Hi
Hydrogen, like oxygen is supplied as a compressed gass, unless it is cryogenic. (Oxygen that is, cryogenic H is rather exotic.) This means that if the strength of the cylinder is critical, then they should probably be the same. You can check this by looking at the pressure rating stamped on the Hydrogen cylinder and comparing it to that on an Oxygen cylinder.
There will be no liquid H present in the cylinder, but could have residual hydrogen gas, so filling with water should solve that problem.
Under certain circumstances, H can lead to embrittlement of steel, so it may be possible that a particular steel is used that is more resistant to hydrogen embrittlement in the H cylinder than is used in the oxygen cylinder. If you need to weld the cylinder (I do not know what a bowling ball cannon is.) then this may cause problems if you have a Mo steel, which is what is often used in H service. (Not sure if it is used for H cylinders though, because the service temperature is low, so should not suffer H embrittlement, but you never know what the design conditions for the cylinder could be!) The material specification should be stamped somewhere on the cylinder, so you should find it if you look.
Hope this helps.
Regards
Niekie
I agree with ozniek.
I'd say for sure that both tanks have been designed and built to ASME VIII Div 1.
If so, they must have an identification plate specifying the material, design pressure, service etc.
If they've been used to store oxygen and hydrogen and now they're out of use, they still contain oxygen and hydrogen at atmospheric pressure. So, be careful! Hydrogen is a combustible gas (it produces fire) and oxygen is a comburent gas (it feeds fire).
Don't attempt to cut or weld the tanks without having taken the necessary precautions. Fill the tanks completely with water and drain them later, as ozniek suggests. Attention though! When you fill the tanks with water, oxygen and hydrogen are released. During the operation, take care that there are no flames nor running motors nearby. Don't light cigarettes and don't switch the light on or off.
Giovanni S. Crisi
Sao Paulo - Brazil
High pressure cylinders are made of alloy steels. The Chrome-Moly steel alloys are common. You need to know what you are dealing with before attempting to weld on it.
As noted by a couple of people, there can be residual gas in the vessel. Any spark can easily ignite any residual hydrogen unless it is removed completely by a proper purged. Concentrations as low as 2% hydrogen can be explosive when any type of spark ignition source are introduced.
If you are determined to proceed with this project, make sure the vessel is properly purged before cutting it with a saw or torch. Send a small sample of the vessel to a lab to determine the chemistry so you can make an intelligent decision on what filler metal will be used, as well as how much preheat, and if any post weld heat treatment is needed.
If the vessel is made of an alloy similar to AISI 4130, a stress relief is strongly urged, and a full anneal would probably be better yet.
Cannons may be fun, but know what you are getting yourself into and the inherent dangers involved.
Best regards – Al
Thanks guys this was awesome information!!!! And greatly appreciated!. Any certain lab it needs to go to? (St. Louis area?) And general cost of something like that?
I use a lab in Pennsylvania, MMA Stork in Newtown.
The cost is somewhere around $50.00.
Just send them a small sample, maybe 1 x 1 inch.
Make sure you tell them you need the following elements: Boron, Carbon, Chrome, Copper, Manganese, Molybdenum, Nickel, Silicon, Sulfur, and Phosphorus. Iron would be the balance with a few trace elements.
Best regards - Al
Fifty bucks?
Here in Sao Paulo highly qualified labs charge 50 Reais (about 30 USDollars) and you don't need to tell them which element to search. They'll make a complete analysis listing all of the elements that can be present in a steel sample, whether they're actually present in your sample or not.
If they're not, the result will be zero%.
Giovanni S. Crisi
What is the tank specification ?
If it is DOT 3A then it is Carbon - Manganese , DOT ( or ICC ) 3AA then it is Chrome - Moly.
Which one is it ?
Good to know.
Best regards - Al
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