AMS 5717 Material compatibility with hydrazine 1

[vonbad]

Hello, I need some assistance in regards to material. I am working with an old print that calls out for ams-5717 specification for the material. However, the material is not available in the size requirements.

Can anyone suggest an alternate materials. It will be used with hydrazine.

 

[tbuelna]

Can you provide more details of the part, such as what manufacturing processes are involved (machining, welding, etc), what raw material size/form is needed, or what strength is needed from the material.

Here is a NASA flyer that briefly discusses the long term compatibility of some metals with MMH exposure.

 

[EdStainless]

There is a NASA handbook for comparable materials.
Unfortunately I don't have a current copy.

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Plymouth Tube

 

[btrueblood]

Used in what context, i.e. what temperature/time exposure and what level of catalytic reaction (decomposition of the hydrazine) is acceptable, and what amount of dissolved iron can you tolerate in the hydrazine. Don't say none, because that would require unobtanium.

If you deal with hydrazine quite a bit, then the book you want to find is Eckhardt Scmidt's Hydrazine and Its Derivatives, you'll probably need to visit an Engineering library to find a copy.

 

[tbuelna]

The relevant NASA Technical Standard is NASA-STD-6001.

One benefit from the billions of our tax dollars spent on NASA programs over the years is the incredible wealth of technical data from NASA research made available to the public. This information can be accessed on the NTRS website. It's a wonderful resource.

 

[btrueblood]

That NASA document describes only a short-duration exposure test, and provides no data. Probably good for polymeric materials, where the object of interest must simply retain its integrity/properties under incidental, brief exposure to hydrazine vapors and/or splashes, such as might occur during fueling of a spacecraft. A piece of pretty much any metal will likely pass a brief-duration exposure such as that.

Longer-term tests have been conducted under various contracts (NASA, DOE, DoD, and a fair number of commercial ones) to investigate storage, and/or piping, and/or reaction chamber (decomposing hydrazine), exposure of materials to hydrazine and its derivatives, and the bulk of such data has been collected (and a substantial amount of that generated) by the book author mentioned previously. Any NASA document written prior to about 10 years ago is likely cited in the most updated version of the book.

But, without the OP responding, we don't know what level of exposure his part must survive...

 

[vonbad]

Thank you all for your response.

The parts are relatively small (various sizes under 2-1/2" OD and no longer that 6"). They will be machined then welded to a 11 gauge 304L sheet metal. The temperature should not exceed 200°F and exposure per cycle would be less than 2 hrs. It should not be used more than 2 to 3 times a year.

Based on the information I did find, the ultimate tensile strength of the spec material is 107 ksi at 70°F.

I think that the material was selected primarily for the corrosion resistance, then strength with temperature lagging at the end.

I will continue to go through the NASA papers that were recommended.

thank you again

 

[btrueblood]

Use any stainless alloy, then. 304L would be perfect. If you needed something a bit stronger, a PH grade like 17-4 could be used.