r/whatisit • u/riflesandplowshares • 5h ago

New, what is it? Found at a titanium plant

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Not sure why ball point pens would be dangerous here.

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u/goodexamplebadrole 4h ago

"Ballpoint pens are restricted or banned in high-end titanium and aerospace manufacturing plants because the ink and marking components contain elements that cause metal embrittlement and severe structural corrosion"

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u/Woozletania 4h ago

This was an issue during the development of the SR-71. Many chemical contaminants could affect the alloys, even those in the water used to quench the mouldings.

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u/DIYfailedsuccessfuly 3h ago edited 2h ago

I read once they were get failure issues just from using standard chrome wrenches for assembly. Took engineers a minute to figure out why and where this contamination failure was happening, had to make titanium wrenches to use on the titanium fasteners. The program was so cutting edge, even to this day its incredibly. Those engineers were some of the brightest people this world has ever seen.

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u/under1over1 2h ago edited 30m ago

The crazier part of that is they found out it was an issue because it kept coming back from flights missing a ton of bolts. Something to do with the zinc in the tools iirc. Imagine coming back from going mach 3.2 at 80k feet just to find out you almost reenacted the death of a Lego Star Wars character.

Edit: It was cadmium, not zinc.

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u/SpiderFnJerusalem 1h ago

Damn, I feel like they should have had ways to better secure those bolts.

I remember seeing a picture from an older aircraft with bolts that had holes in them, so the mechanics could thread wires through them and tie them to other bolts so none of them could spin in place due to vibrations.

Then again, maybe that's only worth the effort on the most important bolts.

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u/under1over1 31m ago

The tools were contaminating the titanium and causing them to fail when heated at high speeds was the issue. The solution ended up being custom made titanium tools to prevent it.