17-4 PH with Nitrous Oxide?

[DRWeig]

Group:

I'd appreciate any opinions on use of 17-4 PH stainless for nitrous oxide service (pure NO, hospital application, 50 PSIG nominal).

Pressure sensor manufacturer claims corrosion will be severe (wetted material is all 17-4 PH SS). Gas supplier says it's fine.

If it's not fine, suggestions for a more compatible material?

Many thanks and good on y'all,

Goober Dave

 

[unclesyd]

We are running 17/4 PH SS as compressor wheel for compressing NOX. The concentration of N2O varies from about 50%, normal, to 90%. The inlet gas is saturated with H2O with temperatures form 35C to 120C. There has not been any corrosion in over 15 years service. On stream time is about 80%.
This is the only area where we use 17/4 in contact with NOX. Our material of construction is normally 304ELC or Titanium.
I don't know if the company that converts NOX to N2O uses any 17/4 wetted parts in their process.

This compressor actually compresses the off gas from our process for recycling or send it to a guest company that converts the NOX to N2O Oxide for the trades, whipped cream chargers and especially medical use.

 

[DRWeig]

Say, that's great testimony, Uncle Syd!

Thanks for responding.

Good on ya,

Goober Dave

 

[unclesyd]

Just checked on the 17/4 wheel and it's still in use and has been inspected 3 times and no problems found. The service has changed slightly in the last couple of years as it only sees NOX for 50% of the time while compressing air the remainder.

I also verified that the 17/4 wheel replaced the original Ti 6AL-4V wheel that underwent severe corrosion in this service. The Ti mentioned in my first post is Ti Gr2.

 

[DRWeig]

Thank you again, Uncle Syd.

We electrical power and controls engineers don't get the education we need in materials... Corrosive behavior, in particular, is hard to quantify.

Best to you,

Goober Dave