Nitric acid Pipe lines

[ram21881]

why the designer select material for pipe will used for nitric acid as 304L with special containt NI > 9.5 % , why he didn't select 316L which include higher containt of NI ?

 

[metengr]

What are the process conditions for nitric acid service, concentration and temperature? Review the information below.

http://www.nickelinstitute.org/~/Me...teelandNiBearingAlloysinNitricAcid_10075_.pdf

 

[ram21881]

thanks alot metengr ,
the temperature for the nitric acidd procees various between 122 °F to 290 °F .
nitric acid with 60% concentration fed to the nitric acid storage tank

 

[metengr]

Your design for the pipe should be based on the highest temperature the pipe will see in terms of 60% nitric acid concentration. Look very closely at Figure 5 for material selection.

 

[ram21881]

so 304L special & 310L special are acceptablebut why it's specified this special NI content specially NI > 9.5 % , WHY IT'S NOT 8% , low carbon and no MO content why also?

 

[metengr]

The information is in the publication.

 

[EdStainless]

Mo does not help corrosion resistance in clean nitric acid.
I would be looking for special acid grade 310S for your application.

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P.E. Metallurgy, Plymouth Tube

 

[ram21881]

thanks alot metengr & Edstainless