side89...
Your requirements mandate expertise in spaceflight materials and hardware. IF your company currently makes spaceflight parts and components, then one [or more] spaceflight experienced M&P engineers on-staff should be the ones to determine what to use... and know the appropriate testing to validate initial design goals.
As RB1957 implied... valve and its internal components do not work in isolation relative to the vehicle and its dynamic systems.
The reason for this is that operational environments [temperatures, chemistry, flows, materials in-contact, etc] can vary wildly... and each combination of factors has to be validated.
There are available NASA reports for valve and component design related to high rate-flows of various cryogenic fluids.
NOTE. Materials problems are likely to be Your least problems... the worst problems may include non-materials factors, such as vibrations/flutter, galling/fretting/spalling, friction, thermal shock, high-rate-wear, etc... just to name a few mechanical factors.
Regards, Wil Taylor
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