ASK NDE’s TECHNICAL EXPERTS

askNDE’s technical team receives enquiries on a daily basis that require input from a stainless steel specialist.
Below is one of the questions that we received this month together with the response from our technical experts.

Q. What grade of stainless would you recommend for use with acid mine water?

      How does the price and the corrosion resistance characteristics of the different alloys stack up?  316L vs 904L vs 254SMO?

      Does NDE supply Hastelloy?

A. Acid mine waters vary considerably in their composition, depending on what treatment (if any) they have received
     before being released. In order to do a useful specification I would need to have actual water analyses.

     However I think with most mine waters 2205 would be sufficient. If the pH¹s are very low and the chlorides high,
     say above 1000ppm, then 2507 may be suitable.

     The high nickel alloys such as 254SMO, Inconel625, Hastelloy C22 or C276 have very good pitting resistance in strongly acid environments
     but are hugely expensive and are therefore used only in extreme environments (generally during manufacture of specific products).
     2507 can handle hot sea-water and has about the same pitting resistance as 254SMO. At NDE we are able to source all of these grades for you.