material selection for 100% hydrogen peroxide @ 90¦F

[weldmetal]

Would 304L SS be a good choice of material selection for a tank and pipe containing 100% hydrogen peroxide @ 90°F for a service life of 20 years minimum? Do you have other recommendations that would last as long and be less expensive?

Thank you!
Weldmetal

 

[kenvlach]

Aluminum alloys of at least 99.6% Al are preferred. The tank, piping, etc. should be given a preservice passivation/pickling with about 40% nitric acid. Suitable alloys include Al 1060, 1160, 1260, 5254 & 5652. Aluminum storage tanks improve with age, presumably due to thickening of the protective aluminum oxide film.
-- (the late) C. P. Dillon, p. 82 in Materials Selection for the Chemical Process Industries, 2nd Edn.

 

[EdStainless]

And remember, butt welded construction. No threads or crevices, no o-rings.

= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[weldmetal]

So if we use Aluminum pipe instead of 304L SS would we weld the pipe with just an Argon back purge for backing so that there would be no crevices on the ID of the pipe?

How much of a corrosion allowance should we allow for aluminium?

Thanks again!

Weldmetal

 

[metengr]

You don't need to weld with the GTAW process for aluminum, you can use the SMAW process. Filler metal selection is essential, go here for more information on welding aluminium;

http://www.alcotec.com/default.html

Crevices mentioned above are associated with weld undercut and lack of penetration. Beveling the plate to butt weld will assure a full penetration weld and reduce the formation of crevices.

Purge gas is used for the GTAW process because the filler metal being deposited is bare wire so you need to protect the weld puddle. For the shielded metal arc welding (SMAW) process, the electrode contains a flux, so it is self shielding.

 

[weldtek]

No disrespect intended to any previous posts, but, from my experience I would not recommend the SMAW process for any critical welds in aluminum. Just my opinion.

 

[metengr]

weldtek;
None taken. It all depends on the welder's skill and experience with aluminum. I did not want to lock in on any one process. I have seen some weel done girth and seam welds that were open root butt welds in aluminium tanks and vessels with SMAW.

 

[TVP]

I have to admit I was thinking along the same lines as weldtek with regards to GTAW vs. SMAW. The bulk of my experience is in the automotive and general industrial areas, where SMAW is practically nonexistant. I have had the pleasure of working with some really talented welders who are artists with GTAW, so I almost always default to GTAW when thinking about high quality weldments. Just goes to show that there is more than one way to skin a cat...