Liquid Oxygen/440C Compatibility 1

[cbert]

Does anyone know of a NASA or MIL-STD that deals with the compatibility of liquid oxygen and 440C and other stainless steels? I'm looking more for chemical resistance than ignition resistance.

 

[unclesyd]

I have no listings for the martensitic stainless steels in any of my cryogenic reference books. None of my data sheets have any information on 440C at low temperatures.
As both C/S, 9%Ni, and S/S are used with LO2 I can see no problem with corrosion.
As you are probably aware it’s the gas phase that does the damage. You are well below the ignition point of metals.

I would expect the 440C S/S to be very brittle at LO2 temperatures.

If there is any data you will probably find it in the ASM Materials Handbook.

http://www.asminternational.org

 

[israelkk]

I think the best is to go to

http://assist.daps.dla.mil/quicksearch/

and do a search with the "liquid oxygen" keywords. I did such a search and found for example MIL-D-19326H Title: DESIGN AND INSTALLATION OF LIQUID OXYGEN SYSTEMS IN AIRCRAFT, GENERAL SPECIFICATION FOR

This MIL-STD lists many other MIL-STD and MS parts for use with liquid oxygen. The MS usually give the material for the part.

 

[stanweld]

304/304L and 316/316L are most commonly used in LOX service.
440C and other ferritic and martensitic S.S. have nil ductility/toughness at the cryogenic temperature of LOX as indicated by unclesyd.

 

[BobUXL]

As stanweld, you need a material with good cryogenic properties. Another alloy to consider is 304Cu (a 304 with 3/3.5% Cu). It has all the properties of 304 with increased corrosion resistance, better ductility (for forming) and has better machininability than 304L. This alloy is typically seen in Europe and does not have much of a presence in the US. I know that the Ugine Savoie Imphy mill in Europe make this alloy and can be obtained in the US.

 

[mcguire]

The 2XX stainless steels work better at cryogenic temperatures than the 3xx series, because they have better austenite stability, and they are cheaper. Try 201. Most US cryogenic vessel manufacturers use it.