Someone give me first-hand evidence of oxygen-related damage to a titanium SECOND stage. Any evidence. Anything at all.
Asking for a friend...
Here is a technical report.
NASA TR R-180 Reactivity of Titanium with Oxygen
The other technical report, one of the authors is Chaffey (of Grissom White and Chaffey Apollo 1 catastrophe).
The report states that in 100% gaseous oxygen they needed at least 350 psi for combustion to occur statically, but once it started, everything (metal etc) was consumed. At pressures less than 350 psi ignition was caused by one or more of the following factors:
◦Particle impact - the acceleration of “dirt” particles in the gas stream impacting a bend or T in the flowstream. You get acceleration of gas and entrained particles at the outlet of an orifice or regulator...
◦Adiabatic compression - O-rings can combust as a result of rapid pressurization, much like a diesel engine works. The o-ring then causes metal tubing and component to combust
◦Mechanical impact - Materials may spontaneously combust when they reach their autoignition temperature or pressure. Tables are readilly available with the autoignition temperatures and pressures even via google.
◦Contamination by hydrocarbons – hydrocarbons + oxygen creates a shock explosive
◦Flow induced localized heating
If you go to the Wendell Hull and Associates (no affiliation to them except I sat through their 2 day O2 and H2 safety and system design seminar) website for more information. They have lots of material from the Gemini and Apollo days when NASA learned about the materials, system design and operation of oxygen systems. They (NASA) built a test facility in White Sands, NM and ignited lots of stuff in the process of developing standards including Titanium to develop the standards.
The standard "SAFETY STANDARD FOR OXYGEN AND OXYGEN SYSTEMS" NSS 1740.15 Jan 1996 - Material Selection - 303 Metallic Materials - f Restricted Alloys - "The use of certain metals in oxygen systems must be restricted (NASA JSC SE-R-0006C latest revision). These include the following:
(1) Titanium. Of the various titanium alloys tested (alpha, AB, beta) and reported all showed very high sensitivity to mechanical impact in oxygen (Key and Riehl 1964). Titanium must not be used with LOX at any pressure or with GOX at oxyfen pressures above 207 kPa (30 psi). Tests have indicated that titanium, alpha titanium and alpha 2 titanium alloys can be ignited and sustain combustion at oxygen pressures as low as 7 kPa (1 psi). Frictional heating test conducted on titanium and titanium alloys indicated that the Pv product for ignition is extremely low (see Table B-2, Appendix B). Recent tests at WSTF indicate titanium and its alloys can also be ignited in air in friction heating tests.
Titanium allows must be avoided in storage or test facility systems since titanium is impact sensitive in oxygen.
I tried to attach the Safety Standard for Ox and Ox systems file but it is just over 10 MB. If you google it you can find it.
Anyway, there you go from 1965 to 1996 to present titanium doesn't belong in oxygen systems. An abundance of testing has shown this. There are plenty of good alloys that play nice in O2 and seawater like Monel K-500, Nickel alloys, Hastelloy, etc etc.
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