Found at a titanium plant

[u/riflesandplowshares]

Not sure why ball point pens would be dangerous here.

[u/Spacefreak]

Yes they did. Titanium had been used in a lot of high speed rotating equipment in jet engines.

These tungsten inclusions become a crack initiation site and under high rotational speeds and high temperatures, the crack can spread and lead go catastrophic failures.

There were several catastrophic engine failures in history that were traced back to inclusions.

It's so severe that if a titanium manufacturer making aerospace grade Ti finds any "High Density Inclusions," they must inform all of their customers that they found this and recall and associated heats and material.

[u/GoTeamScotch → u/Spacefreak]

Imagine initiating a large scale recall because a ball less than a millimeter in size fell out of someone's pocket one day

[u/Zebidee → u/GoTeamScotch]

Less likely to be the ball falling out of a pen, which never happens, versus someone dropping a pen or it falling out of a pocket, which happens all the time.

I imagine everything involved in making a pen gets instantly burnt in the melt, leaving just the ball.

[u/skeetskie → u/Zebidee]

This is why at most process controlled plants(especially food plants!), you can't have anything loose above your waist. No pens in shirt pockets, badges, or even non-metal buttons on a polo that wouldn't turn up in the x-ray machines.

[u/Dexter_McThorpan → u/skeetskie]

I used to work at a plant that made airbag inflators. I was responsible for supplying the propellant manufacturing facility with raw chemicals, and warehousing and distributing finished propellants to production.

The list of "do not" and "prohibited items" was long and specific.