Selection of nitric acid pipelines.
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What material is suitable for nitric acid pipelines? Steel-lined F4 or aluminum pipe?
It depends on the concentration of nitric acid and the cost of the pipes
We’re using 304L, and so far it’s performed well~ There is some corrosion though; actually, the best option would be one with a Teflon lining
I’m using 98% nitric acid at room temperature.
With such a high concentration of nitric acid, and at room temperature, both F4-lined steel and aluminum pipes are suitable; choose the one that is cheaper!
Are aluminum pipes good? What concentration of nitric acid can be used with 304?
If what the poster is referring to is 98% nitric acid, it is likely fuming nitric acid. It is recommended that the poster use aluminum as the material for the delivery pipes, as this is a good choice: aluminum has an oxide layer on its surface that provides passivation, and it is also cost-effective; therefore, aluminum is an ideal material for containers and pipes used with concentrated nitric acid.
It is recommended to use KY704, which is steel specifically designed for concentrated nitric acid; if the temperature of the nitric acid is low, ultra-low carbon stainless steels such as 316L can also be used. 704 can withstand 98% acid at room temperature, while at high temperatures KY706 or highly pure aluminum is required.
Under normal circumstances, 0Cr18Ni9 is sufficient; if the temperature of nitric acid is high, the stainless steel needs to be heat-treated
For 98% nitric acid at room temperature, I suggest using one of the following materials for greater safety; these materials are: 0Cr13Si4NbRe