Sully,

You ask really a very important question and are hinting at the "holy grail of materials" for the new Hydrogen Economy.

Effectively, you want an inexpensive high-strength carbon steel resistant to hydrogen embrittlement.

(The other materials you cite are either lower strength or too expensive)

You are not the first to require this ... Many Universities and Research institutions are doing research in this area.
For decades now, there has been a lot of work done on the existing high-strength steel materials (X52) of our nation's Natural Gas Pipelines. These pipelines are prime candidates for transmission of hydrogen and H2/CH4 mixed fuel gasses. Resistance to hydrogen embrittlement is crucial

SANDIA Labs have been doing work for many years. The following is an important overview document that you may find useful:

https://www.energy.gov/sites/prod/files/2014/03/f1...

More pipeline information can be found here:

https://d1wqtxts1xzle7.cloudfront.net/60089954/har...

https://hal.univ-lorraine.fr/hal-02970925/document

https://www.nature.com/articles/nmat3479

Tell us more about the specifics of your project an why Stainless Steel cannot be used

Regards





MJCronin
Sr. Process Engineer

Thanks for the reply. To get a little more specific, I'm adapting an existing product to meet a hydrogen application. The current product has some wetted trim parts made from high strength carbon and alloy steels that have considerably higher strength than austenitic SST. If I use a lower strength material I would need to redesign the part in question plus the mating parts. I'm not really shooting for low cost...I can handle a cost increase to some extent.

Look at the 200 series SS alloys 219 (Nitronic 40) is a good option.
It is fairly strong as annealed, but very often used cold worked to strengths in the 150ksi range.
It does not form any martensite when cold worked (it stays fully non-ferromagnetic).
Nitronic 50 (209) has similar physical properties and slightly better corrosion resistance (and higher price).
These alloys are also legendary for their galling resistance.
Cold drawn Nitronic rod is commonly used for valve stems because of this combination of properties.
I will look, someplace I have some NASA papers on hydrogen service.

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P.E. Metallurgy, consulting work welcomed

as I recall, the chemical industry that produces ammonia NH3 has found alloys that are resistant to H2, and most are ferritic that include Vanadium trace additives.

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

Thanks Ed. I didn't realize I could use Nitronic 50 in the strain hardened condition with hydrogen.

Quote (MJCronin)

... for the new Hydrogen Economy.

Or you could decide the Hydrogen Economy is a dead end and choose another path.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

Quote (davefitz)

the chemical industry that produces ammonia NH3 has found alloys that are resistant to H2, and most are ferritic that include Vanadium trace additives.

Fertilizer production involves the intermediate compound carbamic acid, which requires austenitic stainless steels with absolutely zero ferrite or ferrite potential. These steels are 'urea grade' variants of 316 and 310.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

I strongly recommned you check with the chemical industry mfrs- the processes that lead to urea are not neccesarily related to those of hydrogen production, storage or transport. Large pressure vessels that used 2.25% cr mo- V have been used in the NH3 industry , from memory. In order to avoid reinventing the wheel and repeating past metallurgical failures, see what the chem mfrs had used over the last 50 yrs. Likewise, try to get access to their failure analysis studies to learn from past mistakes.

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

Quote (IM)

Or you could decide the Hydrogen Economy is a dead end and choose another path.

I think we're 20 years from figuring that out so hydrogen would be an excellent career path considering the venture capital available today.

Careerism ... the root cause of much of what is driving us off a cliff.
(I was not referring to 'careers' on my post.)

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

For many industrial sites using hydrogen as the storage media for renewable energy makes a lot of sense.
It would allow running wind farms and solar fields at a desired steady output to the grid and use any excess power for the electrolysers.
Right now, wind power at night and solar in the mornings goes largely unused.
Storing power in batteries is fine, if you need to use it as electricity.
But why use the most expensive storage method when in many cases hydrogen would be more serviceable.
But talk of a full-blown hydrogen economy is not going to work.
It is almost as bad as the idea of putting batteries in airplanes.

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P.E. Metallurgy, consulting work welcomed

Depends on what you mean by high strength; There are chrome moly steels suitable to above 95,000 psi yield strength ( API T-95) and greater than 105.000 yield in proprietary grades. However someone should know what they are doing; when
I retired 25 years ago no mill in the western hemisphere could produce it. It requires double Q & T. Also , I am not sure of low temperature toughness; this steel can not contain Ni and needs low Mn. You have almost limited yourself to age hardening nickel alloy. A word of caution, titanium can have problems in hydrogen. Amoco made a lot of ammonia and the concern I remember was high temperature attack not ambient temperature.

hydrogen has been used for over 75 yrs as a coolant for large electrical generators ,typically over 250MWe rating. If you use the GE design guidelines issued to every engineering firm that builds the connecting pipng , valves and pressure vessels that connect to the hydrogen cooling systems, I think you will find that extraordinary metallurgical materials are not required. If you are certain of the temperature limits you listed above, you will find economical materials are permtted, but special care is needed to prevent corrosion if underground UG piping is used. Please note that the NASA hydrogen safety guidelines prohibit the use of UG routing of hydrogen piping, but it is routed underground for most large combined cycle power plants that I am aware of, with the consequent requirement to use cathodic protection of the piping and double wall piping when in the vicinity of a building or other person-accessible containment. IMHO the most likely failure mode for older combined cycle plants may be the failure of these cathodic protection systems over time.


"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

All of our high purity gas lines (Ar, N2, He, N2) came to the plant underground, and all were installed full length double wall.
We could inspect the ends from access pits at both ends.
I hated it. Above ground it the way to go.

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P.E. Metallurgy, consulting work welcomed

Air/space tech providers of the Shuttle program might be a contact, as liquid H2 was part of the fuel and mass a critical parameter, ie high strength materials had been used.

Roland Heilmann

I believe that this thread has gotten way off course...

It was my understanding that the original question was about suitable low-cost materials for high pressure gaseous hydrogen service.
(Kinda like you would need if you wanted to use existing HP Natural Gas piping for hydrogen transport)

The implied issue, IMHO, is Hydrogen Cracking ...

I do not believe that the question is about personal experiences with whatever piping you have used for any kind of gaseous or liquid hydrogen service...

If this metallurgical question can be solved, this would be a great leap forward for energy independence and a clean economy..

Thoughts ?

MJCronin
Sr. Process Engineer

OP here. MJCronin is correct. This relates to blending natural gas with hydrogen. The issue is that some legacy materials are martensitic SSTs and higher strength carbon and alloy steels. These materials are susceptible to hydrogen environment embrittlement. Note that a higher cost is okay to some extent.