316L stainless steel container is used to hold dilute phosphoric acid, is it still necessary to carry out pickling and passivation?
Thread Content
Today I was looking into pickling and passivation; according to the standards, the reagents used for pickling include dilute sulfuric acid, nitric acid, and hydrofluoric acid, with a mixed solution of nitric acid and hydrofluoric acid yielding better results. My question: 1. Can it be pickled with dilute phosphoric acid? 2. If the medium is dilute phosphoric acid, does the equipment still require pickling and passivation?
This post was last edited by qugd on 2020-5-22 at 11:30. It’s still better to carry out passivation treatment. Phosphoric acid is more corrosive to stainless steel than sulfuric acid, because phosphoric acid has the ability to complex iron ions.
In other words, it’s better to carry out pickling and passivation, right?
I have another question: if the medium is dilute phosphoric acid and the material is 316L, what corrosion margin should be adopted? 1 or 2?
Phosphorus is a harmful element for steel, according to the experts mentioned above.
Do you mean to use a different material?