High Pressure Manifold Material (Brass vs. SS) 1

[rendoko]

Looking across the industry I find that high pressure bottle manifolds for hydrogen delivery are constructed from brass. Does anyone know of a reason why stainless steel can not be used in place of hydrogen? I've read some place that the removal of carbon from the steel creates voids into which the hydrogen diffuses and for some reason weakens it. Has anyone heard of this?

 

[ICman]

According to my Swagelok Manual, 316 SST has actually better corrosion resistance than brass when used for (cold) hydrogen gas service. You may need to check the seal material, though (TFE is good).

Brass is probably common due to its lower cost.

. . . Steve

 

[mcguire]

Austenitic stainless steel is resistant to hydrogen embrittlement, which would be the only reason to be wary. Using a stable grade, like 316, is preferred. If temperatures exceed 100C, stick to copper-based materials becasue of the risk of hydrogen problems.
You can use ferritic stainless if hardness is kept below 100 Rb.

 

[rendoko]

Thankyou to ICman and mcguire. Materials engineering at my place of business have confimed mcguire's input.