Hydrogen Embrittlement in brass

If you use liquid hydrogen then the answer is yes.

I have some great literature on Hydrogen Imbrittlement lying around somewhere! I've never heard hyrdrogen embrittlement happening in brass but in steel I have. Usually involves impurities in the weldment area or poor fluxing. Also, you may want to look at the type of flux being used to weld or braze that coupling. Get in touch with me and I'll look for that info for you!

Come on you guys and girls! I have posted this question and many of you have looked at it, I confess, I am unsure that Hydrogen embrittlement doe's occur in brass. If you are unsure yourself (as I am) ask a metallurgist in your department or company. I need some guidance please.

Hoping

Stan

Then if you are so suere why are you asking! IF you want the info let us know if not look it up! I am a Metallurgist and have many good friends that are Metallurgist. IF you want the info let me know or look it up!

I've never seen or heard of Hydrogen Embrittlement in brass. In stainless steel that have been stored in contact with the soil certainly, but not in brass.

Dezincification however is common in brass plumbing fittings, taps and valves.

Another form of Embrittlement that does occur in brass is caused by exposure to ammonia or mercury. This causes what looks like an Embrittlement stress fracture.

I have seen what looked like an example of Hydrogen Embrittlement in copper windings of a hydrogen cooled generator but that was not proved conclusively.

Stan,

While in general, brass is not considered to be vulnerable to hydrogen embrittlement, there are circumstances in which some alloys are somewhat susceptible, especially in the presence of other stresses or corrosive factors and whether the brass is cold worked, annealed, etc.

Could you help us by furnishing more details as to the specific application the fitting was used for, and the related conditions.

Why haven't you done this already, instead of asking such a general question, knowing there is no straightforward general answer of significance.

Regards, Greg

Stan ,

You will do well to dig into the problem -if you manufacture(Cast) these Couplings and are at wits' end trying to find out why these are failing repeatedly!

Try a link :http://www.hghouston.com/index/hghouston_Index.htm. Index tabulates Admiralty Brass-Hydrogen Emrittlement Cracks

If it is one single RED HERRING forget it!

As Greg said "Could you help us by furnishing more details as to the specific application the fitting was used for, and the related conditions."

In my works often i experimented Hydrogen ebrittlement with different metals:

in the company i'm working for, every year thousands of miles of welding are done . . .

If in the store the wire or the electrodes are exposed to dump, during welding, the high energy of electric arc is breaking the water moleculas and a certain amount of hydrogen (what is not suddenly burnt back) is diffusing in the melting bath and then in the metal.

All our metallurgist friends shall tell that the hydrogen intrusion during welding is a procedure mistake . . . . , and that some welding atmospheres are volountarily formulated with hydrogen (generally no more than 2%) . . . .

For rougth people with fast production needs, experience generally show that the hydrogen in welding is good only as part of the acetylene content.

So are you speacking of single piece brass or a welded one ?
(difficult, not impossible to make it, a little procedure unaccuracy is generating failures)

if is a single piece how was it produced: machined ? casted ? if casted how was it ?

during its life were was it put ?

atmosphere ? temperature ? contacts ?

can you give pieces of information to address the helping people ?

Thank you all for your useful comments.

This brass fitting was a cap nut on a compression fitting in a cold water plumbing system. It had failed due to stress corrosion cracking. There was no obvious source of corrosive media such a ammonia and the pipe was un-lagged, but this was classic SSC. During my investigation and examination of the fracture face on the SEM there were features present that looked very like hydrogen embrittlement (small explosion pits on the surface of the grains) I had not come across hydrogen embrittlement in brass before. I searched the WWW, but still could not get any information, hence my post for further info. Hoping that a metallurgist more experienced than myself might help. I would like to insert a photomicrograph, but I do not seem able to.

I would be glad to see any further comments

Thanks

Stan

A fruitful exercise which could add insight, would be to analyze a sample of the water.

Well water often has corrosive qualities, as can water from other sources. Utilities typically add chemical buffers to neutralize the PH. Here on Long Island, lime or caustic soda are the common additives for buffering, but the exact chemical makeup of the water varies according to which wells are providing water to a given area at a given time, how long they have been drawing water, etc. While the water is gentle on almost everything here, certain brasses (as in screws in a toilet tank) corrode severely over time, but I have no idea if hydrogen embrittlement plays any role, and have no means to check for it.

Galvanic contributions may also be a factor, because unlike most corrosion, hydrogen embrittlement takes place at the cathode.

Regards, Greg

AHA! a water system. Untreated water can liberate hydrogen sulfide--which WILL attack the brass and cause the failure type you describe.

Very True but I've seen it at high temperatures. It causes severe pitting!

Hello Stan , I am Jack in the UK.

I also have a problem with brass clips cracking / falling apart after pressing....but 3 months after pressing ! These are bright Nickel plated first them we press them onto rope to make a loop.

We have done this job for 10 years , same supplier who insists "nothing has changed" and I beleive him.

It happened at Christmas , we looked into it and decided we needed to back our press off a little still giving a strong joint.

So we made another batch , took time to inspect =all's well ,sent them to customer = all's well , customer holds stock in stores 3 months , opens box and they litterally falloff the cord in bits!

We can see no cracks when they are pressed . The failed section is dark /black not brass colour.

I have asked a professional maelas firm to look at it for us.

I'll let you know the results.

Good Luck ..to us All. Jack