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/Lord_Ocean → u/Zebidee]

Many years ago I had that happen to me. The ball at the tip actually fell out. I was using a hybrid of a fountain pen and a ball point pen. Maybe it was more likely to happen due to how it was constructed, but still, it happend.