Upgrading 304 Stainless 2

[Baheej]

Are there any finishes/treatments/processes that can be done to "upgrade" 304/304L Stainless parts (i.e. tubes, elbows, bellows ... etc.) into a corrosion resistance state close to that of the 316/316L?
The parts are being used in intake and exhaust systems on a fuel cell, so they'll be experiencing temperatures around 80C (max), also water as a by product is present.

Any suggestions are appreciated.

Thanks,

 

[TVP]

If the components have not been passivated and/or electropolished, then do this. Otherwise, there is nothing that can make 304 as good as 316. The 2% Mo in 316 is there for a reason...

 

[mcguire]

If the 304 hasn't yet been produced there is a lot of latitude within the 304 spec to enhance it. Specify very low sulfur;less than 0.002% can easily be achieved. Ask that it be titanium deoxidized. This is routinely done by producers such as Allegheny for 316, and it does a great deal. TVP is right in that an electropolished surface finish is the single best thing you can do. If that's not possible a bright annealed surface is almost as good. Much 316 contains 0.008% or more sulfur which I have data to prove results in pitting corrosion resistance no better than ultra low sulfur 304.