Material for oxygen starved environment 1

[jaypearce]

Hi, I am looking for a recommendation for a material to be used in a nitrogen atmosphere ,1% oxygen or less. The material needs to to be capable of handling 150 degrees C with some sea water vapour and trace amounts of organic solvents (benzine, toluene, xylene). We don't think that stainless will work (304/316) because of the low oxygen and the chlorides in the sea water, but we are looking at galvanized steel. Any ideas would be appreciated

Jay

 

[EdStainless]

Chloride pitting will be a limiting factor, not to mention SCC. Try looking at high alloy stainless, either a 6%Mo superaustenitic or (if you don't need to weld) a superferritic.

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Corrosion never sleeps, but it can be managed.

http://www.trenttube.com/Trent/tech_form.htm

 

[jaypearce]

EDStainless,

I am familiar with the 6% Moly stainless (254sma/al6xn) but I am less familiar with the "super ferritic" steels. what grade or common name would I find them under?

Jay

 

[EdStainless]

They are covered by ASTM A268. The only two in production are S44735 (AL29-4C) and S44660 (Sea-Cure). These will both work well in seawater. They are only available in thin sheet and you don't want to put any un-annealed welds into service.
These alloys are normally only used as tubing. The 6% Mo alloys (254, 6XN, 1925 et. al.) are often used for the componants that require thicker material or field welding.

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Corrosion never sleeps, but it can be managed.

http://www.trenttube.com/Trent/tech_form.htm

 

[mcguire]

I don't disagree with EdStainless; Trent Tube is extremely well experienced in high alloy stainless, but I ask why the alternative of 2507-type duplex wasn't one of the recommended solutions.

 

[jaypearce]

My weld shop vendor seems to like this "duplex" material as well, they say it welds very nicely. They do a good job of the 254SMO, but they complain alot.

 

[mcguire]

It has the corrosion resistance you need as well as greater strength and resistance to SCC than the straight austenitic and greater strength and toughness than the ferritic.

 

[EdStainless]

Simple oversight. Sorry. Since the superduplex alloys aren't very available in light gage product I don't work with them much.
They would be a good option here.
The more traditional option for this srevice would probably be Monel. Any of the other options listed would work as well or better, have higher strength, and be less expensive.

= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.

http://www.trenttube.com/Trent/tech_form.htm

 

[jaypearce]

thanks to all. You have been most helpful
Jay