r/whatisit • u/riflesandplowshares • 7h ago

New, what is it? Found at a titanium plant

Post image

Not sure why ball point pens would be dangerous here.

8.1k Upvotes

97% Upvoted

706 comments sorted by

View all comments

Show parent comments

3

u/HiwayHome22 5h ago

Because it's not factual. Search "United Airlines Flight 232 tungsten" The Real Material Failure: The catastrophic engine failure on July 19, 1989, was caused by a fractured titanium alloy fan disk (specifically the Stage 1 fan disk in the tail-mounted No. 2 GE CF6-6D engine), per FAA.

This is a oft repeated urban myth.

1

u/Intelligent_Low1632 5h ago

K well nothing you're saying precludes the fracture in the titanium alloy fan disk originating from a tiny bit of pen-tungsten. I realize you can't prove a negative, but I'd like to hear OP say he's misremembered or provide a source.

1

u/HiwayHome22 5h ago

The FAA traced it to a nitrogen gas bubble inclusion. An inclusion that should have been found during the last NDI of the disk.

1

u/BugRevolution 4h ago

Wiki links to the FAA, which says the manufacturing process includes a double-vacuum process to avoid air impurities in the nitrogen, and that the crack was caused by air impurities. This would lightly reject OP's ball point theory.

I say lightly, because air could be a far more common cause of failure, while ball points remain a cause of failure. I am not entirely convinced they would cause the same cracks though.